A review of the Cypriniform tribe Yunnanilini Prokofiev,2010 from China, with an emphasis on five genera based on morphologies and complete mitochondrial genomes of some species

Li-Na Du, Jian Yang, Rui Min, Xiao-Yong Chen,5, Jun-Xing Yang,6,7,＊

1 Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, Guangxi 541004, China

2 Guangxi Key Laboratory of Rare and Endangered Animal Ecology, College of Life Science, Guangxi Normal University, Guilin, Guangxi 541004, China

3 Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Nanning Normal University, Nanning, Guangxi 530001, China 4 Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China

5 Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, Nay Pyi Taw 05282, Myanmar

6 State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Innovative Academy of Seed Design,Chinese Academy of Sciences, Kunming, Yunnan 650223, China

7 Yunnan Key Laboratory of Plateau Fish Breeding, Yunnan Engineering Research Center for Plateau-Lake Health and Restoration,

Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China

ABSTRACT The loach tribe Yunnanilini from China is reviewed here using morphological characters and complete mitochondrial genomes of select species. Molecular data suggest that the tribe Yunnanilini is not monophyletic and can be divided into three clades.Species of the Yunnanilus nigromaculatus group form an independent genus and are placed in Eonemachilus. In the phylogenetic tree, Y. jinxiensis clusters with Paranemachilus genilepis, and Y.pulcherrimus clusters with Micronemacheilus cruciatus, indicating that Y. jinxiensis and Y.pulcherrimus belong to Paranemachilus and Micronemacheilus, respectively. Based on morphological data, Y. bailianensis and Y.longibarbatus are placed in Heminoemacheilus,while Y. jinxiensis and Y. pulcherrimus, are placed in Paranemachilus and Micronemacheilus,respectively. Yunnanilus niulanensis and Y.qujinensis are treated as junior synonyms of Eonemachilus caohaiensis. Eonemachilus,Micronemacheilus, and Yunnanilus are show short separation between anterior and posterior nostrils.The genera can be distinguished from each other by mouth structure, lateral line and cephalic lateral-line canals, and papillae on median part of both lips. The anterior and posterior nostrils of Heminoemacheilus and Paranemachilus are closely set. Paranemachilus and Micronemacheilus are distinguished by cheeks covered with scales and lips with papillae,respectively. Our phylogenetic tree and morphological characters support Traccatichthys as a valid genus, which can be distinguished from Micronemacheilus by anterior and posterior nostrils closely set (vs. clearly separated). Four species are placed in Traccatichthys.

Keywords:Eonemachilus; Heminoemacheilus;Micronemacheilus, Paranemachilus, Yunnanilus;Taxonomy

INTRODUCTION

Loaches belonging to Nemacheilidae are an ecologically important and taxonomically challenging family of freshwater fish distributed in mainland Asia and adjacent islands, as well as in Europe and northeast Africa (e.g., Eschmeyer et al.,2020; Kottelat, 2012; Prokofiev, 2010; Zhang & Zhao, 2016).Nemacheilidae contains 756 species belonging to 47 genera,including 269 species belonging to 22 genera in China(Appendix I, Chen, 2013; Eagderi et al., 2019; Eschmeyer et al., 2020; Gransee et al., 2019; Jiang et al., 2021; Kaya et al.,2020a, 2020b; Kottelat, 2012; ; Prokofiev, 2010; Yoğurtçuoğlu et al., 2020; Zhang & Zhao, 2016). Morphological variation in nemacheilids is often inconsistent with molecular evidence(Chen et al., 2019; Sgouros et al., 2019). For example, based on molecular analyses,Homatula,Nemacheilus,Schistura,Triplophysa, andYunnanilusexhibit polyphyly (Chen et al.,2019; Liu et al., 2012; Min et al., 2012; Sgouros et al., 2019;Tang et al., 2006).

Prokofiev (2010) studied the systematics and phylogenetic relationships of the family Nemacheilidae, and recognized five tribes (Vaillantellini Nalbant & Bǎnǎrescu 1977, Lefuini Prokofiev 2010, Yunnanilini Prokofiev 2010, Triplophysini Prokofiev 2010, and Nemacheilini Regan 1911) based on 40 morphological characters. Vaillantellini contains a sole genus,VaillantellaFowler 1904; Lefuini includes two genera (LefuaHerzensterin 1888 andOreonectesGünther 1868) from East Asia and one genus (AborichthysChaudhuri 1913) from India and Myanmar; Yunnanilini contains eight genera, includingEonemachilusBerg 1938,HeminoemacheilusZhu & Cao 1987,MicronemacheilusRendahl 1944,ParanemachilusZhu 1983,PetruichthysMenon 1987,ProtonemacheilusYang &Chu 1990,TraccatichthysFreyhof & Serov 2001, andYunnanilusNichols 1925; Triplophysini includes three genera,namely,HedinichthysRendahl 1933,OrthriasJordan & Fowler 1903, andTriplophysaRendahl 1933; and Nemacheilini, the largest tribe, contains all remaining loaches (Prokofiev, 2010).Additionally, from the phylogenetic relationships among these tribes, Vaillantellini is the most primitive group, forming sister group to the remaining four tribes; Lefuini and Yunnanilini share several primitive features. Yunnanilini originated slightly later than Lefuini; and Triplophysini and Nemacheilini form a sister group, and together into Yunnanilini (Prokofiev, 2010).

In addition to those primitive features, such as posterior of bony capsule of the swim bladder open, open part of the swim bladder and preethmoid-I present. Yunnanilini possesses several diagnostic characters, including head and body laterally compressed; anterior and posterior nostrils slightly separated (distance greater than 1/5 of eye diameter) or closely set, anterior nostril not barbel-like; abdominal axillary lobe absent; capsule of swim bladder developed; and vertebrae 32-40 (Prokofiev, 2010). Among the eight genera placed in Yunnanilini, Prokofiev (2010) consideredEonemachilus,Micronemacheilus,Paranemachilus, andYunnanilusto be valid, and thatPetruichthysis synonym toYunnanilus. Subsequently, Kottelat (2012) placedY. brevis(Boulenger 1893) and an unnamedYunnanilusspecies from Myanmar inPetruichthys, and treatedHeminoemacheilus,Protonemacheilus, andTraccatichthysas valid. Hence, the validity ofHeminoemacheilus,Petruichthys, ProtonemacheilusandTraccatichthysneed further systematic research.

Berg (1938) named the genusEonemachilusbut did not discuss its relationship withYunnanilus. In subsequent studies, several ichthyologists treatedEonemachilusas a synonym ofYunnanilus(e.g., Kottelat & Chu, 1988; Yang,1991; Zhu, 1989). Kottelat (2012) treatedEonemachilusas a valid genus, in whichE. nigromaculatus(Regan 1904),E.yangzonghaiensis(Cao & Zhu 1989), andE. longidorsalis(Li,Tao & Lu 2000) were placed based on their deep body,terminal mouth, and shared color pattern. However,Eonemachiluswas not generally accepted in subsequent studies because Kottelat (2012) did not provide persuasive arguments to support the decisions (Du et al., 2015, 2018).Hence, the validity ofEonemachilusis remains unclear.

Freyhof & Serov (2001) described the genusTraccatichthys,and referred two species fromMicronemacheilusto this genus, i.e.,T. pulcher(Nichols & Pope 1927) andT. taeniatus(Pellegrin & Chevey 1936). However, Prokofiev (2004) did not concur, naming the species from Hainan Island aMicronemacheilus zispiProkofiev 2004. Although Du et al.(2012) discussed the research history ofTraccatichthysand mentioned that the validity ofTraccatichthysis doubtful, they still treatedTraccatichthysas valid and namedT. tuberculumDu, Zhang & Chan 2012 from Guangdong Province, and placedM. zispiinTraccatichthys. However, Zhang & Zhao(2016), without providing an explanation, retainedT. pulcherandT. zispiinMicronemacheilusandT. tuberculuminTraccatichthys. AlthoughTraccatichthysis an available name,the phylogenetic relationships and diagnostic characters betweenTraccatichthysandMicronemacheilusremain vague(Du et al., 2012; Prokofiev, 2004, 2010).

One species is recorded within the genusProtonemacheilus, i.e.,P. longipectoralisYang & Chu 1990(Zhang & Zhao, 2016). Furthermore, only two species are recorded with the genusParanemachilus,P. genilepisZhu 1983 andP. pingguoensisGan 2013 (Lan et al., 2013; Zhang& Zhao, 2016).

Three species are recorded within ofHeminoemacheilus,i.e.,H. hyalinusLan, Yang & Chen 1996,H. parvaZhu & Zhu 2014, andH. zhengbaoshaniZhu & Cao 1987 (Lan et al.,2013; Zhang & Zhao, 2016; Zhu & Zhu, 2014).

In contrast, the genusYunnanilusNichols 1925, which mainly occurs in southern China and parts of Vietnam, is a taxonomically complicated genus (Du et al., 2015, 2018;Kottelat & Chu, 1988; Kottelat, 2012; Lan et al., 2013).Diagnostic characters of the genusYunnanilusinclude mouth inferior, anterior and posterior nostrils slightly separated,without elongated barbel-like structure (Kottelat & Chu, 1988).To date, 35 species ofYunnanilushave been named;however, their taxonomic status remains unclear. Initially,although Kottelat & Chu (1988) stated that species with 14 branched caudal-fin rays and without a lateral line or cephalic pores belong to the subgenusEonemachilus, they also acknowledged that these characters could be of a degenerative nature and therefore treatedEonemachilusas a junior synonym toYunnanilus. Subsequently, Yang & Chen(1995) divided the species ofYunnanilusinto thenigromaculatusandpleurotaeniaspecies groups, according to the absence or presence of lateral line and cephalic lateralline canals, respectively. Kottelat (2012) further proposed thatYunnanilusis not a monophyletic group and thatY.longidorsalis,Y. nigromaculatus, andY. yangzonghaiensisshould be placed inEonemachilusbased on their terminal mouth (vs. inferior) and special color pattern. However, for the taxonomical status of other species, Kottelat (2012) did not provide persuasive evidence, but suggested thatY. altus Kottelat & Chu 1988,Y. analisYang 1990,Y. caohaiensisDing 1992,Y. nigerKottelat & Chu 1988, andY. obtusirostrisYang 1995 could be placed inHeminoemacheilus, andY.pulcherrimusYang, Chen & Lan 2004 andY. chuiYang 1991 could be placed inMicronemacheilus. Additionally,Y. brevisandY. cruciatus(Rendahl 1944) were reclassified intoPetruichthysandMicronemacheilus, respectively (Kottelat,2012, 2013).

From 2017 to 2020, the first author of this paper re-checked 2 494 nemacheilid specimens. The aim of this study was to undertake a comprehensive review of the Chinese species of five genera (i.e.,Eonemachilus,Heminoemacheilus,Micronemacheilus,Paranemachilus, andYunnanilus) based on type specimens, original descriptions, and complete mitochondrial genome sequences. We used the complete mitochondrial genomes of Nemacheilidae species to discuss taxonomic issues within the tribe Yunnanilini.

MATERIALS AND METHODS

All care and use of experimental animals complied with the relevant laws of the Chinese Laboratory of Animal Welfare and Ethics. We examined 2 494 specimens ofEonemachilus(680),Heminoemacheilus(91),Micronemacheilus(19),Oreonectes(64),Paranemachilus(15),Protonemacheilus(1),Traccatichthys(569),Troglonectes(35), andYunnanilus(1 020) belonging to collections from the Kunming Natural History Museum of Zoology, Kunming Institute of Zoology(KIZ), Chinese Academy of Science (CAS), Guangxi Normal University, China (GXNU), Qujing Municipal Bureau of Agriculture and Rural Affairs, Fishery Administration Center,China (FACQR), Heilongtan Reservoir Administration, Shilin,China (HRAS), and Nanning Normal University, China(NNNU). Specimens ofE. bajiangensisLi 2004 (nine specimens),E.longidorsalis(eight specimens),Y.beipanjiangensisLi, Mao & Sun 1994 (11 specimens),Y.macrolepisLi, Tao & Mao 2000 (five specimens), andY.nanpanjiangensisLi, Tao & Lu 1994 (six specimens), andY.spanisbripesLi, Mao & Yan 2009 (nine specimens) were provided by W.X. Li (Appendix II). Data forY. elakatisCao &Zhu 1989,Y. forkicaudalisLi 1999,Y. ganheensisLi, Lu & Lu 2009, andY. macrositanusLi 1999 were obtained from the original descriptions. The fin tissues ofY. jiuchiensisandE.nigromaculatuswere provided by the Kunming Natural History Museum, Kunming Institute of Zoology, Chinese Academy of Science, China. Five specimens ofP. genilepiswere collected by F.G. Luo and were euthanized rapidly by an overdose of anesthetic. The right-side pectoral fin was cut and preserved in ethanol for molecular analyses.

Measurements were taken point-to-point with digital calipers to the nearest 0.1 mm. Counts and measurements were made on the left side of the specimens. Methods of counts and measurements followed Kottelat (1990). Eye diameter was measured horizontally. Abbreviations used include: A: Number of anal-fin rays; BD: Body depth at dorsal-fin origin; C:Number of branched caudal-fin rays; CPD: Caudal-peduncle depth; CPL: Caudal-peduncle length; D: Number of dorsal-fin rays; ED: Eye diameter; HL: Lateral head length; P: Number of pectoral-fin rays; PDL: Predorsal length; PPL: Pre-pelvic length; PAL: Pre-anal length; SL: Standard length; TL: Total length; V: Number of pelvic-fin rays. Visual inspection of lips,nostrils, lateral lines, cephalic lateral-line canals, and scales was performed under a binocular microscope (Leica S6D, 6.3-40x). Species identifications were based on Zhu (1989),Kottelat & Chu (1988), Kottelat (1990), Freyhof & Serov(2001), and original descriptions.

Eonemachilusnigromaculatus,P. genilepisandY.jiuchiensiswere sequenced in this research. Total genomic DNA was extracted from fin clips using traditional phenol chloroform extraction (Taggart et al., 1992). Complete mitochondrial genomes were then sequenced by the Tsingke Biological Technology Company, Beijing, China following Illumina’s protocols, including sample quality testing, library construction, library quality testing, and library sequencing.The genomic sequence data were submitted to GenBank and assigned accession Nos. MW532080-MW532082. To test the phylogenetic position ofYunnanilus, complete mitochondrial genomes of 19 nemacheilid species and two botiid species,Parabotia fasciataDabry de Thiersant 1872 andLeptobotiaelongata(Bleeker 1870) as outgroup, were obtained from GenBank. Bayesian inference was performed using MRBAYES v3.2.6 (Ronquist et al., 2012). Two runs were performed simultaneously with four Markov chains starting from a random tree. The chains were run for three million generations and sampled every 100 generations. The first 25% of sampled trees were discarded as burn-in and the remaining trees were used to create a consensus tree and estimate Bayesian posterior probabilities (BPPs).

RESULTS

Genome organization

The complete mitochondrial genomes ofE. nigromaculatus(GenBank accession No. MW532081),P. genilepis(GenBank accession No. MW532082), andY. jiuchiensis(GenBank accession NO. MW532080) were 16 594 bp, 16 562 bp, and 16 571 bp long, respectively. They contained two ribosomal RNA (rRNA) genes (12S and 16S), 22 transfer RNA (tRNA)genes, and 15 messenger RNA (mRNA) genes (16 inP.genilepis). Like in many teleost fish, most were encoded on the heavy strand (H-stand), except for NADH dehydrogenase subunit 6 (ND6) and seven tRNA genes for Gln, Ala, Asn, Cys,Tyr, Ser, Glu and Pro, which were encoded on the light strand(L-strand). The GC gene content varied from 43.59% to 43.79%.

Phylogenetic relationships

The tribe Yunnanilini, which encompassesEonemachilus,Petruichthys,Micronemacheilus,Paranemachilus,Yunnanilus,andTraccatichthys, was not monophyletic as its members were grouped into different clades with other tribes (Figure 1).Specifically,Petruichthyswas closely related toSchistura, a genus of the tribe Nemacheilini;Micronemacheilus,Paranemachilus, andY.jiuchiensisformed a clade with three genera of the tribe Lefuini; andEonemachiluswas the sister to the clade consisting of the tribes Lefuini, Nemacheilini,Triplophysini, and other members of Yunnanilini.

In addition, monophyly of the genusYunnaniluswas not supported.Yunnanilus brevis,Y. pulcherrimus, andY.jinxiensis(presented asPetruichthysbrevis,Micronemacheiluspulcherrimus, andParanemachilus jinxiensisin Figure 1, respectively) did not cluster together with the trueYunnanilus, i.e.,Y. jiuchiensis, but were closely related toSchistura,M. cruciatus, andP. genilepis,respectively. Additionally,Y.nigromaculatus(E.nigromaculatusin Figure 1) represented the most basal clade of the four tribes (Figure 1).Yunnanilus sichuanensiswas grouped withClaea dabryiwith short branches.

Figure 1 Bayesian phylogram of Yunnanilini based on mitochondrial genomes of 22 nemacheilid and two botiid species (outgroups)

Systematics

In Nemacheilidae, 10 genera, includingEonemachilus,Heminoemacheilus,Lefua,Micronemacheilus,Oreonectes,Paranemachilus,Protonemacheilus,Traccatichthys,Troglonectes, andYunnanilus, have an anterior nostril pierced at the end of a short tube. The lips ofMicronemacheilusandTraccatichthyspossess papillae (vs. lips smooth with furrows in other genera, Figure 2A-D). InLefua,Oreonectes, andTroglonectes, the anterior nostril extremity is barbel-like (vs.no barbel-like elongation in other genera). Furthermore, the anterior and posterior nostrils ofHeminoemacheilus,Micronemacheilus,Paranemachilus,Protonemacheilus, andTraccatichthysare closely set (vs. separated in other genera,Figure 2G (separated) and Figure 2H (closely set)).

Key to genera of Nemacheilidae with tube-like anterior nostrils

Figure 2 The types of lower lip, cephalic lateral-line pores and nostrils in Yunnanilini

Based on the 35 species currently assigned toYunnanilus,morphological monophyly ofYunnaniluswas not supported.Firstly, the lips can be of two types, with large papillae or with furrows. The lips ofY. pulcherrimushave large papillae and the anterior and posterior nostrils slightly separated, distance nearly 1/4 of eye diameter, hence this species is transferred toMicronemacheilusand the valid species name isM.pulcherrimus(Yang, Chen & Lan 2004). Secondly, the anterior and posterior nostrils position occurs as two types, i.e., slightly separated or closely set. The nostrils ofY. bailianensis,Y.longibarbatus, andY. jinxiensisare closely set, but are clearly separated in other species ofYunnanilus. Furthermore,Y.jinxiensishas scaled cheeks. The typical character ofYunnanilus, i.e., well-separated anterior and posterior nostrils suggests thatY. bailianensis,Y. longibarbatus, andY.jinxiensisshould not be placed within this genus. Here,Y.bailianensisandY.longibarbatusare placed inHeminoemacheilus, andY.jinxiensisis placed inParanemachilusbased on their closely set anterior and posterior nostrils and tube-like anterior nostril, with cheek scales inY. jinxiensis. Thus, the valid species names areH.bailianensis(Yang 2013),H. longibarbatus(Gan, Chen &Yang 2007), andP. jinxiensis(Zhu, Du & Chen 2009),respectivly. Thirdly, lateral line and cephalic lateral-line canals are absent in theY. nigromaculatusspecies group, but present in theY. pleurotaeniaspecies group.

In the phylogenetic tree (Figure 1),Y. nigromaculatus(E.nigromaculatusin Figure 1) did not cluster withYunnanilusbut was basal and formed as sister group with all other genera.Additionally,Y. brevis,Y. pulcherrimus, andY. jinxiensis(P.brevis,M. pulcherrimus, andP. jinxiensis, respectively, in Figure 1) are closely related toSchistura,M.cruciatus, andP.genilepis, respectively. Hence, the species currently assigned toYunnaniluscan be divided into five genera, i.e.,Eonemachilus,Heminoemacheilus,Micronemacheilus,Paranemachilus, andYunnanilus, based on morphological characters and molecular analyses (Figures 1, 2). Species of thenigromaculatusspecies group, except forY. bailianensis(moved toHeminoemacheilus),Y. longibarbatus(moved toHeminoemacheilus), andY.jinxiensis(moved toParanemachilus) are placed inEonemachilusbased on anterior and posterior nostrils slightly separated (distance larger than 1/2 of eye diameter) and lateral line and cephalic lateral-line canals absent.Yunnanilus pulcherrimusis placed inMicronemacheilusdue to large papillae on lips and anterior and posterior nostrils slightly separated (distance nearly 1/4 of eye diameter), and species of thepleurotaeniaspecies group are retained inYunnanilus.

The common character amongEonemachilus,Micronemacheilus, andYunnanilusis the well separated anterior and posterior nostrils. This group can be distinguished from each other by lateral line and cephalic lateral-line canals absent inEonemachilus(vs. present inMicronemacheilusandYunnanilus) and papillae on lips present inMicronemacheilus(vs. absent inEonemachilusandYunnanilus).

HeminoemacheilusandParanemachilusshare closely set nostrils but can be separated from each other by cheek scales present inParanemachilusvs. absent inHeminoemacheilus(Figure 2).

Eonemachilus Berg, 1938

EonemachilusBerg, 1938: 314 (type species:Nemacheilus nigromaculatusRegan, 1904: 192). Kottelat, 2012: 82.

Diagnosis:Head and body deep, laterally compressed.Anterior and posterior nostrils well-separated (distance larger than 1/2 of eye diameter), posterior nostril closer to eye than to anterior nostril. Lateral line and cephalic lateral-line canals absent.

Remarks:Although some ichthyologists treatedEonemachilusas a synonym toYunnanilus(e.g., Kottelat & Chu, 1988;Yang, 1991; Zhu, 1989), Kottelat (2012) treatedEonemachilusas a valid genus, withE.nigromaculatus,E.yangzonghaiensis, andE. longidorsalisplaced in this genus based on deep body, terminal mouth, and special color pattern. In this study, species of thenigromaculatusspecies group are placed inEonemachilusbased on anterior and posterior nostrils well-separated (distance larger than 1/2 of eye diameter), lateral line and cephalic lateral-line canals absent, and mouth terminal or inferior. This result was supported by molecular data forE. nigromaculatus(Figure 1).

Key to species of Eonemachilus

Eonemachilus altus (Kottelat & Chu, 1988)

Yunnanilus altus, Kottelat & Chu, 1988a: 72, fig. 6 (type locality: Xiaoshuiho at Haijiashao, Zhanyi County, Yunnan,China); Chu & Chen, 1990: 17-19, fig. 12.(Figure 3E1; Supplementary Figure S1A)

Material examined:Twelve specimens. Paratypes KIZ1977001324, 1329, 1340-341, 1343, 1346-1347, 1349,1374, 1376, 1378, 1396, 43.5-56.1 mm SL; Xiaoshuiho at Haijiashao, Zhanyi County, Yunnan, China, N25.6603°,E103.9647°, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; pectoral fin with 11-12 branched rays; caudal fin with 14 branched rays; 2 outer and 12 inner gill rakers on first gill arch; processus dentiformis present; eye diameter 16%-22% HL; body depth 25%-31% SL; caudal-peduncle length 90%-116% of its depth.

Description:Body deep, compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 4 simple and 9 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 11-12 branched rays; pelvic fin with 8 branched rays; caudal fin with 14 branched rays. 2 outer and 12 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils well-separated(distance larger than 1/2 of eye diameter), posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like.Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin base, predorsal length 53%-57% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank dark brown, belly and lower part of flank brownish, covered with minute, dark brown, irregular blotches above level of pectoral fins. Fins hyaline.

Distribution:Known only from the Nanpanjiang River, a Pearl River tributary.

Remarks: Eonemachilus altuscan be distinguished from other congeneric species by body covered with scales, outer gill raker on first gill arch present, caudal fin with 14 branched rays, and eye diameter 16%-22% of lateral head length.

Eonemachilus bajiangensis (Li, 2004)

Yunnanilus bajiangensisLi, 2004: 94 (type locality: Heilongtan Reservoir, Shilin County, Yunnan, China).(Figure 3E2; Supplementary Figure S1B)

Material examined:Nine specimens. Paratype HRAS9504004 and 8 uncat., 34.8-56.6 mm SL; Heilongtan Reservoir, Shilin County, Yunnan, China, N24.7635°,E103.3057°, Bajiang drainage, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; 1-2 outer and 11-12 inner gill rakers on first gill arch; pectoral fin with 9 branched rays; caudal-peduncle length 9%-13% SL; head width 51%-66% HL; caudal-peduncle length 78%-99% of its depth.

Description:Body deep, compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 3 simple and 9 branched rays; anal fin with 3 simple and 5-6 branched rays;pectoral fin with 9 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 14 branched rays. 1-2 outer and 11-12 inner gill rakers on first gill arch. Mouth terminal; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils well-separated,posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin base, predorsal length 52%-56% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle length less than its depth. Caudal fin straight.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank yellow-brown, belly and lower part of flank yellowish. Back of body with 15-18 large, dark brown spots, lateral body with irregular short bars above level of pectoral fins. Fins hyaline.

Distribution:Known from only Bajiang drainage, Nanpanjiang River, a Pearl River tributary.

Figure 3 Map showing distribution of species of Eonemachilus,Heminoemacheilus, Paranemachilus, Micronemacheilus, and Yunnanilus

Remarks:In the genusEonemachilus,E. bajiangensis,E.altus,E. nigerandE. nigromaculatusshare 1-2 outer gill rakers on first gill arch. However,E. bajiangensiscan be separated from these species by possessing pectoral fin with 9 branched rays (vs. 11-12).

Eonemachilus caohaiensis (Ding, 1992)

Yunnanilus caohaiensisDing, 1992: 489-491 (type locality:Lake Caohai, Weining County, Guizhou, China).

Yunnanilus niulanensisChen, Yang & Yang, 2012: 58 (type locality: Yanglinhe River, Songming County, Yunnan, China)(new synonym).

Yunnanilus qujinensisDu, Lu & Chen, 2015: 249-254 (type locality: spring near Hujiafen Reservoir, Qujin City, Yunnan,China) (new synonym).

(Figure 3E3; Supplementary Figure S1C-E)

Material examined:Thirty-seven specimens, KIZ1990004187-4188, 4190, 1996003121-3122, 3124-3125, 3127, 46.7-67.8 mm SL; Lake Caohai, Weining County, Guizhou, China,N26.8506°, E104.2344°, a Yangtze River tributary.KIZ20060281, 287, 291-293, 45.5-55.2 mm SL; Yanglinhe River, Songming County, Yunnan, China, N25.2428°,E103.0648°. KIZ2013000636-659, 54.0-58.6 mm SL; spring near Hujiafen Reservoir, Qujin City, Yunnan, China,N25.4189°, E103.9511°.

Diagnosis:Whole body covered with scales; pectoral fin with 10-11 branched rays; caudal fin with 14 branched rays; outer gill rakers on first gill arch absent, 9-13 inner gill rakers on first gill arch; processus dentiformis present; body depth 22.1%-29.9% SL.

Description:Body deep and compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 4 simple and 9-10 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 10-11 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 14 branched rays. Outer gill rakers on first gill arch absent, 9-13 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis present on upper jaw,shallow median notch on lower jaw. Anterior and posterior nostrils well-separated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized,eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin base, predorsal length 52%-60% SL. Anal fin straight, tip reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle length 66%-105% of its depth. Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper 2/3 of flank dark brown, covered with large brown spots, belly and lower part of flank brownish. Fins hyaline or rays brown.

Distribution:Known from Jinsha and Nanpanjiang rivers.

Remarks:AlthoughY. caohaiensis,Y. niulanensisandY.qujinensiswere described as separate species in earlier researches (Chen et al., 2012; Ding, 1992; Du et al., 2015), it is difficult to identify these species based on morphological characters alone. Chen et al. (2012) stated thatY. niulanensiscan be distinguished fromY. caohaiensisby caudal-peduncle length less than its depth (vs. larger than or equal to its depth),and fins hyaline (vs. fins brown or black-brown). However, the CPL 73%-91% of its depth inY. niulanensis(vs. 84%-105%inY. caohaiensis) and fins obviously not hyaline inY.niulanensis(Supplementary Figure S1E). Additionally, Du et al. (2015) stated thatY. qujinensiscan be distinguished fromY. caohaiensisandY. niulanensisby dorsal fin with 10 branched rays (vs. 11). However, a difference of only one in the number of dorsal fin branched rays is not a reliable species diagnosis, as most branched rays among species could be within that range. Hence,Y. niulanensisandY.qujinensisare treated as synonyms toY. caohaiensis, under the valid species nameE. caohaiensis.Eonemachilus caohaiensiscan be distinguished from other congeneric species by mouth inferior, body scaled, outer gill rakers on first gill arch absent, caudal fin with 14 branched rays and eye diameter 16%-26% HL. Kottelat (2012) considered thatY.caohaiensiscould be a species ofHeminoemacheilus.However,Y. caohaiensisis placed inEonemachilusdue to anterior and posterior nostrils well-separated and lateral line and cephalic lateral-line pores absent.

Eonemachilus longidorsalis (Li, Tao & Lu, 2000)

Yunnanilus longidorsalisLi, Tao & Lu, in Li, Tao, Mao & Lu,2000: 350, figs. 4-6 (type locality: Agang Longtan pool,Luoping County, Yunnan, China).

Eonemachilus longidorsalis, Kottelat, 2012: 82.

(Figure 3E4; Supplementary Figure S1F)

Material examined:Eight specimens. HRAS9506001-3, 5 uncat., 25.0-40.0 mm SL; Agang Longtan pool, Luoping County, Yunnan, China, N25.0765°, E104.1091°, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; dorsal fin with 11-12 branched rays; anal fin with 7 branched rays; pectoral fin with 10 branched rays; caudal fin with 14 branched rays;outer gill rakers absent, 12 inner gill rakers on first gill arch;caudal-peduncle length 141%-190% of its depth.

Description:Body deep, compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 4 simple and 11-12 branched rays; anal fin with 3 simple and 7 branched rays; pectoral fin with 9-10 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 14 branched rays. Outer gill rakers absent, 12 inner gill rakers on first gill arch. Mouth terminal; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils wellseparated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin close to middle of snout tip and caudal-fin base, predorsal length 47%-52% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin straight.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestine straight.

Color pattern in formalin:Body and head brownish, covered with minute, dark brown, irregular blotches above level of pectoral fins, except lateral body, from body capsules to vertical half of pectoral fin. Dorsal fin, anal fin, and caudal fin with two lines of brown spots, other fins hyaline.

Distribution:Known from Nanpanjiang River, a Pearl River tributary.

Remarks:In the genusEonemachilus,E. longidorsalisandE.

yangzonghaiensisshare outer gill rakers on first gill arch absent and mouth terminal. However,E. longidorsaliscan be separated fromE. yangzonghaiensisby whole body covered with scales (vs. only caudal peduncle scaled).

Eonemachilus niger (Kottelat & Chu, 1988)

Yunnanilus niger, Kottelat & Chu, 1988: 73, fig. 8 (type locality: Tatantze, Luoping County, Yunnan, China); Chu &Chen, 1990: 16, fig. 10.

(Figure 3E5; Supplementary Figure S1G)

Material examined:Holotype KIZ1980001275, 60.5 mm SL;Tatantze, Luoping County, Yunnan, China, N24.6563°,E104.3663°, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; pectoral fin with 12 branched rays; caudal fin with 14 branched rays; two outer and 11 inner gill rakers on first gill arch; processus dentiformis present; eye diameter 15% HL.

Description:Body deep, compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 11 branched rays; pelvic fin with 8 branched rays; caudal fin with 14 branched rays. Two outer and 11 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth,lower lip thick, with strong furrows. Processus dentiformis present on upper jaw, shallow median notch on lower jaw.Anterior and posterior nostrils well-separated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like.Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin base, predorsal length 55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth larger than its length. Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins and on dorsal midline in front of and behind dorsal fin. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and fins black, without clear color pattern.

Distribution:Known from the Nanpanjiang River, a Pearl River tributary.

Remarks:Kottelat (2012) considered that this may be a species ofHeminoemacheilus, but it is placed inEonemachilusbased on anterior and posterior nostrils wellseparated and lateral line and cephalic lateral-line canals absent.Eonemachilus nigercan be distinguished from other congeneric species by mouth terminal, two outer gill rakers on first gill arch, and eye diameter 15% HL.

Eonemachilus nigromaculatus (Regan, 1904)

Nemachilus nigromaculatus Regan, 1904: 192 (type locality:Yunnan fu = Lake Dianchi in Kunming, Yunnan, China).

Yunnanilus nigromaculatus, Kottelat & Chu, 1988: 68, fig. 2;Chu & Chen, 1990:14, fig. 8.

Eonemachilus nigromaculatus, Kottelat, 2012: 82, fig. 10.8.2.(Figure 3E6; Supplementary Figure S1H)

Material examined:Two specimens. KIZ0000001695-1696,56.8-72.5 mm SL; Yunnan fu = Lake Dianchi in Kunming,Yunnan, China, N24.9525°, E102.6515°. KIZ2015003550 was sequenced in Luquan County, Kunming, Yunnan, China,N25.5615°, E102.4735°, collected by S. W. Liu, October 2015.

Diagnosis:Whole body covered with scales; pectoral fin with 11-12 branched rays; 3-5 outer and 11-12 inner gill rakers on first gill arch; processus dentiformis present; head width 20%-22% SL; caudal-peduncle length 78%-80% of its depth.

Description:Body deep, compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 4 simple and 8-9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 11-12 branched rays; pelvic fin with 7 branched rays; caudal fin with 14 branched rays. 3-5 outer and 11-12 inner gill rakers on first gill arch. Mouth terminal;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils wellseparated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 56%-58% SL. Anal fin straight, tip reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth larger than its length. Caudal fin straight.

Body covered with embedded scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head brownish, covered with minute, dark brown, irregular blotches above level of pectoral fins, belly and lower part of flank yellowish. Fins hyaline.

Distribution:Known from Dianchi basin.

Remarks:In the genusEonemachilus,E. nigromaculatus,E.altus,E. bajiangensisandE. nigershare gill rakers on first gill arch present. However,E. nigromaculatuscan be separated from these species by mouth terminal (vs. inferior), 3-5 outer gill rakers on first gill arch (vs. 1-2), and head width 20%-22%SL (vs. less than 20% SL).

Eonemachilus obtusirostris (Yang, 1995)

Yunnanilus obtusirostris, Yang, in Yang & Chen, 1995: 21, fig.6 (type locality: West Dragon Spring, Chengjiang County,Yunnan, China).

(Figure 3E7; Supplementary Figure S1I)

Material examined:Three specimens. Paratypes KIZ1987005735, 1987004002-4003, 24.5-37.8 mm SL; West Dragon Spring, Chengjiang County, Yunnan, China,N24.6930°, E102.8856°, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; pectoral fin with 9-10 branched rays; caudal fin with 15-16 branched rays;outer gill rakers absent, 10 inner gill rakers on first gill arch;processus dentiformis absent.

Description:Body compressed laterally. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 9-10 branched rays; pelvic fin with 6 branched rays; caudal fin with 15-16 branched rays.Outer gill rakers absent, 10 inner gill rakers on first gill arch.Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis absent on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils well-separated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin base, predorsal length 53%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth larger than its length. Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank dark brown, belly and lower part of flank brownish, without clear color pattern. Fins hyaline.

Distribution:Known from Nanpanjiang River, a Pearl River tributary.

Remarks:Eonemachilus obtusirostriscan be distinguished from other congeneric species by caudal fin with 15 or 16 branched rays and processus dentiformis absent.Furthermore,E. obtusirostriscan be distinguished fromE.altus,E. bajiangensis,E. nigromaculatus, andE.nigerby outer gill raker on first gill arch absent (vs. present), fromE.yangzonghaiensisandE. longidorsalisby inferior mouth (vs.terminal), and fromE. pachycephalusby pectoral fin with 9-10 branched rays (vs. 12).

Eonemachilus pachycephalus (Kottelat et Chu, 1988)

Yunnanilus pachycephalus, Kottelat & Chu, 1988: 74, fig. 10(type locality: Weizhangho at Yangliu, Xuanwei County,Yunnan, China); Chu & Chen, 1990: 16-17, fig. 11.

(Figure 3E8; Supplementary Figure S1J)

Material examined:Nine specimens. Paratypes KIZ1982002829, 2831, 2834, 2849, 2863, 2872, 2890, 2893,2897, 42.2-59.5 mm SL; Weizhangho at Yangliu, Xuanwei County, Yunnan, China, N26.6191°, E104.2753°, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; pectoral fin with 12 branched rays; caudal fin with 14 branched rays; outer gill rakers absent, 11 inner gill rakers on first gill arch; processus dentiformis present; maximum head width 13%-15% SL.

Description:Body compressed laterally. Dorsal fin with 4 simple and 9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 12 branched rays; pelvic fin with 8 branched rays; caudal fin with 14 branched rays. Outer gill rakers absent, 11 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils wellseparated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin base, predorsal length 54%-56% SL. Anal fin straight, tip reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin reaching anus. Caudalpeduncle length 93%-133% of its depth. Caudal fin emarginate.

Body covered with embedded scales, except belly in front of pelvic fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestine straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish, back with dark brown pigment forming irregular larger spots. Fins hyaline.

Distribution:Known from the Nanpanjiang River, a Pearl River tributary.

Remarks:In the genusEonemachilus,E. pachycephalus,E.caohaiensis,E. longidorsalis, andE. obtusirostrisshare whole body covered with scales and outer gill rakers on first gill arch absent. However,E. pachycephaluscan be separated from congeneric species by the following combination of characters: processus dentiformis on upper jaw present (vs.absent inE. obtusirostris), inferior mouth (vs. terminal inE.longidorsalis), pectoral fin with 12 branched rays (vs. 9-11 inE. caohaiensis,E. longidorsalisandE. obtusirostris), lateral head length 27%-29% SL (vs. 25%-26% inE. obtusirostris,30%-32% inE. caohaiensis), head height 47%-55% HL (vs.greater than 57% inE. obtusirostrisandE. longidorsalis).

Eonemachilus yangzonghaiensis (Cao & Zhu, 1989)

Yunnanilussp., Kottelat & Chu, 1988: 85, fig. 20.

Yunnanilus nigromaculatus yangzonghaiensisCao & Zhu, in Zheng, 1989: 45, fig. 23 (type locality: Lake Yangzonghai,Yiliang County, Yunnan, China).

Yunnanilus yangzonghaiensis, Zhu, 1989: 19-20, fig. 10.

Without specimens, from description by Zhu (1989).(Figure 3E9)

Diagnosis:Only caudal peduncle scaled; pectoral fin with 9-10 branched rays; caudal fin with 12-14 branched rays(mostly 14); outer gill rakers absent, 11-14 inner gill rakers on first gill arch; mouth terminal, processus dentiformis present;caudal-peduncle length 120%-160% of its depth.

Description:Body deep, compressed laterally, dorsal and ventral profiles strongly convex. Dorsal fin with 3 simple and 9-11 branched rays (mostly 10); anal fin with 3 simple and 5 branched rays; pectoral fin with 9-10 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 12-14 branched rays(mostly 14). Outer gill rakers absent, 11-14 inner gill rakers on first gill arch. Mouth terminal; upper lip smooth, lower lip thick,with strong furrows. Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils well-separated, posterior nostril closer to eye than to anterior nostril, anterior nostril tube-like. Eyes medium sized,eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Predorsal length 50%-54% SL. Anal fin straight, tip not reaching base of caudal fin base. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus.Caudal-peduncle depth less than its length. Caudal fin emarginate.

Body scaleless, except caudal peduncle. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head brownish, covered with minute, dark brown, irregular blotches above level of pectoral fins. Dorsal and caudal fins with brown spots, other fins hyaline.

Distribution:Known from Lake Yangzonhai, N24.9412°,E103.0119°, Nanpanjiang River, a Pearl River tributary.

Remarks:Eonemachilus yangzonghaiensiscan be separated from other congeneric species by body scaleless, except caudal peduncle (vs. whole body scaled).

Heminoemacheilus Zhu & Cao, 1987

HeminoemacheilusZhu & Cao, 1987: 324 (type species:Heminoemacheilus zhengbaoshaniZhu & Cao, 1987: 324).

Diagnosis:Lateral line incomplete, not reaching end of pectoral fin when folded backward or absent. Anterior and posterior nostrils closely set, anterior one tube-like. Mouth inferior. Check scaleless. Papillae on lips absent.

Remarks:Heminoemacheilus parvais placed inTroglonectes

based on the anterior and posterior nostrils slightly separated,anterior nostril barbel-like. Additionally, two species of

Yunnanilus, i.e.,Y. bailianensisandY. longibarbatus, are here referred toHeminoemacheilusdue to anterior and posterior nostrils closely set, cheeks scaleless, and lips smooth, without papillae.

Key to species ofHeminoemacheilus

Heminoemacheilus bailianensis (Yang, 2013)

Yunnanilus bailianensis, Yang, in Lan et al., 2013: 51-55, figs.36, 37 (type locality: Bailian Cave, Liuzhou City, Guangxi,China).

(Figure 3H1; Supplementary Figure S2A, E)

Material examined:Four specimens, GXNU201801-4,26.3-33.4 mm SL; Bailian Cave, Liuzhou City, Guangxi,China, N24.2116°, E109.4338°, Hongshui River, a Pearl River tributary.

Diagnosis:Processus dentiformis absent; lateral line and cephalic lateral-line pore absent. One outer gill raker and 12-13 inner gill rakers on first gill arch. Lateral head length 29%-30% SL; head depth 49%-51% HL. Caudal fin forked.

Description:Body compressed laterally. Dorsal fin with 3 simple and 8-9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 12-13 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays.Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis absent on upper jaw. Anterior and posterior nostrils closely set, anterior nostril tube-like.Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 53%-58% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin reaching anus. Caudalpeduncle depth less than its length. Caudal fin forked. Body almost scaleless.

Color pattern in formalin:Back and upper part of flank yellow, belly and lower part of flank yellowish. Vertical black stripe along lateral line wider than pupil from posterior operculum to base of caudal fin. Fins hyaline.

Distribution:Known from Bailian Cave, Hongshui River, a Pearl River tributary.

Remarks:Lan et al. (2013) describedY. bailianensisas scaleless, but a few scales were observed in specimens from the type locality.Yunnanilus bailianensispossesses typicalHeminoemacheiluscharacters, i.e., anterior and posterior nostrils closely set, anterior one tube-like, cheeks scaleless,and lips without papillae. Hence,Y. bailianensisis placed inHeminoemacheilusin this study. The species can be distinguished from other congeneric species by lateral line and cephalic lateral-line absent and caudal fin forked.

Heminoemacheilus hyalinus Lan, Yang & Chen, 1996

Heminoemacheilus hyalinusLan, Yang & Chen, 1996: 109(type locality: subterranean water outlet near Bao’an Town,Du’an County, Guangxi, China).

(Figure 3H4; Supplementary Figure S2C)

Material examined:Six specimens. Holotype,KIZ1994000011, paratypes, KIZ1994000012-16, 37.5-42.2 mm SL; subterranean water outlet near Bao’an Town,Du’an County, Guangxi, China, N24.1008°, E107.8631°,Hongshui River, a Pearl River tributary.

Diagnosis:No pigmentation and no eyes; caudal fin with 14 or 15 branched rays; body colorless.

Description:Body compressed laterally. Dorsal fin with 3 simple and 7-8 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 11-12 branched rays; pelvic fin with 5 branched rays; caudal fin with 14-15 branched rays.Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis absent on upper jaw. Anterior and posterior nostrils closely set, anterior nostril tube-like.Eyes absent. Lateral line and cephalic lateral-line pores present.

Dorsal-fin origin farther from snout tip than from caudal-fin origin. Anal fin straight, tip not reaching base of caudal fin.Pelvic-fin origin anterior to dorsal-fin origin, tip of pelvic fin not reaching anus. Caudal-peduncle depth less than its length.Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins and head. Air bladder with two chambers,anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head yellow, without color pattern. Fins hyaline.

Distribution:Known from Hongshui River, a tributary of the Pearl River.

Remarks:Heminoemacheilus hyalinuscan be distinguished from other congeneric species by eyes absent and caudal fin with 14 or 15 branched rays.

Heminoemacheilus longibarbatus (Gan, Chen & Yang,2007)

Yunnanilus longibarbatus, Gan, Chen & Yang, 2007: 322, fig.1 (type locality: Gaoling Township, Du’an County, Guangxi,China).

(Figure 3H2; Supplementary Figure S2B, F)

Material examined:Seven specimens. Paratypes KIZ2003050248, 250, 252-254, 256-257, 42.1-58.2 mm SL;Gaoling Township, Du’an County, Guangxi, China, N24.0639°,E108.0533°, Hongshui River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; outer gill rakers absent and 12-13 inner gill rakers on first gill arch; processus dentiformis absent; lateral line and cephalic lateral-line pores absent.

Description:Body compressed laterally. Dorsal fin with 3 simple and 8-9 branched rays; anal fin with 3 simple and 5-6 branched rays; pectoral fin with 10-11 branched rays; pelvic fin with 6 branched rays; caudal fin with 16 branched rays.Outer gill rakers absent, 12-13 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis absent on upper jaw.Anterior and posterior nostrils closely set, anterior nostril tubelike. Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores absent.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 51%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank yellow, belly and lower part of flank yellowish. Dark brown spots form a vertical stripe along lateral line from posterior of eye to base of caudal fin, upper part of lateral line with minute,dark brown, irregular spots. Fins hyaline.

Distribution:Known from Hongshui River, a Pearl River tributary.

Remarks:Yunnaniluslongibarbatuspossesses typical characters ofHeminoemacheilus, i.e., anterior and posterior nostrils closely set, anterior one tube-like, check scaleless,and lips without papillae. The species can be distinguished from other congeneric species by lateral line and cephalic lateral-lines absent and outer gill rakers on first gill arch absent.

Heminoemacheilus zhengbaoshani Zhu & Cao, 1987

Heminoemacheilus zhengbaoshaniZhu & Cao, 1987: 324,figs. 1-4 (type locality: subterranean water outlet near Du’an County, Guangxi, China).

(Figure 3H3; Supplementary Figure S2D, G)

Material examined:Three specimens. GXNU10060163, 166,175, 71.6-81.6 mm SL; subterranean water outlet near Du’an County, Guangxi, China, N23.9192°, E108.1056°, Hongshui River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; one outer gill raker and 15-16 inner gill rakers on first gill arch; processus dentiformis present; lateral line and cephalic lateral-line pores present.

Description:Body compressed laterally. Dorsal fin with 3 simple and 7-9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 11-12 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 16-17 branched rays. One outer and 12-13 inner gill rakers on first gill arch.Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis present on upper jaw. Anterior and posterior nostrils closely set, anterior nostril tube-like.Eyes medium sized, eye diameter less than interorbital distance. Lateral line and cephalic lateral-line pores present.Cephalic lateral-line canals with 9-10 supraorbital, 3+9-10 infraorbital, 2+2 or 3+3 supratemporal, and 11-12 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 53%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body covered with embedded scales, except between pectoral fins. Air bladder with two chambers, anterior chamber in bony capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head dark brownish,without color pattern. Fins hyaline.

Distribution:Known from Hongshui River, a Pearl River tributary.

Remarks:Heminoemacheiluszhengbaoshanican be distinguished from other congeneric species by the lateral line and cephalic lateral-line pores present.

Micronemacheilus Rendahl, 1944

MicronemacheilusRendahl, 1944: 45 (type species:Nemacheilus cruciatusRendahl, 1944: 37).

Diagnosis:Lateral line incomplete. Anterior and posterior nostrils slightly separated (distance 1/5 of eye diameter),posterior nostril closer to anterior nostril than to eye. Mouth inferior. Cheeks scaleless. Median parts of upper and lower lips with one and two pairs of delicate papillae, respectively.Lower posterior margin of inter-opercular with 3-4 indentations. Body with 14-18 black bars from operculum to caudal peduncle.

Remarks:Rendahl (1944) establishedMicronemacheilusforNemacheilus cruciatusfrom Central Vietnam. However, reexamination ofM. cruciatusby Freyhof & Serov (2001)showed that it belonged toYunnanilus. Freyhof & Serov(2001) erectedTraccatichthysforNemacheilus taeniatusPellegrin & Chevey 1936 and includedM. pulcher(Nichols &Pope 1927) in this genus. Kottelat (2012, 2013) consideredMicronemacheilusto be valid. Zhang & Zhao (2016) also placedT. pulcher(Nichols & Pope 1927) andT. zispi(Prokofiev, 2004) inMicronemacheilus, but without providing additional reasoning. In this study, we follow Kottelat (2012,2013) and considerMicronemacheilusto be valid based on several characters, including large papillae in median portion of both lips, indentations along posterior margin of operculum,and color pattern.Micronemacheiluscan be distinguished fromTraccatichthysby anterior and posterior nostrils slightly separated (vs. closely set) and molecular analyses (Figure 1).

Micronemacheilus pulcherrimus (Yang, Chen & Lan, 2004)

Yunnanilus pulcherrimusYang, Chen & Lan, 2004: 112 (type locality: Du’an County, Guangxi, China, Hongshuihe River, a Pearl River tributary).

(Figure 3M; Supplementary Figure S3)

Material examined:Six specimens, paratypes,KIZ1999001786-1787, 2002003720, 3723, 5673-5674,38.5-47.8 mm SL; Du’an County, Guangxi, China, N23.9192°,E108.1056°, Hongshuihe River, a Pearl River tributary.

Diagnosis:Whole body covered with scales; pectoral fin with 8-10 branched rays; caudal fin with 16 branched rays; outer gill rakers absent, 11-12 inner gill rakers on first gill arch;processus dentiformis present; lateral line incomplete, not reaching end of pectoral fin when folded backwards. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye. Mouth inferior. One pair of papillae on median part of upper lip, two pairs of papillae on median part of lower lip. Lower posterior margin of operculum with four prominent indentations. Cheeks scaleless. Body with 14-18 black vertical bars from operculum to caudal peduncle.

Description:Body compressed laterally. Dorsal fin with 4 simple and 8-9 branched rays; anal fin with 3 simple and 5-6 branched rays; pectoral fin with 8-10 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 16 branched rays.Outer gill rakers absent, 11-12 inner gill rakers on first gill arch. Mouth inferior. Median part of upper lip with one pair of papillae, lower lip with two pairs of papillae. Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated,posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter greater than interorbital distance. Lateral line and cephalic lateral-line pores present. Cephalic lateral-line canals with 3-5 supraorbital, 3+8 infraorbital, 2+2 supratemporal, and 5 mandibular pores.

Predorsal length 50%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body covered with embedded scales. Cheeks scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin.Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish. Flank with 14-18 black vertical bars, 1-9 bars thin, 10-18 bars twice as wide as former bars. Spaces between bars wider than bars.Vertical black stripe along lateral line wider than pupil from eye to base of caudal fin. Fins hyaline.

Distribution:Guangxi, China, and Vietnam.

Remarks:Yunnaniluspulcherrimusis moved to

Micronemacheilusbased on the following characters: lips with papillae, lower posterior margin of opercula with four prominent indentations, cheeks scaleless, and body with 14-18 black vertical bars from operculum to caudal peduncle.Unfortunately, no specimens ofM. cruciatuswere available for this study, so we comparedM. pulcherrimuswith the description ofM. cruciatusby Freyhof & Serov (2001).Micronemacheilus pulcherrimusandM. cruciatusare difficult to distinguish from each other based on morphological characters alone, but their validity is supported by molecular data (Luo et al., 2019).

Paranemachilus Zhu, 1983

ParanemachilusZhu, 1983: 311 (type species:Paranemachilus genilepisZhu, 1983: 311).

Diagnosis:Lateral line incomplete. Anterior and posterior nostrils closely set, anterior one tube-like. Mouth inferior. Lips smooth. Cheeks scaled.

Remarks:HeminoemacheilusandParanemachilusshare similar body shape, anterior and posterior nostrils closely set,and incomplete lateral line. However,Paranemachiluscan be distinguished fromHeminoemacheilusby cheeks covered with scales (vs. scaleless).Yunnanilus jinxiensisZhu, Du, Chen &Yang 2009 is referred toParanemachilusbased on cheeks scaled and anterior and posterior nostrils closely set.

Key to species of Paranemachilus

Paranemachilus genilepis Zhu, 1983

Paranemachilus genilepisZhu, 1983: 311, figs. 1-4 (type locality: Fusui County, Guangxi, China).(Figure 3P1; Supplementary Figure S4C)

Material examined:Five specimens, GXNU201908001-5,68.4-91.3 mm SL; Fusui County, Guangxi, China, N22.6353°,E107.9041°, Hongshuihe River, a Pearl River tributary.

Diagnosis:Outer gill rakers absent, 18 inner gill rakers on first gill arch. Pectoral fin with 11-13 branched rays; pre-anal fin length 79%-82% SL; caudal-peduncle length less than its depth.

Description:Body compressed laterally. Dorsal fin with 3 simple and 7-9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 11-13 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 16-18 branched rays. Outer gill rakers absent, 18 inner gill rakers on first gill arch. Mouth inferior. Lips smooth. Anterior and posterior nostrils closely set, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital distance. Lateral line and cephalic lateral-line pores present. Cephalic lateralline canals with 11-12 supraorbital, 3+9-12 infraorbital, 3+3 supratemporal, and 10-11 mandibular pores.

Predorsal length 55%-58% SL. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus.Caudal-peduncle length less than its depth. Caudal fin emarginate.

Body, including cheeks, covered with embedded scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin.Intestines straight.

Color pattern in formalin:Back and upper part of flank dark brown, belly and lower part of flank yellow brown. Many small,irregular, dark brown spots on back. Many irregular, dark brown spots forming longitudinal stripe on both sides from head to caudal-peduncle base. Fins hyaline.

Distribution:Known from Pearl River basin.

Remarks:Paranemachilus genilepiscan be distinguished from other congeneric species by a combination of the following features: outer gill rakers on first gill arch absent (vs.present inP. pingguoensis), 18 inner gill rakers on first gill arch (vs. 14 inP. jinxiensis), pre-anal fin length 79%-82% SL(vs. 71%-77% inP. jinxiensis), and caudal-peduncle length 88%-98% of its depth (vs. 99%-113% inP. pingguoensisand 100%-130% inP. jinxiensis).

Paranemachilus jinxiensis (Zhu, Du &Chen, 2009)

Yunnanilus jinxiensisZhu, Du & Chen, in Zhu, Du, Chen &Yang, 2009: 196, fig. 1 (type locality: Ludong Village, Jinxi County, Guangxi, China).

(Figure 3P2; Supplementary Figure S4A)

Material examined:Holotype, KIZ2008008627, 61.6 mm SL,paratypes, KIZ2008008628, 8629, 8630, 8631, 49.9-59.2 mm SL; Ludong Village, Jinxi County, Guangxi, China, N23.1345°,E106.3041°, May 2008.

Diagnosis:Pectoral fin with 13-14 branched rays. Outer gill rakers absent, 14 inner gill rakers on first gill arch; pre-anal fin length 71%-77% SL; caudal-peduncle length larger than its depth.

Description:Body compressed laterally. Dorsal fin with 3 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 13-14 branched rays; pelvic fin with 7-8 branched rays; caudal fin with 17 branched rays.Outer gill rakers absent, 14 inner gill rakers on first gill arch.Mouth inferior. Lips smooth, with strong furrows. Anterior and posterior nostrils closely set, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital distance.Lateral line and cephalic lateral-line pores present. Cephalic lateral-line canals with 9 supraorbital, 3+9 infraorbital, 2+2 supratemporal, and 10 mandibular pores.

Predorsal length 53%-59% SL. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus.Caudal-peduncle length 100%-130% of its depth. Caudal fin emarginate.

Body, including cheeks, covered with embedded scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin.Intestines straight.

Color pattern in formalin:Back and upper part of flank dark brown, belly and lower part of flank brownish. Spots forming irregular, short bars along lateral line, flank and head with many short, dark brown bars. Fins hyaline.

Distribution:Known from Pearl River.

Remarks:Yunnanilus jinxiensispossesses typical characters ofParanemachilus, including anterior and posterior nostrils closely set and cheeks scaled. Hence, the species is moved toParanemachilusin this study. It can be distinguished from other congeneric species by the following combination of characters: outer gill rakers on first gill arch absent (vs.present inP. pingguoensis), 14 inner gill rakers on first gill arch (vs. 18 inP. genilepis), and pre-anal length 71%-77% of SL (vs. larger than 78% inP. pingguoensisandP. genilepis).

Paranemachilus pingguoensis Gan, 2013

Paranemachilus pingguoensis, Gan, 2013: 28-32, figs. 18, 19(type locality: Guohua Township, Pingguo County, Guangxi,China).

(Figure 3P3; Supplementary Figure S4B)

Material examined:Five specimens, GXNU20111001-5,55.1-65.0 mm SL; Guohua Township, Pingguo County,Guangxi, China, N23.3202°, E107.6037°, collected by J.H.Lan October 2011.

Diagnosis:Pectoral fin with 12-13 branched rays. Outer gill rakers present, 17 inner gill rakers on first gill arch; pre-anal fin length 78%-82% SL; caudal-peduncle length 99%-113% of its depth.

Description:Body compressed laterally. Dorsal fin with 3 simple and 8-9 branched rays; anal fin with 3 simple and 5-6 branched rays; pectoral fin with 12-13 branched rays; pelvic fin with 6 branched rays; caudal fin with 17-18 branched rays.One or two outer and 17 inner gill rakers on first gill arch.Mouth inferior. Lips smooth, with strong furrows. Anterior and posterior nostrils closely set, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital distance.Lateral line and cephalic lateral-line pores present. Cephalic lateral-line canals with 9-10 supraorbital, 3+11-12 infraorbital,3+3 supratemporal, and 11-12 mandibular pores.

Predorsal length 53%-58% SL. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus.Caudal-peduncle length 99%-113% of its depth. Caudal fin emarginate.

Body covered with embedded scales, cheeks scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin.Intestines straight.

Color pattern in formalin:Back and upper part of flank yellow brown, belly and lower part of flank yellow. Many small,irregular, dark brown spots on back. Many irregular spots forming bars along lateral line on both sides from head to base of caudal fin. Fins hyaline.

Distribution:Known from the Pearl River.

Remarks:Paranemachilus pingguoensiscan be distinguished from other congeneric species by outer gill rakers on first gill arch present.

Genus Yunnanilus Nichols, 1925

YunnanilusNichols, 1925: 1 (type species:NemacheiluspleurotaeniaRegan).

Diagnosis:Yunnanilusis easily distinguished from other nemacheilid loaches by inferior mouth, anterior and posterior nostrils slightly separated (distance greater than 2/5 of eye diameter), anterior nostril tube-like, without elongated barbellike structure. Cheek scaleless, lips smooth with furrows.Lateral line and cephalic lateral-line pores present.

Remarks:The genusYunnanilusis heterogenous. Yang &Chen (1995) divided the genus into anigromaculatusspecies group andpleurotaeniaspecies group. Subsequently, Kottelat(2012) considered that some species of thenigromaculatusspecies group belong toEonemachilus, and some species of thepleurotaeniaspecies group may belong toHeminoemacheilus. In this study, some species of thenigromaculatusspecies group are relocated toEonemachilus.Species formerly of thepleurotaeniaspecies group from Guangxi are relocated toHeminoemacheilus(Y. bailianensisandY. longibarbatus),Paranemachilus(Y. jinxiensis), andMicronemacheilus(Y. pulcherrimus), see above. The remaining species of this group are retained inYunnanilus.

Key to species of Yunnanilus

Yunnanilus analis Yang, 1990

Yunnanilus analisYang, in Chu & Chen, 1990: 19, fig. 14(type locality: Lake Xingyun, Jiangchuan County, Yunnan,China).

(Figure 3Y1; Supplementary Figure S5A)

Material examined:Two specimens. Holotype,KIZ1960000625, 37.7 mm SL, paratype, KIZ1960000626, 50.2 mm SL; Lake Xingyun, Jiangchuan County, Yunnan, China,N24.3378°, E102.7833°, April 1961.

Diagnosis:Body scaleless; eye diameter greater than interorbital width; outer gill raker absent and 8 inner gill rakers on first gill arch; processus dentiformis present. Snout length 26%-29% HL; caudal-peduncle length 162%-180% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 3 simple and 9 branched rays; anal fin with 3 simple and 6 branched rays;pectoral fin with 12 branched rays; pelvic fin with 7 branched rays; caudal fin with 15 branched rays. Outer gill rakers absent, 8 inner gill rakers on first gill arch. Mouth inferior. Lips smooth, lower lip with median incision, furrows on each side.Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior of eye than anterior nostril, anterior nostril tube-like. Eyes medium sized, eye diameter larger than interorbital width. Lateral line and cephalic lateral-line pores present. Cephalic lateral-line canals with 6 supraorbital, 3+6 infraorbital, 0 supratemporal, and 5 mandibular pores.

Predorsal length 56.7%-56.8% SL. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin close to anus. Caudalpeduncle length 162%-180% of its depth. Caudal fin emarginate.

Body scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Many small, irregular, dark brown spots on back and lateral body. Fins hyaline.

Distribution:Known from the Nanpanjiang River, a Pearl River tributary.

Remarks:Zheng (1989) recordedY. pleurotaeniain Xingyun Lake, while Yang (1990) described it as a different species,Y.analis. Kottelat (2012) suggested thatY. analiscould belong toHeminoemacheilus. However, the anterior and posterior nostrils are closely set in the genusHeminoemacheilus,whereas the anterior and posterior nostrils are slightly separated inY. analis. Therefore, we treatY. analisas a valid species in the genusYunnanilus.

Yunnanilus beipanjiangensis Li, Mao & Sun 1994

Yunnanilus beipanjiangensisLi, Mao & Sun, in Li, Mao, Sun &Lu, 1994: 370, fig. 1 (type locality: Xintun Village, Zhanyi County, Yunnan, China).

(Figure 3Y2; Supplementary Figure S5B)

Material examined:Holotype, FACQR9107016, 47.7 mm SL,paratype, FACQR9107017, 9 uncat, 48.0-84.9 mm SL; Xintun Village, Zhanyi County, Yunnan, China, N25.9314°,E103.9943°, July 1991.

Diagnosis:Body scaleless; eye diameter greater than interorbital width; outer gill rakers absent, 10 inner gill rakers on first gill arch; processus dentiformis present. Snout length 32%-39% HL; caudal-peduncle length 130%-197% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 3 simple and 8-9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 11 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 10 inner gill rakers on first gill arch. Mouth inferior. Lips smooth, lower lip with median incision, furrows on each side. Processus dentiformis present on upper jaw.Anterior and posterior nostrils slightly separated, anterior nostril tube-like. Eyes medium sized, eye diameter greater than interorbital width. Lateral line and cephalic lateral-line pores present. Cephalic lateral-line canals with 6 supraorbital,3+10 infraorbital, 2+2 supratemporal, and 9-10 mandibular pores.

Predorsal length 50%-55% SL. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus.Caudal-peduncle length 130%-197% of its depth. Caudal fin emarginate.

Body scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank yellow, belly and lower part of flank yellowish. Many small,twisting, dark brown bars on back and flank. Fins hyaline.

Distribution:Known from the Beipanjiang River, a Pearl River tributary.

Remarks:Yunnanilus beipanjiangensisis the only species recorded in the Beipanjiang River basin. InYunnanilus,Y.beipanjiangensisshares similar characters withY. analis,including whole body scaleless, eye diameter greater than interorbital width, less than 10 inner gill rakers on first gill arch but can be distinguished fromY. analisby snout length 32%-39% HL (vs. 26%-29%) and caudal peduncle depth 7%-9% SL (vs. 6.9%-7.0%).

Yunnanilus chuanheensis Jiang, Zhao, Du & Wang, 2021

Yunnanilus chuanheensisJiang, Zhao, Du & Wang, 2021: 1-5(type locality: Nanjian County, Yunnan, China).(Figure 3Y20)

Material examined:Holotype KIZ 2 016 007 379, 46.8 mm SL;Paratype KIZ2016007380-90, 35.4-49.4 mm SL; Nanjian County, Yunnan, China, N24.8687°, E102.4693°, Lixianjiang River, a Red River tributary.

Diagnosis:Body covered with scales; caudal fin with 16 branched rays; 12 inner gill rakers on first gill arch; processus dentiformis absent; eye diameter smaller than interorbital width; lateral line incomplete; caudal peduncle depth 17.8%-22.8% SL.

Description:Body elongated. Dorsal fin with 3 simple and 8-9 branched rays; anal fin with 3 simple and 5-6 branched rays; pectoral fin with 11-12 branched rays; pelvic fin with 7-8 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 10-11 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis absent on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital distance. Lateral line incomplete. Cephalic lateral-line canals with 8-9 supraorbital,3+11-12 infraorbital, 3+3 supratemporal, and 9-10 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 52.1%-59.4% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth larger than its length. Caudal fin emarginate.

Body covered with scales, except on ventral area between pectoral and pelvic fins. Air bladder with two chambers,anterior chamber in capsule, large posterior chamber free,filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish, large brown blotches irregularly distributed on dorsal and lateral body,connected to longitudinal black stripe on lateral line. Fins hyaline.

Distribution:Known from Chuanhe in the upper reaches of the Lixianjiang River, a Pearl River tributary.

Remarks:Yunnanilus chuanheensisis the first species ofYunnanilusrecorded in Red River. It can be distinguished from other congeneric species by body scaled (vs. scaleless or only caudal peduncle scaled inY. analis,Y.beipanjiangensis,Y. chui,Y. discoloris,Y. elakatis,Y.macrositanus,Y. nanpanjiangensis,Y. paludosusandY.sichuanensis), eye diameter smaller than interorbital distance(vs. larger inY. jiuchiensisandY. longibulla), 10-11 inner gill rakers on first gill arch (vs. 8-9 inY. parvus), and processus dentiformis absent (vs. present inY. pleurotaenia).

Yunnanilus chui Yang, 1991

Yunnanilus chuiYang, 1991: 199, fig. 3 (type locality: Lake Fuxian, Chengjiang County, Yunnan, China).

(Figure 3Y3; Supplementary Figure S5C)

Material examined:Paratype KIZ1989001596, 36.2 mm SL;Lake Fuxian, Chengjiang County, Yunnan, China, N24.5201°,E102.9378°, Nanpanjiang River, a Pearl River tributary.

Diagnosis:Body scaleless; pectoral fin with 11 branched rays; caudal fin with 16 branched rays; 12 inner gill rakers on first gill arch; processus dentiformis present; lateral line incomplete, with 4 pores.

Description:Body elongated. Dorsal fin with 4 simple and 9 branched rays; anal fin with 3 simple and 6 branched rays;pectoral fin with 11 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 15 inner gill rakers on first gill arch. Mouth inferior;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter greater than interorbital distance. Lateral line incomplete, with 4 pores, cephalic lateral-line pores degenerated, only 2-3 infraorbital pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 53% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish, vertical twisted bars on flank along lateral line, especially posterior 2/3 of flank, space between bars wider than bars. Fins hyaline.

Distribution:Known from Lake Fuxian, the Nanpanjiang River, a Pearl River tributary.

Remarks:Kottelat (2012) suggested thatY. chuimay belong toEonemachilus. However,Y. chuihas a short lateral line and degenerated cephalic lateral-line pores, which are not typical characters ofEonemachilus.Yunnanilus chuican be separated from other congeneric species by scaleless body and eye diameter greater than interorbital distance, 12 inner gill rakers on first gill arch, cephalic lateral-line degenerated.

Yunnanilus discoloris Zhou & He, 1989

Yunnanilus discolorisZhou & He, 1989: 381, fig. 1 (type locality: White Dragon Spring, Chenggong County, Yunnan,China).

(Figure 3Y4; Supplementary Figure S5D-E)

Material examined:Six specimens, paratypes,KIZ1983000938, 939, 940, 941, 942, 943, 21.6-31.4 mm SL;White Dragon Spring, Chenggong County, Yunnan, China,N24.8709°, E102.8559°, October 1983.

Diagnosis:Body scaleless; eye diameter equal to interorbital width; processus dentiformis absent; upper lip smooth, lower lip with median incision, furrows on each side. Eye diameter 27%-31% HL; interorbital width 18%-25% HL; caudalpeduncle length 154%-189% of its depth. Caudal fin forked,with 14 branched rays.

Description:Body elongated. Dorsal fin with 4 simple and 8-9 branched rays; anal fin with 3 simple and 5 branched rays; pectoral fin with 11-12 branched rays; pelvic fin with 7 branched rays; caudal fin with 14 branched rays. Outer gill rakers absent, 8-10 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis absent on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter equal with interorbital width. Lateral line incomplete,with 4-10 pores. Cephalic lateral-line canals with 9 supraorbital, 3+13 infraorbital, 2+2 supratemporal, and 12 mandibular pores.

Dorsal-fin origin close to middle of snout tip and caudal-fin origin, predorsal length 48%-54% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle length 154%-189% of its depth. Caudal fin forked.

Body scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish. Black longitudinal stripe along lateral line wider than pupil from posterior operculum to base of caudal fin on both sides in males, black blotches along lateral line on both sides in females. Fins hyaline.

Distribution:Known from the White Dragon Spring, Jinsha River basin.

Remarks:InYunnanilus,Y. discoloris,Y. analis,Y.beipanjiangensis,Y. chui,Y. paludosusshare scaleless body.However,Y. discoloriscan be separated from these congeneric species by caudal fin forked (vs. emarginate) and processus dentiformis absent (vs. present).

Yunnanilus elakatis Cao & Zhu, 1989

Yunnanilus elakatisCao & Zhu, in Zheng, 1989: 43, fig. 21(type locality: Yiliang County, Yunnan, China).(Figure 3Y5)

Material examined:No specimens. Data from original description.

Diagnosis:Body scaleless, except caudal peduncle; eye diameter smaller than interorbital width; 10-12 inner gill rakers on first gill arch; processus dentiformis present. Eye diameter 20%-26% HL; interorbital width 26%-35% HL; caudalpeduncle length 90%-100% of its depth.

Description:Body elongated. Dorsal fin with 3 simple and 9-10 branched rays; anal fin with 2 simple and 5-6 branched rays; pectoral fin with 10-11 branched rays; pelvic fin with 7-8 branched rays; caudal fin with 16 branched rays. Outer gill rakers unknown, 10-12 inner gill rakers on first gill arch.Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis present on upper jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital distance.Lateral line incomplete.

Dorsal-fin origin located in middle between snout tip and caudal-fin origin. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudal-peduncle length 90%-100% of its depth. Caudal fin emarginate. Body scaleless, except caudal peduncle.

Color pattern in formalin:Body and head brownish, 5-7 and 5-6 dark brown bars before and after dorsal fin, respectively.Lateral body covered with minute, dark brown, irregular blotches. Fins hyaline.

Distribution. Known from the Nanpanjiang River, N24.9209°,E103.1419°, a Pearl River tributary.

Remarks:InYunnanilus,Y. elakatis,Y. macrositanus,Y.nanpanjiangensis, andY. sichuanensisshare body scaleless,except on caudal peduncle. However,Y. elakatiscan be distinguished fromY. macrositanusandY. nanpanjiangensisby caudal-peduncle length 90%-100% of its depth (vs. larger than 130%) and fromY. sichuanensisby processus dentiformis present (vs. absent).

Yunnanilus forkicaudalis Li, 1999

Yunnanilus forkicaudalisLi, in Li, Wu, Xu, Gao, Chen, Wu &Wang, 1999: 4, fig. 2 (type locality: Heilongtan reservoir, Shilin County, Yunnan, China).(Figure 3Y6)

Material examined:No specimens. Data from original description.

Diagnosis:Body scaleless; eye diameter smaller than interorbital width; one outer and 12 inner gill rakers on first gill arch. Lateral head length 22%-26% SL; caudal peduncle depth 8%-10% SL; snout length 37%-44% HL; eye diameter 13%-17% HL; interorbital width 25%-28% HL; caudalpeduncle length 120%-180% of its depth. Caudal fin forked.

Description:Body elongated. Dorsal fin with 3 simple and 7 branched rays; anal fin with 2 simple and 5 branched rays;pectoral fin with 9-11 branched rays; pelvic fin with 8 branched rays; caudal fin with 16 branched rays. One outer and 8 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital distance.Lateral line incomplete.

Dorsal-fin origin closer to snout tip than caudal-fin base.Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudal-peduncle length 120%-180% of its depth. Caudal fin forked.

Body scaleless, except caudal peduncle. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Eight dark brown blotches extending from dorsal to midline body, eight dark brown blotches on lower midline body. Fins hyaline.

Distribution:Known from Heilongtan reservoir, N24.7651°,E103.3046°, Nanpanjiang River, a Pearl River tributary.

Remarks:Kottelat (2012) treatedY. forkicaudalisas a junior synonym ofY. macrositanus, but Du et al. (2018) compared the original descriptions and treatedY. forkicaudalisas a valid species.Yunnanilus forkicaudaliscan be distinguished fromY.macrositanusby whole body scaleless (vs. caudal-peduncle scaled), 12 inner gill rakers on first gill arch (vs. 8), and interorbital width 25%-28% HL (vs. 30%-36%).

Yunnanilus jiuchiensis Du, Hou, Chen & Yang, 2018

Yunnanilus jiuchiensisDu, Hou, Chen & Yang, 2018:137-144, fig. 1 (type locality: Jiuchi County, Penzhou City,Sichuan, China).

(Figure 3Y8; Supplementary Figure S5F-G)

Material examined:Holotype, KIZ2018000002, 35.3 mm SL,paratype, KIZ2018000001, 0003-9, 29.6-37.4 mm SL; Jiuchi County, Penzhou City, Sichuan, China, N30.9876°,E104.0484°, March 2018.

Diagnosis:Whole body covered with scales; eye diameter greater than interorbital width; processus dentiformis absent;pectoral fin with 11 branched rays. Outer gill rakers absent, 8 inner gill rakers on first gill arch; upper lip smooth, lower lip with median incision, furrows on each side. Body depth 17%-21% SL; lateral head length 25%-28% SL; eye diameter 22%-28% HL; interorbital width 20%-24% HL; caudalpeduncle length 78%-99% of its depth. Caudal fin emarginate.

Description:Body slender. Dorsal fin with 3 simple and 8 branched rays; anal fin with 3 simple and 6 branched rays;pectoral fin with 11 branched rays; pelvic fin with 6 branched rays; caudal fin with 15-16 branched rays. Outer gill rakers absent, 8 inner gill rakers on first gill arch. Mouth inferior;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis absent. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter greater than interorbital distance. Lateral line incomplete. Cephalic lateral-line canals with 6-7 supraorbital,3+12 infraorbital, 2+2 supratemporal, and 6-10 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 52%-57% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle length 78%-99% of its depth. Caudal fin emarginate.

Whole body covered with scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Upper 2/3 of body and head covered with brown blotches in females, longitudinal stripe along lateral line in males. Fins hyaline.

Distribution:Known from Tuojiang River, Yangtze River basin.

Remarks:Yunnanilus jiuchiensisandY. sichuanensisare recorded in Sichuan Province.Yunnanensis jiuchiensiscan be distinguished fromY. sichuanensisby whole body covered with scales (vs. posterior body), eye diameter greater than interorbital width (vs. smaller), and interorbital width 20%-24%HL (vs. 36%-46%).

Yunnanilus longibulla Yang, 1990

Yunnanilus longibullaYang, 1990: 21, fig. 16 (type locality:Lake Chenghai, Yongsheng County, Yunnan, China).(Figure 3Y9; Supplementary Figure S5P)

Material examined:Holotype, KIZ1981002383, 41.0 mm SL,paratype, KIZ1981002384-2 386, 2 388-2 393, 28.6-37.0 mm SL; Lake Chenghai, Yongsheng County, Yunnan, China,N26.5466°, E100.6647°, August 1981.

Diagnosis:Whole body covered with scales; eye diameter greater than interorbital width; processus dentiformis present;pectoral fin with 11 branched rays. Outer gill raker absent, 8 inner gill rakers on first gill arch; upper lip smooth, lower lip with median incision, furrows on each side. Cephalic lateralline canals with 7 supraorbital, 4+9 infraorbital, 3+3 supratemporal, and 8-9 mandibular pores. Body depth 17%-21% SL; lateral head length 25%-28% SL; eye diameter 24%-32% HL; interorbital width 17%-23% HL; caudalpeduncle length 111%-166% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 11 branched rays; pelvic fin with 7 branched rays; caudal fin with 17 branched rays. Outer gill rakers absent, 10-12 inner gill rakers on first gill arch. Mouth inferior;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter greater than interorbital distance. Lateral line incomplete, with 11-17 pores. Cephalic lateral-line canals with 7 supraorbital, 4+9 infraorbital, 3+3 supratemporal, and 8-9 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 50%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body covered with scales. Air bladder with two chambers,anterior chamber in capsule, large posterior chamber free,filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish. Ten to twelve round, dark brown spots along lateral line in females,longitudinal stripe along lateral line in males. Back and head covered with brown blotches. Fins hyaline

Distribution:Known from Lake Chenghai, Yangtze River basin.

Remarks:InYunnanilus,Y. longibulla,Y. jiuchiensis,Y.macrogaster,Y. macrolepis,Y. parvus,Y. pleurotaenia, andY.spanisbripesshare whole body covered with scales. However,Y. longibullacan be distinguished from these species by eye diameter greater than interorbital width (vs. smaller inY.macrogaster,Y. macrolepis,Y. parvus,Y. pleurotaenia, andY.spanisbripes), 17 branched caudal fins (vs. 15-16 in others),outer gill rakers absent (vs. present inY. macrolepisandY.spanisbripes), and 10-12 inner gill rakers on first gill arch (vs.8-9 inY. parvusandY. jiuchiensis).

Yunnanilus macrogaster Kottelat & Chu, 1988

Yunnanilus macrogasterKottelat & Chu, 1988: 81, fig. 17(type locality: Datangzi Village, Luoping County, Yunnan,China).

(Figure 3Y10; Supplementary Figure S5H)

Material examined:Holotype, KIZ1980004273, 70.1 mm SL,paratype, KIZ1980004274, 70.1 mm SL; Datangzi Village,Luoping County, Yunnan, China, N24.6563°, E104.3663°,June 1980.

Diagnosis:Whole body covered with scales; eye diameter smaller than interorbital width; processus dentiformis present;pectoral fin with 12-13 branched rays. Outer gill rakers absent, 13 inner gill rakers on first gill arch; upper lip smooth,lower lip with median incision, furrows on each side. Cephalic lateral-line canals with 9 supraorbital, 4+10 infraorbital, 3+3 supratemporal, and 11 mandibular pores. Body depth 22%-23% SL; lateral head length 25%-26% SL; eye diameter 11.9%-12.0% HL; interorbital width 26%-27% HL; caudalpeduncle length 121%-137% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 12-13 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 13 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital width. Lateral line incomplete, with 12-13 pores. Cephalic lateral-line canals with 9 supraorbital, 4+10 infraorbital, 3+3 supratemporal, and 11 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 55%-56% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body covered with scales. Air bladder with two chambers,anterior chamber in capsule, large posterior chamber free,filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head yellowish brown with irregularly distributed dark brown spots on upper twothirds. Fins hyaline.

Distribution:Known from the Nanpanjiang River.

Remarks:InYunnanilus,Y. macrogaster,Y. macrolepis,Y.pleurotaeniaandY. spanisbripesshare whole body covered with scales and eye diameter smaller than interorbital width.However,Y. macrogastercan be separated from other species by pectoral fin with 12-13 branched rays (vs. 10-11 in others), body depth 22%-23% SL (vs. 17%-22% inY.pleurotaenia, 16%-22% inY. spanisbripes), caudal-peduncle length 12.7%-12.8 SL (vs. 11%-12% inY. macrolepis), eye dimeter 11.9%-12.0% HL (vs. 13%-18% inY. macrolepis,18%-21% inY. pleurotaenia, 17%-22% inY. spanisbripes).

Yunnanilus macrolepis Li, Tao & Mao, 2000

Yunnanilus macrolepisLi, Tao & Mao, in Li, Tao, Mao & Lu,2000: 349, fig. 1 (type locality: Xuetian Dragon Spring,Luoping County, Yunnan, China).

(Figure 3Y12; Supplementary Figure S5I)

Material examined:Five specimens, HRAS9509001,9509003, 9506997 and 2 uncat., Xuetian Dragon Spring,Luoping County, Yunnan, China, N24.8843°, E104.3461°,September 1995.

Diagnosis:Whole body covered with scales; eye diameter smaller than interorbital width; processus dentiformis present;pectoral fin with 10-11 branched rays. One or two rakers and 14-15 inner gill rakers on first gill arch; upper lip smooth,lower lip with median incision, furrows on each side. Cephalic lateral-line canals with 9-10 supraorbital, 3+15 infraorbital,4+2 supratemporal, and 10-14 mandibular pores. Body depth 19%-25% SL; lateral head length 23%-26% SL; eye diameter 13%-18% HL; interorbital width 21%-28% HL; caudalpeduncle length 106%-119% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 8-9 branched rays; anal fin with 3 simple and 6 branched rays; pectoral fin with 10-11 branched rays; pelvic fin with 6 branched rays; caudal fin with 15-16 branched rays. One or two outer and 14-15 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital. Lateral line incomplete, with 9-17 pores. Cephalic lateral-line canals with 9-10 supraorbital, 3+15 infraorbital, 4+2 supratemporal, and 10-14 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 55%-58% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body covered with scales. Air bladder with two chambers,anterior chamber in capsule, large posterior chamber free,filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank yellow brown, belly and lower part of flank yellow. Two lines longitudinal stripes formed by round dark brown spots along lateral line. Back and head covered with irregularly distributed dark brown spots. Dorsal fin with brown spots, other fins hyaline.

Distribution:Known from Xuetian Dragon Spring,Nanpanjiang River basin.

Remarks:Kottelat (2012) treatedY. macrolepisas a junior synonym ofY. paludosus. Du et al. (2018) treatedY.macrolepisas a valid species based on body covered with scales (vs. scaleless). In addition,Y. macrolepiscan be distinguished fromY. paludosusby 1-2 outer gill rakers on first gill arch (vs. absent), 14-15 inner gill rakers on first gill arch (vs. 12), body depth 19%-25% SL (vs. 16%-17%),lateral head length 23%-26% SL (vs. 20%-21%), caudalpeduncle length 11%-12% SL (vs. 14%-16%), and caudal peduncle depth 10%-12% SL (vs. 7%-8%).

Yunnanilus macrositanus Li, 1999

Yunnanilus macrositanusLi, in Li, Wu, Xu, Gao, Chen, Wu &Wang, 1999: 4, fig. 1 (type locality: Heilongtan reservoir, Shilin County, Yunnan, China).(Figure 3Y11)

Material examined:No specimen. Data from original description.

Diagnosis:Posterior body covered with scales; eye diameter smaller than interorbital width; pectoral fin with11 branched rays. One outer and 8 inner gill rakers on first gill arch. Body depth 20%-21% SL; eye diameter 15%-18% HL; interorbital width 30%-36% HL; caudal-peduncle length 140% of its depth. Caudal fin forked.

Description:Body elongated. Dorsal fin with 3 simple and 7 branched rays; anal fin with 2 simple and 5 branched rays;pectoral fin with 11 branched rays; pelvic fin with 8 branched rays; caudal fin with 16-17 branched rays. One outer gill raker and eight inner gill rakers on first gill arch. Mouth inferior;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis absent on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital width. Lateral line incomplete, cephalic lateral-line pores unknown.

Dorsal-fin origin closer to snout tip than from caudal-fin origin. Anal fin straight, tip not reaching base of caudal fin.Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudal-peduncle depth less than its length.Caudal fin slightly forked.

Posterior body covered with scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head yellowish brown.Eight dark brown blotches extending from dorsal to midline body, eight dark brown blotches on lower midline. Fins hyaline.

Distribution:Known from Heilongtan reserivor, N24.7651°,E103.3046°, Nanpanjiang River basin.

Remarks:Li et al. (1999) used three different species spellings in the original description, i.e.,macrositanus,macroistainus, andmacroistanus. Kottelat (2012) treatedmacrositanusas the correct original spelling, and further treatedY. forkicaudalisas a junior synonym toY.macrositanus. Here, however, we treatY. forkicaudalisas a valid species, as discussed above.

Yunnanilus nanpanjiangensis Li, Tao & Lu, 1994

Yunnanilus nanpanjiangensisLi, Mao & Lu, in Li, Mao, Sun &Lu, 1994: 371, fig. 2 (type locality: Agang Township, Luoping County, Yunnan, China).(Figure 3Y13; Supplementary Figure S5J)

Material examined:Six specimens, FACQR9191108, 13-14,22, 29, 34, 50.5-67.4 mm SL; Agang Township, Luoping County, Yunnan, China, N25.0765°, E104.1091°, September 1991.

Diagnosis:Body scaleless, except caudal peduncle; eye diameter smaller than interorbital width; outer gill rakers absent, 10 inner gill rakers on first gill arch; upper lip smooth,lower lip with median incision, furrows on each side;processus dentiformis present; pectoral fin with 10 branched rays. Body depth 23%-25% SL; eye diameter 17%-20% HL;interorbital width 19%-24% HL; caudal-peduncle length 133%-171% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 8-9 branched rays; anal fin with 3 simple and 6 branched rays; pectoral fin with 10 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 10 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital width. Lateral line incomplete, with 6-10 pores. Cephalic lateral-line canals with 8-9 supraorbital, 3+12 infraorbital, 3+3 supratemporal, and 10 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 51%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body scaleless, except for caudal peduncle. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank yellow brown. Body and head covered with irregularly distributed dark brown pigments on upper 2/3 of body. Fins hyaline.

Distribution:Known from the Nanpanjiang River basin.

Remarks:Yunnanilus nanpanjiangensis,Y. elakatis, andY.macrositanusshare scaleless body, except for caudal peduncle. However,Y. nanpanjiangensiscan be separated fromY. elakatisandY. macrositanusby interorbital 19%-24%HL (vs. greater than 25% inY. elakatisandY. macrositanus).Furthermore,Y. nanpanjiangensiscan be separated fromY.macrositanusby outer gill rakers on first gill arch absent (vs.present) and fromY. elakatisby caudal-peduncle length 133%-171% of its depth (vs. 90%-100%).

Yunnanilus paludosus Kottelat & Chu, 1988

Yunnanilus paludosusKottelat & Chu, 1988: 76, fig. 12 (type locality: Luoping County, Yunnan, China).(Figure 3Y14; Supplementary Figure S5K)

Material examined:Five specimens, paratypes,KIZ1980001277-1 281, 56.8-74.3 mm SL; Luoping County,Yunnan, China, N24.9142°, E104.2835°, June 1980.

Diagnosis:Eye diameter smaller than interorbital width; outer gill rakers absent, 12 inner gill rakers on first gill arch;processus dentiformis present. Lateral head length 20%-21%SL; caudal peduncle depth 7%-8% SL; snout length 32%-42% HL; eye diameter 15%-18% HL; interorbital width 17%-22% HL; caudal-peduncle length 182%-222% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5-6 branched rays;pectoral fin with 9-11 branched rays; pelvic fin with 6-7 branched rays; caudal fin with 14-16 branched rays. Outer gill rakers absent, 12 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital width. Lateral line incomplete, with 19-21 pores. Cephalic lateral-line canals with 6-7 supraorbital, 3+8 infraorbital, 3+3 supratemporal, and 6-11 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 50%-54% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Body scaleless. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brownish, belly and lower part of flank gray, back and flank covered with irregular, round, brown spots. Fins hyaline.Distribution:Known from the Nanpanjiang River basin.Remarks:InYunnanilus,Y. paludosus,Y. analis,Y.beipanjiangensis,Y. discoloris, andY. forkicaudalisshare scaleless body, butY. paludosuscan be distinguished from these species by caudal fin emarginate (vs. forked inY.discolorisandY. forkicaudalis), 12 inner gill rakers on first gill arch (vs. 8-10 inY. analisandY. beipanjiangensis), and lateral head length 20%-21% SL (vs. 27% inY. chui).

Yunnanilus parvus Kottelat & Chu, 1988

Yunnanilus parvusKottelat & Chu, 1988: 77, fig. 13 (type locality: Nantong cave, Kaiyuan County, Yunnan, China).

(Figure 3Y15; Supplementary Figure S5L)

Material examined:Holotype, KIZ1984001244, 25.1 mm SL,paratypes, KIZ1984001246, 1248, 1251, 1252, 1253, 1257,26.7-33.5 mm SL; Nantong cave, Kaiyuan County, Yunnan,China, N23.6482°, E103.2875°, July 1984.

Diagnosis:Whole body covered with scales; eye diameter smaller than interorbital width; processus dentiformis present;pectoral fin with 10-11 branched rays. Outer gill rakers absent, 8-9 inner gill rakers on first gill arch; upper lip smooth,lower lip with median incision, furrows on each side. Body depth 21%-23% SL; lateral head length 25%-28% SL; eye diameter 21%-27% HL; interorbital width 24%-28% HL;caudal-peduncle length 97%-113% of its depth. Caudal fin emarginate.

Description:Body slender. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 10-11 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 8-9 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital width. Lateral line incomplete, with 7-16 pores. Cephalic lateral-line canals with 5-7 supraorbital, 3+8 infraorbital, 3+3 supratemporal, and 5 mandibular pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 52%-54% SL. Anal fin straight, tip reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin reaching anus. Caudalpeduncle length 97%-113% of its depth. Caudal fin emarginate.

Body covered with scales. Air bladder with two chambers,anterior chamber in capsule, large posterior chamber free,filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish. Nine or ten round spots along lateral line on each side. Fins hyaline.

Distribution:Known from the Nanpanjiang River basin.

Remarks:InYunnanilus,Y. parvus,Y. macrogaster,Y.macrolepis,Y. pleurotaenia,Y.spanisbripes,Y. longibulla,andY. jiuchiensisshare whole body covered with scales.However,Y. parvuscan be distinguished from congeneric species by outer gill rakers on first gill arch absent (vs. present inY. macrolepis, andY. spanisbripes), 8-9 inner gill rakers on first gill arch (vs. more than 10 inY. macrogaster,Y.pleurotaenia, andY. longibulla), predorsal length 52%-54%SL (vs. 55%-58% inY. macrolepis), eye diameter 21%-27%HL (vs. smaller than 20% inY. macrogasterandY.macrolepis).

Yunnanilus pleurotaenia (Regan, 1904)

Nemachilus pleurotaeniaRegan, 1904: 192 (type locality:Lake Dianchi, Kunming City, Yunnan, China)

Yunnanilus pleurotaenia, Zheng, 1989: 42 (lakes Xingyun,Fuxian, Dianchi and Chenghai); Zhu, 1989: 15-17, fig. 7(Lakes Xingyun, Fuxian, Dianchi, Er’Hai and Chenghai).

Yunnanilus tigerivinusLi & Duan, 1999: 254, fig. 1 (type locality: suburbs of Kunming, Yunnan, China). Kottelat, 2012:136.

(Figure 3Y16; Supplementary Figure S5M, N)

Material examined:Lectotype, BMNH1904.1.26.36 Yunnan fu = Lake Dianchi. KIZ 20004050, 4053, 4054, 4061, 4063,4069, 4071, 4072, 4074, 41.8-63.4 mm SL; Green Dragon Spring, Kunming City, Yunnan, N25.3012°, E102.8894°, April 1999. KIZ2016007357-7386, 46.9-59.1 mm SL; Yousuo Village, Eryuan County, Dali City, Yunnan, N26.0201°,E100.0621°, December 2016. KIZ1988003256-3259, Lake Fuxian, Chengjiang County, Yuxi City, Yunnan, N24.5201°,E102.9378°, November 1988.

Diagnosis:Whole body covered with scales; eye diameter smaller than interorbital width; processus dentiformis present;pectoral fin with 10 branched rays. Outer gill rakers absent,10-13 inner gill rakers on first gill arch; upper lip smooth,lower lip with median incision, furrows on each side. Body depth 17%-22% SL; lateral head length 23%-26% SL; eye diameter 18%-21% HL; interorbital width 25%-33% HL;caudal-peduncle length 104%-132% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 10 branched rays; pelvic fin with 6 branched rays; caudal fin with 15-16 branched rays. Outer gill rakers absent, 10-13 inner gill rakers on first gill arch. Mouth inferior;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital width. Lateral line incomplete, with 16-25 pores. Cephalic lateral-line canals with 7-8 supraorbital, 4+9-10 infraorbital, 3+3 supratemporal, and 6-9 mandibular pores.

Predorsal length 48%-55% SL. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin close to anus. Caudalpeduncle length 104%-132% of its depth. Caudal fin emarginate.

Whole body covered with scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank dark brown, belly and lower part of flank brown. Longitudinal stripe along lateral line wider than eye diameter from posterior of operculum to base of caudal fin in males, many bars or spots along lateral line in females. Back covered with large,irregular, dark brown blotches. Fins hyaline.

Distribution:Known from the Jinsha and Lancang Rivers basin.

Remarks:Species ofYunnanilus, exceptY. pleurotaenia, are limited to small water bodies.Yunnanilus pleurotaeniawas first recorded in Lake Dianchi, Yunnan (Jinsha River basin) by Regan (1904). Chaudhuri (1911) recorded the species in Dali City, Yunnan (Lancang River basin). Zheng (1989) recordedY. pleurotaeniain the Nanpanjiang River basin (lakes Xingyun and Fuxian) and Jinsha River basin (lakesDianchi and Chenghai). In later studies, specimens determined asY.pleurotaeniafrom Lake Xingyun and Lake Chenghai were described asY. analisandY. longibulla, respectively (Yang,1990). The specimens from Dali and Lake Fuxian are difficult to distinguish fromY. pleurotaeniaas they share a similar body shape, number of branched rays, and most meristic characters. Hence, the specimens from Dali and Lake Fuxian are identified here asY. pleurotaenia.

Yunnanilus retrodorsalis (Lan, Yang et Chen, 1995)

Oreonectes retrodorsalisLan, Yang et Chen, 1995: 366 (type locality: Liuzai Township, Nandan County, Guangxi, China);Du et al., 2008: 32.

Yunnanilus retrodorsalis, Lan et al., 2013: 40-44; Zhang et al.,2016: 150.

(Figure 3Y17; Supplementary Figure S5Q)

Material examined:Seven specimens. Holotype,KIZ1991003951, paratypes, KIZ1991003952-3956, 26.0-38.4 mm SL; Liuzai Township, Nandan County, Guangxi, China,N25.2961°, E107.4044°.

Diagnosis:Whole body covered with scales, except head;eye diameter greater than interorbital width. Outer gill rakers absent, 10-13 inner gill rakers on first gill arch. Cephalic lateral-line pores reduced, with only 2+4 infraorbital pores.

Description:Body compressed laterally. Dorsal fin with 4 simple and 7 branched rays; anal fin with 4 simple and 5 branched rays; pectoral fin with 10 branched rays; pelvic fin with 7 branched rays; caudal fin with 14 branched rays. Outer gill rakers absent, 10-13 inner gill rakers on first gill arch.Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis absent on upper jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter greater than interorbital width.Lateral line incomplete, with 3-4 pores. Cephalic lateral-line pores reduced, with only 2+4 infraorbital pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin. Anal fin straight, tip not reaching base of caudal-fin origin. Pelvic-fin origin slightly anterior to dorsal-fin origin, tip of pelvic fin not reaching anus. Caudal-peduncle depth less than its length. Caudal fin emarginate.

Body covered with scales. Air bladder with two chambers,anterior chamber in capsule, large posterior chamber free,filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank brownish. Without clear color pattern. Fins hyaline.

Distribution:Known from the Pearl River basin.

Remarks:Yunnanilus parvus,Y. macrogaster,Y. macrolepis,Y. pleurotaenia,Y. spanisbripes, andY. retrodorsalisshare entire body scaled and eye diameter greater than interorbital width. However,Y. retrodorsaliscan be distinguished from these congeneric species by caudal fin with 14 branched rays(vs. 15-16 in other species) and cephalic lateral line pores reduced (vs. developed). Other distinguishing characters:outer gill rakers on first gill arch absent (vs. present inY.macrolepisandY. spanisbripes), inner gill rakers more than 10 (vs. 8-9 inY. parvus), body depth 15%-19% SL (vs.22%-23% inY. macrogaster), caudal peduncle depth 7%-9%SL (vs. 9.7%-11.4% inY. pleurotaenia).

Yunnanilus sichuanensis Ding, 1995

Yunnanilus sichuanensisDing, 1995: 253, fig. 1 (type locality:Anning River, Mianning County, Sichuan, China).(Figure 3Y18)

Material examined:No specimens. Data from original description.

Diagnosis:Posterior body covered with scales; eye diameter smaller than interorbital width; processus dentiformis absent;pectoral fin with 12 branched rays. Outer gill rakers absent,9-10 inner gill rakers on first gill arch. Body depth 20%-22%SL; eye diameter 25%-30% HL; interorbital width 36%-46%HL; caudal-peduncle length 90%-100% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 3 simple and 8 branched rays; anal fin with 3 simple and 5 branched rays;pectoral fin with 12 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays. Outer gill rakers absent, 9-10 inner gill rakers on first gill arch. Mouth inferior;upper lip smooth, lower lip thick, with strong furrows.Processus dentiformis absent on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated, posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital. Lateral line incomplete, with 16-17 pores.

Dorsal-fin origin farther from snout tip than from caudal-fin origin, predorsal length 56%-63% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Posterior body covered with scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Body and head yellowish, covered with irregular dark brown blotches. Black longitudinal stripe from gill aperture to base of caudal peduncle, 16-19 and 20-26 dark brown blotches on upper and lower longitudinal bars, respectively. Base of dorsal fin with small, black spot,other fins hyaline.

Distribution:Known from the Anning River, N28.5513°,E102.1810°, Yangtze River basin.

Remarks:Yunnanilus sichuanensiscan be distinguished from other congeneric species by posterior part of body covered with scales. Furthermore,Y. sichuanensiscan be distinguished fromY. macrositanus,Y. forkicaudalis, andY.discolorisby emarginate caudal fin (vs. forked), fromY.macrolepisandY. spanisbripesby outer gill rakers on first gill arch absent (vs. present), fromY. elakatis,Y. paludosus,Y.macrogaster,Y. chui,Y. pleurotaenia, andY. longibullaby 9-10 inner gill rakers on first gill arch (vs. more than 10), from

Y. analis,Y. parvus,Y. beipanjiangensis,Y. nanpanjiangensis,andY. macrogasterby caudal-peduncle length equal or less than its depth (vs. more than its depth), and fromY. jiuchiensisby interorbital width of 36%-46% HL (vs. 20%-24%).

Yunnanilus spanisbripes An, Liu & Li, 2009

Yunnanilus spanisbripesAn, Liu & Li, 2009: 631, fig. 1 (type locality: Zhanyi County, Yunnan, China).

Yunnanilus ganheensisAn, Liu & Li, 2009: 635, fig. 11 (type locality: Ganhe, Xundian County, Yunnan, China). (new synonym)

(Figure 3Y19; Supplementary Figure S5O)

Material examined:Nine specimens, HRAS199504007,9309023, 920703001-7, 200306011, 51.2-71.9 mm SL; Deze Township, Zhanyi County, Yunnan, China, N25.9889°,E103.6064°.

Diagnosis:Whole body covered with scales; eye diameter smaller than interorbital width; processus dentiformis present;pectoral fin with 11 branched rays. One outer and 11-12 inner gill rakers on first gill arch. Body depth 16%-22% SL; lateral head length of 23%-25% SL; eye diameter 17%-22% HL;interorbital width 22%-27% HL; caudal-peduncle length 101%-139% of its depth. Caudal fin emarginate.

Description:Body elongated. Dorsal fin with 4 simple and 9 branched rays; anal fin with 3 simple and 6 branched rays;pectoral fin with 11 branched rays; pelvic fin with 7 branched rays; caudal fin with 16 branched rays. One outer and 11-12 inner gill rakers on first gill arch. Mouth inferior; upper lip smooth, lower lip thick, with strong furrows. Processus dentiformis present on upper jaw, shallow median notch on lower jaw. Anterior and posterior nostrils slightly separated,posterior nostril closer to anterior nostril than to eye, anterior nostril tube-like. Eyes medium sized, eye diameter smaller than interorbital. Lateral line incomplete, with 15-24 pores.Cephalic lateral-line canals with 7-9 supraorbital, 3+12 infraorbital, supratemporals unclear, and 6-10 mandibular pores.

Dorsal-fin origin in middle or farther from snout tip than from caudal-fin, predorsal length 51%-55% SL. Anal fin straight, tip not reaching base of caudal fin. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Caudalpeduncle depth less than its length. Caudal fin emarginate.

Whole body covered with scales. Air bladder with two chambers, anterior chamber in capsule, large posterior chamber free, filling body cavity to dorsal-fin origin. Intestines straight.

Color pattern in formalin:Back and upper part of flank brown, belly and lower part of flank yellow. Fifteen vertical,twisted, dark brown bars on flank along lateral line, space between bars three times as wide as bars. Back of body and head covered with irregular, dark brown spots. Fins hyaline.

Distribution:Known from Jinsha River basin.

Remarks:An et al. (2009) describedY. ganheensisandY.spanisbripesin the same publication, with these species distinguished from one another by size of body blotches.Additionally, more than 20 specimens ofY. spanisbripeswere collected in Huizhe County, Niulanjiang River by Y. P. Zhao(KIZ), which differed greatly in size of blotches on lateral body.Prokofiev (2010) stated that color pattern is not a reliable interspecies diagnostic character in this group of fishes, so we treatY. ganheensisas a junior synonym ofY. spanisbripesin this study.

DISCUSSION

Our results indicate that the current division of five tribes(Prokofiev, 2010) is problematic because they are not monophyletic.Micronemacheilus,Paranemachilus,

TraccatichthysandYunnanilus, four genera of the tribe Yunnanilini, are nested within the tribe Lefuini. This is consistent with the results of Chen et al. (2019b), which placedTroglonectes furcocaudalisin the genusOreonectes.Additionally,BarbatulaandHomatula, two genera of the tribe Nemacheilini, are paraphyletic with respect toTriplophysa, a genus of the tribe Triplophysini. Prokofiev (2010) placedP.brevis, the type species of the genusPetruichthys, inYunnanilus. However, we find that this species is closer to the genusSchisturathanY. jiuchiensis,which represents trueYunnanilusand forms a clade withParanemachilusandTroglonectes, indicating thatPetruichthysis not a synonym ofYunnanilus. According to Sgouros et al. (2019), the genusSchisturais polyphyletic, and Chen et al. (2019b) revealed thatP. brevisis nested within theSchisturaclade. Therefore,more morphological and molecular studies are needed to resolve the taxonomic problems ofPetruichthysandSchisturaas well as the complex relationships between these nemacheilid tribes.

In the family of Nemacheilidae, the genera ofEonemachilus,

Heminoemacheilus,Micronemacheilus,Paranemachilus,Protonemacheilus,Traccatichthys, andYunnanilusare characterized by a tube-like anterior nostril with tip not elongated to barbel-like structure and lateral line and cephalic lateral-line pores present or absent. These genera can be easily diagnosed by the relative position of anterior and posterior nostrils, lips with papillae or furrows, and cheeks scaled or scaleless. The anterior and posterior nostrils are closely set inHeminoemacheilus,Paranemachilus,

Protonemacheilus, andTraccatichthys, but slightly separated(distance greater than 1/5 of eye diameter) inEonemachilus,MicronemacheilusandYunnanilus. Furthermore, the cheeks ofParanemachilusare covered with scales (vs. scaleless in other genera).MicronemacheilusandTraccatichthysshare lips with large papillae but can be distinguished from each other by closely set anterior and posterior nostrils in

Traccatichthys(vs. clearly separated inMicronemacheilus).Our phylogenetic analysis did not groupM. pulcher(Traccatichthyspulcherin Figure 1) together withMicronemacheilusclade. Thus, we referM. pulcherandM.zispitoTraccatichthysbased on molecular evidence and their closely set anterior and posterior nostrils.

The currently recognizedYunnanilusgenus is not monophyletic (Figure 1). Freyhof & Serov (2001) treated the type species ofMicronemacheilusas a member ofYunnanilusbased on examination of type material. However, the large papillae in the median part of both lips are a useful diagnostic character to distinguishMicronemacheilusfromYunnanilus.Hence, we agree with Kottelat (2012, 2013) in terms of the inclusion ofNemacheilus cruciatusinMicronemacheilusbased on several morphological characters, i.e., anterior and posterior nostrils slightly separated and large papillae in median part of both lips.

To date, 269 species of Nemacheilidae have been recorded from China, with 161 species recorded from the karst region of southern China, including Guangxi, Guizhou, Chongqing and Yunnan. Most species of nemacheilid loaches are limited to small water bodies and are very vulnerable to changes in their environment (Kottelat & Chu, 1988; Kottelat, 2012; Yang,1991). Agricultural siltation, organic pollution, pesticides,heavy metals, habitat degradation, and severe drought have profoundly affected these endemic species (Du et al., 2017;Shu et al., 2013). Currently, four species ofYunnanilus, three species ofEonemachilus, two species ofTraccatichthys, and one species ofMicronemacheilusandParanemachilus,respectively are listed on the IUCN Red List of Threatened Species (http://www.iucnredlist.org) (IUCN, 2018). Among these species,Y. discolorisis Critically Endangered (CR),E.nigromaculatusis Endangered (EN),E. nigerandY.pleurotaeniaare Vulnerable (VU),E. pachycephalus,M.cruciatus,T. pulcherandT. taeniatuswere Least Concern(LC), andP. genilepis,Y. macrogasterandY. parvusare Data Deficient (DD). As species of Yunnanilini are valuable and rare, it is difficult to acquire fresh tissue. Hence, research regarding the phylogenetic relationships among Yunnanilini species remains limited due to a lack of appropriate tissue material.

SUPPLEMENTARY DATA

Supplementary data to this article can be found online.

COMPETING INTERESTS

The authors declare that they have no competing interests.

AUTHORS’ CONTRIBUTIONS

L.N.D. measured specimens, analyzed data, and prepared the manuscript. J.Y. collected specimens. R.M. examined specimens in KIZ. X.Y.C. and J.X.Y. contributed to funding of research and organization of the manuscript. All authors read and approved the final version of the manuscript.

ACKNOWLEDGEMENTS

We are grateful to G.H. Yu, Guangxi Normal University for conducting molecular analysis. We thank W.W. Li, S.W. Liu,Y.P. Zhao and X.L. Fan, Kunming Institute of Zoology,Chinese Academy of Sciences, and S.Z. Jiang and X.Y. Liang,Guangxi Normal University, for their generous help. We greatly thank J.H. Lan for collecting topotypical specimens ofH. bailianensis,H. zhengbaoshani,P. pingguoensis, andP.genilepis. We thank C. Watts for English corrections and suggestions.