Contracaecum nematode parasites in hillstream loaches of the Western Ghats, India.

Nematode parasites of the family Anisakidae infect definitive hosts, such as fish-eating birds and mammals, through primary intermediate hosts like copepods and secondary intermediate hosts like fishes. However, consumption of raw or undercooked fish can lead to nematode infection called anisakidosis in humans. We observed the presence of nematode infection in hillstream loaches of families Cobitidae and Nemacheilidae available for human consumption in the local markets in the northern parts of Western Ghats, India. Scanning electron micrograph and genetic identification employing mitochondrial cytochrome oxidase subunit II, identified the nematode to the genus Contracaecum. Histology of infected host revealed the presence of the parasite in muscles. Antioxidant enzyme analysis of host liver suggested that infection leads to oxidative stress in the fish. We suspect that a gradual increase in parasite infection of the loaches in the last decade could be attributed to various anthropogenic stressors that are altering riverine habitats. Since loaches are consumed by tribal people who often prepare the fish without degutting and possibly undercooked, there is a potential threat of human infection.

Triplophysa ferganaensis, a new loach species from Fergana Valley in Central Asia (Teleostei: Nemacheilidae).

Triplophysa ferganaensis sp. nov. is described from the Shakhimardan stream, a small tributary of the Syr Darya, which does not reach the river in Fergana Valley. It can be distinguished from other valid Triplophysa loaches based on the following combination of characters: body smooth and scaleless, lateral line complete, posterior chamber of air bladder degenerated, inner gill rakers 10-11 on the first-gill arch, outer gill rakers absent, vertebrae 4 + 35-36, 8 + 8 branched caudal-fin rays, caudal peduncle depth 2.1-2.7 times its length, two supratemporal pores, dorsal-fin origin closer to the caudal-fin base than to the snout tip, caudal fin emarginated and pelvic-fin tip reaching the anus. The new species can also be distinguished from its congeners based on the molecular analyses of mitochondrial cytochrome oxidase subunit I (coI) gene sequences. The phylogenetic position of this new species indicates that it is a sister taxon of Triplophysa tenuis.

A new cave-dwelling loach, Triplophysa xichouensis sp. nov. (Teleostei Nemacheilidae) from Yunnan, China.

A new cave-dwelling loach of the genus Triplophysa, T. xichouensis, is described from an outlet of a subterranean river in Xisa Town, Xichou County, Yunnan Province, China. It can be distinguished from its congeners by the following characters: dorsal-fin rays iii, 8; anal-fin rays ii, 6; pectoral-fin rays i, 9 or 10; pelvic-fin rays i, 5 or 6; branched caudal-fin rays 16(8+8); eyes highly degenerated to a very tiny black dot; dorsal-fin origin closer to snout tip than to caudal-fin base and anterior to vertical line of pelvic-fin origin; pectoral fin length about two-thirds the distance between pectoral-fin origin to pelvic-fin origin; caudal peduncle slender, its length about three times its depth; caudal fin emarginate; body smooth and scaleless; lateral line complete and straight; anterior chamber of air bladder wrapped in dumbbell-shaped bony capsule and the posterior one well developed, long, oval; intestine short, bending in zigzag shape behind stomach. A key for the cave-dwelling species of Triplophysa is provided. urn:lsid:zoobank.org:pub:9162FFB1-7911-47C3-AE50-6A00E9590327.

The complete mitochondrial genome of Triplophysa nanpanjiangensis Zhu and Cao 1988 (Cypriniformes: Nemacheilidae).

The genus Triplophysa is an ideal taxon for understanding geological evolution. In this study, for the first time, we report the complete mitochondrial genome of T. nanpanjiangensis Zhu and Cao 1988 using the Nanopore sequencing. It is a circular genome with a length of 16558 bp, comprising 22 tRNAs, 13 protein-coding genes (PCGs), two rRNAs, and one non-coding control region. The phylogenetic tree demonstrates that T. nanpanjiangensis is sister to Triplophysa zhenfengensis and placed within the genus Triplophysa. Our mitogenomic studies provide a new pathway for understanding the molecular phylogeny of the genus Triplophysa.

The complete mitochondrial genome of the freshwater fish Traccatichthys pulcher (Cypriniformes: Nemacheilidae) from China.

This study aimed to sequence and annotate the complete mitochondrial DNA genome sequence of Traccatichthys pulcher. The mitochondrial genome comprised 16,583 bp, harboring 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. The whole genome contained T (25.8%), C (26.9%), A (31.4%), and G (15.9%), showing an obvious AT bias (57.2%). Based on the concatenated protein sequences of 13 PCGs, a phylogenetic tree was reconstructed by the maximum likelihood method, and the topology revealed the monophyly of Traccatichthys, and the gathering of T. pulcher and M. pulcher. The mitochondrial DNA of T. pulcher (MZ853162.1) and M. pulcher (NC_031581.1) were aligned by the BLAST 2 sequences tool, which showed 97% similarity.

Yunnanilus chuanheensis, a new loach species (Cypriniformes: Nemacheilidae) from the upper Lixianjiang River in Yunnan, China.

A new loach species (Cypriniformes: Nemacheilidae: Yunnanilini), Yunnanilus chuanheensis sp. nov., was caught from Chuanhe in the upper reaches of the Lixianjiang River, a tributary of the Red River in Nanjian County, Yunnan Province, China. This species is a member of the traditional Y. pleurotaenia species group based on the presence of a lateral line and cephalic lateral-line canals. It can be distinguished from other species in the Y. pleurotaenia species group by the following characters: lips without papillae, anterior and posterior nostrils separated, whole body scaled, eye diameter smaller than interorbital width, outer gill raker absent on first gill arch, eye diameter greater than 18% of head length, 10-11 inner gill rakers on first gill arch, and lateral line not extending to vertical through dorsal fin insertion. To the best of our knowledge, this is the first Yunnanilus species recorded from the Red River drainage.

The mitogenome of freshwater loach Homatula laxiclathra (Teleostei: Nemacheilidae) with phylogenetic analysis of Nemacheilidae.

The complete mitogenome can provide valuable genetic information to reconstruct relationships between species. In this study, we sequenced a stone loach, Homatula laxiclathra (Teleostei: Nemacheilidae), which is found in the northern region of the Qinling Mountains in China. The size of the H. laxiclathra mitogenome is 16,570 bp, which contains 37 typical mitochondrial genes including 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and a control region (D-loop) with a total AT content of 55.8%. This is similar to other Nemacheilidae sequences published in GenBank. Furthermore, a mito-phylogenomic analysis of 46 Nemacheilidae species places H. laxiclathra in a robust monophyletic Homatula cluster with other Homatula species. Our results contribute toward a better understanding of a true phylogeny of these species based on large-scale taxonomic samplings as well as to help grasp the evolution of fish mitogenomes.

Two new species of loaches from the Irrawaddy River basin, Chin State, Myanmar (Teleostei: Cypriniformes: Nemacheilidae).

Schistura falamensis, a new species of nemacheilid loach, is described from the main channel of the Manipur River in the Irrawaddy River basin, Chin State, western Myanmar. It differs from other congeners of the genus Schistura by a combination of the following characters: 5-8 vertical bars on body; indistinct bars in front of dorsal-fin origin; bars on posterior part of body regular, twice as wide as interspace; black caudal basal bar dissociated, short, not reaching ventral extremity; males with suborbital flap; lateral line complete; and processus dentiformis weak. Schistura altuscauda is a new species described from the Htin stream, Mindat Town, Chin State, Myanmar. It can be distinguished from other congeners by a combination of the following characters: high caudal peduncle (14.0-20.3% SL), strong processus dentiformis on upper jaw; 7-19 bars on flank of body, bars in front of dorsal fin obviously thinner than those behind, sometimes fused in front of dorsal fin; lateral line complete; males with prominent suborbital flap; and pelvic lobe present.

Triplophysa sanduensis, a new loach species of nemacheilid (Teleostei: Cypriniformes) from South China.

A new species of Nemacheilidae, Triplophysa sanduensis sp. nov., is described here based on specimens collected from a small cave in Dengguang Village, Zhonghe Town, Sandu County, Guizhou Province, China. The new species can be distinguished from its congeners by the following combination of characters: branched dorsal-fin rays 8-9; branched pectoral-fin rays 8-9; branched pelvic-fin rays 5; branched anal-fin rays 5; vertebrae 4+37; snout length 45.5-50.1% of head length; postdorsal length 39.0-42.8% of standard length; caudal-peduncle depth/caudal-peduncle length range from 56.4% to 71.9%; the posterior chamber of the gas bladder degenerated; body elongated, covered by scattered scales; eyes present and normal in size, not reduced or absent; and a complete lateral line. A phylogenetic analysis based on the mitochondrial cytochrome oxidase subunit 1 (COI) gene resolved Triplophysa sanduensis as sister to Triplophysa longliensis. Kimura's 2-parameter genetic distance of the COI gene sequences between these two species was 1.9%.

The complete mitochondrial genome of Barbatula nuda and B. toni (Teleostei: Nemacheilidae).

In this study, we cloned and sequenced the complete mitochondrial genome of Barbatula nuda and Barbatula toni with 16,620 and 16,619 nucleotides, respectively. The complete mitogenomes of the two species both include 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes, and a non-coding control region. All PCGs of the two species are initiated with ATG or GTG (only for COI) and ended with complete (TAA and TAG) or incomplete (TA and T) stop codons. The complete mitochondrial genomes would provide important molecular data for further phylogenetic analyses.

Exploring taxonomic diversity and biogeography of the family Nemacheilinae (Cypriniformes).

Nemacheilidae, in the superfamily Cobitoidea, is comprised of many of morphologically similar fish species that occur in Eurasian water bodies. This large group shows inconsistencies between traditional morphological taxonomy and molecular phylogenetic data. We used mitochondrial genomes, recombinase-activating gene proteins 1 (RAG1) and the mitochondrial cytochrome c oxidase I gene (COI) to study the phylogenetic relationships among Nemacheilidae species using Bayesian inference and maximum likelihood approaches. Phylogenetic analyses based on mitogenomes provided support for two clades (I and II). The mitogenomes, RAG1, and COI results indicated that several species and genera were not consistent with the traditional morphological subdivisions. The two clades inferred from mitogenomes showed clear geographical patterns. The Tibetan Plateau, Hengduan Mountains, and the Iran Plateau may act as a barrier dividing the clades. The estimated timing of clades separation (36.05 million years ago) coincides with the first uplift of the Tibetan Plateau. We conclude that the geological history of the Tibetan Plateau played a role in the diversification and distribution of the Nemacheilidae taxa. These results provided a phylogenetic framework for future studies of this complex group.

A new Schistura from the Salween basin in western Yunnan (Teleostei: Nemacheilidae).

River loaches of the genus Schistura McClelland 1838 are small, elongated, benthic fishes of the family Nemacheilidae. Species in the genus are part of a subsistence fishery in several Southeast Asian countries due to their tasty flesh and relative abundance in suitable habitats. Fluvial environments with gravelly bottoms in tropical and subtropical regions can be co-inhabited by several species of nemacheilid loaches. Kottelat (1990) reported up to six different species coexisting in Indochinese streams in some instances. With about 200 valid taxa, Schistura is the most diverse genus within the family Nemacheilidae (Kottelat 2012). Species allocated within this genus share a moderately arched mouth, a medially notched lower lip, lack lateral labial pads, possess an air bladder without a secondary chamber, and reach a maximum standard length between 19 and 120 mm (Kottelat 1990; Ou et al. 2011).

Characterization of complete mitochondrial genome of Oreonectes furcocaudalis (Cypriniformes, Balitoridae, Nemacheilidae).

Oreonectes furcocaudalis is a rare cave-dwelling loach that lives in the karst cave of Rongshui and Rong'an county, Southwestern China. In this study, the complete mitochondrial genome of O. furcocaudalis is sequenced using the Illumina Hiseq4000 platform with de novo strategy, with a circular molecule of 16,569 bp in size (GenBank accession number KX778472). It contains 13 protein-coding, 2 ribosomal RNA, 22 transfer RNA genes, and a 917 bp control region. Phylogenetic tree based on the complete mitogenome show that Oreonectes as a clade is close to the genus Lefua and Homatula.

Taxonomy of the zodiac loaches, Mesonoemacheilus triangularis, M. tambaraparniensis and M. periyarensis, endemic to the Western Ghats of India (Teleostei: Nemacheilidae).

The Nemacheilid loaches, Noemacheilus triangularis tambaraparniensis and Nemacheilus periyarensis have been widely considered to be synonyms of the zodiac loach, Mesonoemacheilus triangularis. An integrative taxonomic investigation based on topotypic material, involving molecular analysis of two mitochondrial genes (cytochrome oxidase subunit 1 and cytochrome b), multivariate morphometric analysis based on non-metric multidimensional scaling and non-parametric multivariate analysis of variance suggests that the three species are in fact distinct.

Proteocephalid tapeworms (Cestoda: Onchoproteocephalidea) of loaches (Cobitoidea): Evidence for monophyly and high endemism of parasites in the Far East.

The parasite fauna of loaches (Cypriniformes: Cobitoidea), a group of small bottom-dwelling freshwater fishes with a mostly Eurasian distribution, remains a largely unknown quantity. Here we revise the taxonomy of tapeworms of the genus Proteocephalus Weinland, 1858 (Cestoda: Proteocephalidae) that had been found in loaches from the Palaearctic Region (Central Europe, Japan and Russia [Primorsky Region]). Molecular phylogenetic analysis based on two nuclear (ssr- and lsrDNA) and two mitochondrial genes (cox1 and rrnL) revealed a monophyletic group consisting of four valid species nesting within the Proteocephalus-aggregate: (i) Proteocephalus sagittus (Grimm, 1872) from Barbatula barbatula (Europe, Russia and Tajikistan), (ii) Proteocephalus demshini n. sp. from Barbatula toni (Russian Far East - Primorsky Region), (iii) Proteocephalus midoriensis Shimazu, 1990 from Lefua echigonia (Japan) and L. costata (Russia) (new host and geographical record), and (iv) Proteocephalus misgurni n. sp. from Misgurnus anguillicaudatus (Russia; Primorsky Region). Proteocephalus sagittus and P. demshini, and P. midoriensis and P. misgurni were recovered as sister taxa, respectively. Proteocephalus sagittus and P. demshini are characterized by having proglottids that are wider than long, an elongate to pyriform cirrus-sac and the vitelline follicles that form wide lateral bands. Proteocephalus midoriensis and P. misgurni are characterized by having proglottids that are more elongate and an ovoid to almost spherical cirrus-sac and the vitelline follicles forming narrow lateral bands. Proteocephalus demshini differs from P. sagittus in the posterolateral extent of the vitelline follicles, whereas P. misgurni can be distinguished from P. midoriensis mainly by the relative size of the ovary, posterior extent of the vitelline follicles and width of the scolex. Unlike most species of the Proteocephalus-aggregate that possess an apical sucker, all species from loaches are devoid of any apical organ. The existence of two new species in loaches from the Primorsky Region of Russia indicates high endemism of fish parasites in this region. A key to the identification of recognized species from loaches is provided.

A new species of the genus Triplophysa (Cypriniformes: Nemacheilidae), Triplophysa daochengensis, from Sichuan Province, China.

Triplophysa daochengensis sp. nov. is described from the Daocheng River, a northern tributary of the Jinsha River in Sichuan Province, China. The new species can be distinguished from its congeners by the following characters: body smooth and scales absent; lateral line complete; caudal peduncle compressed, depth unchanging; head length equal to caudal-peduncle length; lower jaw shovel-shaped; dorsal-fin origin anterior to pelvic-fin origin and closer to the tip of the snout than to the caudal-fin base, last unbranched ray hard; pelvic-fin tip not reaching anus; posterior chamber of gas bladder absent; intestine of spiral type with three winding coils.

The complete mitochondrial genome of Barbatula nuda (Cypriniformes: Nemacheilidae).

In this study, we cloned and sequenced the complete mitochondrial genome of Barbatula nuda. The genome was found to be 16,619 bp in size with a mostly conserved structural organization when compared with that of other teleost fish. It contained 37 genes (13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes) and 2 main non-coding regions (the control region and the origin of the light-strand replication). All protein-coding genes are initiated with ATG except for COX 1, which begin with GTG instead. However, the termination codons of 13 protein-coding genes varied with TAA, TA, T or TAG. The complete mitochondrial genome sequence is useful for phylogenetic analysis and studies of population genetics of B. nuda.

A new species of Triplophysa Rendahl (Cypriniformes, Nemacheilidae) from Sichuan Province, China.

Triplophysa yajiangensis sp. nov. is described from the upper and middle reaches of the Yalong River, Yangtze Basin, Ganzi Prefecture, Sichuan Province, China. This new species can be distinguished from other congeneric species by the following characters: body surface smooth and scaleless; lateral line complete; caudal peduncle compressed and tapered slightly; lower jaw shovel-shaped; head shorter than caudal peduncle; dorsal-fin origin anterior to pelvic-fin origin and closer to tip of snout than to caudal-fin base, last unbranched ray hard; pelvic-fin reaches or exceeds anus; posterior chamber of gas bladder absent; intestine spiral type with 3-5 winding coils.

Schistura sexnubes, a new diminutive river loach from the upper Mekong basin, Yunnan Province, China (Teleostei: Cypriniformes: Nemacheilidae).

An ichthyofaunistic survey of Mekong tributaries in Lincang Prefecture, Yunnan Province, China yielded a new species of nemacheilid loach, herein described as Schistura sexnubes species nova. The new species is readily distinguishable from its congeners by the following combination of characters: 8+8 branched caudal fin rays, an incomplete lateral line, a dissociated caudal bar, a shallow caudal peduncle depth (7.6%-9.6% SL; respectively caudal peduncle 1.76-1.95 times longer than deep), a diminutive size of less than 50 mm SL, and no sexual dimorphism. A dorsocephalic pattern consisting of a black, forward directed V-shaped formation located between the nares, and a white, ovoid blotch on the upper operculum serves as an autapomorphy.