No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Rhyacoschistura larreci, a new genus and species of loach from Laos and redescription of R. suber (Teleostei: Nemacheilidae)
Abstract
Rhyacoschistura, new genus, belongs to a group of genera (Physoschistura, Mustura, Pteronemacheilus, Petruichthys) characterised by the modified branched pectoral-fin rays of males, with a very thick first ray, usually without membranes between some of the branches and/or rays, and anterior rays and/or membranes covered by small tubercles at maturity. Rhyacoschistura is distinguished from them by the combination of: presence of a suborbital flap; emarginate caudal fin; lower lip with a wide median interruption and connected to isthmus by a frenum; body depth about equal from behind head to caudal-fin base. Rhyacoschistura larreci, new species, is described from the Mekong drainage in Xayaburi Province, Laos. It is distinguished by details of the morphology of the pelvic fin, and its colour pattern (flank with numerous narrow slanted bars, very irregularly organised and shaped, more or less connected, or sometimes covering the whole flank). Schistura suber, from Nam Ngum watershed, is redescribed on the basis of adults and placed in Rhyacoschistura.
... The family has its greatest diversity in Southeast Asia, from where about 290 valid species are recognised (Kottelat, 2012a(Kottelat, , 2013; most species from Sundaland are described and figured in Kottelat (1984Kottelat ( , 1990a, Hadiaty & Kottelat (2009, 2010, Hadiaty & Siebert (2001), Tan & Kottelat (2009), and Hadiaty & Yamahira (2014). Additionally, new genera of Nemacheilidae are still being discovered or recognised (e.g., Kottelat, 1990aKottelat, -b, 2012aKottelat, -b, 2017Kottelat, , 2018Kottelat, , 2019Freyhof & Serov, 2001;Bohlen & Šlechtová, 2011;Kottelat & Grego, 2020;Conway & Kottelat, 2023). Roberts (1989) described Nemacheilus maculiceps , from the Kapuas drainage in Borneo. ...
... Remarks. In a number of nemacheilid genera, the presence of tubercles on the dorsal side of the anterior pectoral-fin rays of the males, the pattern of their distribution, their size etc. are diagnostic features (e.g., see Kottelat, 2018Kottelat, , 2019Conway & Kottelat, 2023). However, in males of some species their presence and development apparently vary with age, season, and sexual activity (MK, pers. ...
Kapuasia, new genus, is created to accommodate 'Nemacheilus' maculiceps, from the Kapuas drainage on Borneo. It is distinguished by the presence of a large suprapectoral flap above the pectoral fin, and its unique lip morphology. The lower lip has a continuous anterior edge, and its median part has 8-10 ridges on each side, radiating at the anterior extremity, across the whole lip, resulting in a crenulated inner edge of the lip.
... In recent years, more detailed morphological studies have resolved the relations of some groups of species within these catch-all genera (e.g. Conway and Kottelat, 2023;Dvořák et al., 2023;Kottelat, 2018;Kottelat, 2019). Moreover, every genetic study that included more than five species of Schistura resulted in polyphyly of the genus (e.g. ...
Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive, large-scale reconstructions illustrating the extent of these influences are lacking. We reconstructed the evolutionary history of the freshwater fish family Nemacheilidae across Eurasia and spanning most of the Cenozoic on the base of 471 specimens representing 279 species and 37 genera plus outgroup samples. Molecular phylogeny using six genes uncovered six major clades within the family, along with numerous unresolved taxonomic issues. Dating of cladogenetic events and ancestral range estimation traced the origin of Nemacheilidae to Indochina around 48 mya. Subsequently, one branch of Nemacheilidae colonised eastern, central, and northern Asia, as well as Europe, while another branch expanded into the Burmese region, the Indian subcontinent, the Near East, and northeast Africa. These expansions were facilitated by tectonic connections, favourable climatic conditions, and orogenic processes. Conversely, aridification emerged as the primary cause of extinction events. Our study marks the first comprehensive reconstruction of the evolution of Eurasian freshwater biodiversity on a continental scale and across deep geological time.
... The family has its greatest diversity in Southeast Asia, from where 251 valid species are presently recognised (count of 3 October 2024; Kottelat, 2012aKottelat, , 2013; most species from Sundaland are described and figured in Kottelat (1984Kottelat ( , 1990a, Hadiaty & Kottelat (2009, 2010, Hadiaty & Siebert (2001), Tan & Kottelat (2009), Hadiaty & Yamahira (2014), and Kottelat & Tan (2024). Additionally, new genera of Nemacheilidae are still being discovered or recognised (e.g., Kottelat, 1990Kottelat, , 2012aKottelat, , b, 2018Kottelat, , 2019Freyhof & Serov, 2001;Bohlen & Šlechtová, 2011;Kottelat & Grego, 2020;Kottelat & Tan, 2024). Roberts (1989) described Nemacheilus maculiceps from the Kapuas drainage in Borneo. ...
Kapuasia falaris, new species, is described from the Barito drainage on Borneo. It is distinguished from its only congener K. maculiceps in having a conspicuous colour pattern of 3-7 regular black bars on the flank, on a white background; in males, presence of a suborbital flap and vertical skin flanges on the dorsal surface of the pectoral fin between the branched rays; in males, pectoral axillary lobe cylindrical, with pointed posterior extremity, usually separate from skin of flank by a deep groove, often with a second similar lobe above the groove. The shape of this lobe is apparently unique among Southeast Asian species of nemacheilids, as well as the shape of the suborbital flap (globulous, at some distance below the eye, with a deep vertical groove from the flap to the eye). The strongly upwards curled pectoral fin, appearing with an almost vertical orientation in life, is apparently unique among Southeast Asian nemacheilids.
... obs., updated from Kottelat, 2012Kottelat, , 2013, distributed throughout Eurasia and Africa (Ethiopia). New species and even new genera are still described regularly, especially from South and Southeast Asia (e.g., Kottelat, 2017Kottelat, , 2018Kottelat, , 2019Kottelat & Grego, 2020); yet the relationships among the majority of genera remain poorly understood and many genera are known to be polyphyletic, including for example Schistura McClelland, 1838 (Kottelat, 1990;Sgouros et al., 2019;Dvořák et al., 2022Dvořák et al., , 2023 and Physoschistura Bănărescu & Nalbant in Singh, Sen, Bănărescu & Nalbant, 1982(Dvořák et al., 2022. ...
Physoschistura mango, new species, is described from Shan State, Myanmar. It is distinguished from congeners by having an extremely short and incomplete lateral-line canal on the body, with only 5-6 pores; several reductions in the cephalic lateral-line canal system; and by features of the colour pattern, including a dark black to brown horizontal stripe along body side combined with a bright orange-reddish background colour in mature males. With a maximum recorded length of 23.4 mm SL, it represents one of the smallest members of the family Nemacheilidae.
... Nemacheilidae is a family of cypriniform fishes with more than 760 known species in 49 genera that mostly inhabit fast-flowing stream environments and is widely distributed in Eurasia Kottelat 2012a, b;Kottelat 2019;Kottelat & Grego 2020;Zhao et al. 2021). In recent years, many new species within Nemacheilidae have been described, especially in Southeast Asia and China (e.g., Chen et al. 2020;Dvořák et al. 2022;Jiang et al. 2021;Kottelat 2022). ...
... obs., updated from Kottelat, 2012Kottelat, , 2013, distributed throughout Eurasia and Ethiopia. Besides, new species and genera are still regularly described (e.g. in Southeast Asia: Bohlen & Šlechtová, 2011aBohlen & Šlechtová, -b, 2013aOu et al., 2011;Bohlen et al., 2014Bohlen et al., , 2016Kottelat, 2017aKottelat, -h, 2018Kottelat, , 2019Kottelat, , 2021Kottelat, , 2022Kottelat & Grego, 2020). Among them, the genus Nemacheilus presently includes about 36 valid species, all endemic to Southeast Asia (Chao Phraya, Mae Khlong, and Mekong drainages, Malay Peninsula, Sumatra, Java and Borneo) (pers. ...
Nemacheilus pullus, new species, is described from the Nam Ngiep and Nam Xan watersheds, Mekong drainage, in central Laos. It was earlier misidentified as N. platiceps. It is distinguished from congeners in having an incomplete lateral line, with 23-57 pores, reaching between verticals of pelvic-fin origin and of anus; anterior nare at tip of a short tube; body plain yellowish grey in life in adults; a conspicuous suborbital flap in males; small tubercles on anterior pectoral-fin rays and on flank. It was found in habitats with moderate flow, usually small streams, on mud to stone bottoms. An informal platiceps group is recognised, including N. platiceps, N. cacao and N. pullus.
... Nemacheilidae is a family of cypriniform fishes with more than 760 known species in 49 genera that mostly inhabit fast-flowing stream environments and is widely distributed in Eurasia Kottelat 2012a, b;Kottelat 2019;Kottelat & Grego 2020;Zhao et al. 2021). In recent years, many new species within Nemacheilidae have been described, especially in Southeast Asia and China (e.g., Chen et al. 2020;Dvořák et al. 2022;Jiang et al. 2021;Kottelat 2022). ...
Paracanthocobitis putaoensis sp. nov. is described based on analysis of morphological and molecular data (cytochrome c oxidase subunit I-COI). The new species was collected from the Mali Hka River, a tributary of the Irrawaddy River near Putao in Kachin State in northern Myanmar. It can be easily distinguished from all other species of the genus Paracanthocobitis by an incomplete lateral line, a suborbital groove in adult males, and a well-developed axillary pelvic lobe. Phylogenetic relationships of the genus Paracanthocobitis based on the mitochondrial COI locus are revealed for the first time. Maximum likelihood and Bayesian inference phylogenetic analyses indicate that the new species forms an independent clade. Both morphological and molecular phylogenetic analyses suggest that P. putaoensis is a new species.
... obs., updated from Kottelat 2012Kottelat , 2013, distributed throughout Eurasia and Ethiopia. New species and genera are still regularly described (e.g. in Southeast Asia: Bohlen & Šlechtová 2010Bohlen & Šlechtová , 2011Bohlen & Šlechtová , 2013aOu et al. 2011;Bohlen et al. 2014Bohlen et al. , 2016Kottelat 2017aKottelat -h, 2018Kottelat , 2019Kottelat , 2021Kottelat & Grego 2020). Among them, the genus Nemacheilus presently includes about 35 valid species, all endemic to Southeast Asia (Chao Phraya, Mae Khlong, and Mekong drainages, Malay Peninsula, Sumatra, Java and Borneo) (pers. ...
Nemacheilus pezidion, new species, is described from the Xe Kong watershed, Mekong drainage, in Attapeu province, southern Laos. It is distinguished from all other Nemacheilidae in Southeast Asia by its unique colour pattern consisting of a black midlateral stripe and a middorsal row of 11-15 narrow saddles. Besides, the male has a globulous suborbital flap with tubercles along its posterior edge, and the pectoral fin with thickened anterior rays, and branched rays 1-4 and unculiferous pads behind them covered by small tubercles. It was found in habitats with moderate flow, on mud to gravel bottom. Nemacheilus pezidion was earlier misidentified as N. longistriatus.
... obs., updated from Kottelat 2012Kottelat , 2013, distributed throughout Eurasia and Ethiopia. Besides, new species and genera are still regularly described (e.g. in Southeast Asia: Bohlen & Šlechtová 2010Bohlen & Šlechtová , 2011Bohlen & Šlechtová , 2013aOu et al. 2011;Bohlen et al. 2014Bohlen et al. , 2016Kottelat 2017aKottelat -h, 2018Kottelat , 2019Kottelat & Grego 2020). Among them, the genus Nemacheilus presently includes about 29 valid species, all endemic to Southeast Asia (Chao Phraya, Mae Khlong, and Mekong drainages, Malay Peninsula, Sumatra, Java and Borneo) (pers. ...
‘Nemacheilus’ argyrogaster, new species, is described from the Xe Kong, Mekong drainage, in Attapeu and Xe Kong provinces, southern Laos. It is distinguished from all other Nemacheilidae in Southeast Asia by its unique colour pattern made of a bold black midlateral stripe separating the yellowish brown dorsal part of the body from the silvery whitish ventral part and a middorsal row of 14–19 thin saddles. Besides, the male has a globulous suborbital flap with tubercles along its free, posterior edge, and the pectoral fin with thickened anterior ray and branched rays 1–4 and unculiferous pads behind them covered by small tubercles; lips thin, lower lip continuous with a narrow median notch. It was found in moderate to fast flowing water, over pebble to stone bottom. ‘Nemacheilus’ argyrogaster, was earlier misidentified as N. longistriatus; it is provisionally placed in the genus Nemacheilus.
Koima, a new genus of nemacheilid loach, is described for Mesonoemacheilus remadevii Shaji 2002, and Nemacheilus monilis Hora 1921, both of which are endemic to the Western Ghats of southern peninsular India. Koima is distinguished from all other genera of family Nemacheilidae by its unique colour pattern comprising a yellowish-brown ground colour, single row of black spots on lateral line, all fins hyaline, and absence of a uniform banding pattern on dorsal side. Koima remadevii was initially identified as a species of Mesonoemacheilus Bănărescu & Nalbant 1982, from which it can be distinguished by the presence of a lower adipose crest, and an absence of a banding pattern on the dorsal side and on the caudal fin, while Koima monilis was initially identified as a species of Nemacheilus Bleeker 1863, from which it can be distinguished by the presence of a lower adipose crest, a narrow and deeply incised upper lip and having the fins hyaline. In the multi-gene phylogenetic analysis based on concatenated mitochondrial and nuclear gene sequences, Koima remadevii and K. monilis were recovered in a monophyletic group, sister to the endemic peninsular Indian nemacheilid, Schistura denisoni. Resolution of the identity of Koima remadevii and K. monilis contributes to our understanding of the phylogenetics of family Nemacheilidae, which is widely considered to be a polyphyletic group.
Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic era, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive, large-scale reconstructions illustrating the extent of these influences are lacking. We reconstructed the evolutionary history of the freshwater fish family Nemacheilidae across Eurasia and spanning most of the Cenozoic era. Molecular phylogeny uncovered six major clades within the family, along with numerous unresolved taxonomic issues. Dating of cladogenetic events and ancestral range estimation traced the origin of Nemacheilidae to Indochina around 48 million years ago. Subsequently, one branch of Nemacheilidae colonised eastern, central, and northern Asia, as well as Europe, while another branch expanded into the Burmese region, the Indian subcontinent, the Near East, and northeast Africa. These expansions were facilitated by tectonic connections, favourable climatic conditions, and orogenic processes. Conversely, aridification emerged as the primary cause of extinction events. Our study marks the first comprehensive reconstruction of the evolution of Eurasian freshwater biodiversity on a continental scale and across deep geological time.
Due to the growing need for freshwater resources, water diversion projects are becoming an essential part of international water management plans. While hydropower is considered renewable, its environmental impact includes altered river flows, disrupted fish migration, and sediment retention affecting ecosystems. Water diversion projects impact aquatic flora and fauna and their habitats. Sustainable water management is crucial, considering the potential effects such as variations in temperature, sediment movement, and flow patterns caused by dam construction. In aquatic habitats building hydropower projects reduced connectivity, altered nutrient dynamics, and habitat fragmentation can decrease organism diversity and numbers, posing a significant threat to biodiversity in affected areas. A comprehensive approach that includes adaptive management and environmental impact evaluations is crucial for water diversion projects, as this abstract highlights. Addressing water diversion impacts on biodiversity is essential for long-term environmental sustainability.
Over the last few decades, considerable concern has been expressed about the threat of Mekong River Basin hydropower dams to a range of important freshwater riverine fisheries, particularly for fish that seasonally migrate long distances. However, much less attention has been given to the threat of hydropower dams to fish biodiversity in the high-diversity Mekong River Basin, the focus of this paper. Through reviewing the existing state of knowledge regarding Mekong River Basin fish biodiversity, and threats to it, we argue that even though no species are definitively known to have been extirpated from the Mekong River Basin to date, hydropower dam development and various other developments nevertheless pose a serious threat to fish biodiversity. Indeed, dams typically significantly block fish migrations and fish larvae distribution, cause river fragmentation, fundamentally alter river hydrology, and change water quality, all factors that have the potential to intersect with each other and lead to significant species extirpation and extinction, or in some cases, functional extinction, when a small population remains but the important larger population is lost permanently. The circumstances are further exacerbated by the lag time between impact and when that impact becomes evident, cumulative impacts, a lack of consistent data collection, including the collection of base-line data, and insufficient post-project research related to biodiversity. We contend that much more could and should be done to ensure that the Mekong River basin’s exceptional fish biodiversity is not variously diminished and destroyed during the coming years.
Simple Summary
Since large animal families with unresolved taxonomy are difficult to study, it is better to focus on smaller units. In the present study, we test if we can define a restricted group of species within a large and unsorted fish family (Nemacheilidae). In the beginning, we selected 17 candidate species that share a rare and specific pigmentation pattern, and 29 comparative species with a different pattern. We studied their relationships and the ages of pedigree branches using molecular genetic markers. It turned out that the candidate and comparative species are intermixed in two main groups, meaning that the specific pigmentation pattern is not diagnostic. However, the genetic lineages themselves are smaller units within the large family Nemacheilidae and can be used for further studies. For example, one group revealed its evolutionary history: it expanded 12 million years ago from India into Myanmar and later further to Thailand, Laos, and China. They also revealed more than 20% of undescribed species, a very high rate in vertebrates. Our results show that species groups can be a helpful tool to approach large and unsorted animal units. This finding offers species groups as a new tool for future studies exploring the diversity of life on earth.
Abstract
Large animal families with unresolved taxonomy are notoriously difficult to handle with respect to their biodiversity, systematics, and evolutionary history. We approach a large and taxonomically unresolved family of freshwater fishes (Nemacheilidae, >600 species) by proposing, on the basis of morphologic data, a species group within the family and study its phylogeny with conclusions regarding its diversity, taxonomy, and biogeographic history. Phylogenetic analyses of two mitochondrial and three nuclear genes of 139 specimens, representing about 46 species (17 candidate species from the proposed species-group, plus 29 comparative species), revealed that the proposed species group does not form a distinct monophyletic lineage, but that the candidate and comparative species mixed in three different lineages. However, the results revealed more than 20% of undescribed species within the ingroup and showed that species do not cluster according to the presently recognised genera. At least one of the genetic clades shows signs of an eastward range expansion during the second half of Miocene from north India via Myanmar into Laos, western China, and western Thailand. We conclude that the approach of picking monophyletic lineages to study biodiversity, systematics, and evolutionary history helps to open the door to large animal families.
Kayahschistura lokalayensis, new genus and species, is described from Lokalay Loku Gu Cave, Kayah State, Myanmar. It is related with species of the genera Mustura, Pteronemacheilus, Physoschistura, Petruichthys and Rhyacoschistura, but cannot be placed in any of the presently named genera. It is distinguished by the absence of colour pattern, the eye very regressed and at the bottom of a longitudinal slit, the presence of a suborbital flap, the forked caudal fin, the presence of a large posterior chamber of the air bladder in the abdominal cavity, and the modified pectoral-fin rays, especially the presence of numerous small tubercles on the dorsal surface of branched rays 1-3 and membranes between them.
Schistura thavonei, new species, is described from the Nam Ma, Mekong drainage, in Louang Namtha Province, northwestern Laos. It is distinguished from all other Nemacheilidae by its unique colour pattern made of two broad dark brown stripes (one middorsal, one midlateral) and between them a pale yellowish-brown stripe (iridescent in life); a row of 12–24 short black bars are located increasingly lower on the flank from head to tail, posterior-most ones restricted to the lower half of the body or forming blotches along the ventral midline of the caudal peduncle. Besides, it has an elongate body with a hump immediately behind the head, 8+7 branched caudal-fin rays; and 9–10 total pectoral-fin rays. It was found in riffles, over gravel to stone bottom.
Schistura colossa, new species, is described from the Xe Pian, Xe Set and Houay Champi on Bolaven Plateau in southern Laos. It is distinguished by its large size (up to at least 98 mm SL); the body has 16–21 bars, quite regularly shaped in juveniles and with increasing size becoming more irregular; in the largest individuals the bars on the caudal peduncle are broken up in irregular blotches. Schistura klydonion, new species, is described from the Xe Namnoy, also on Bolaven Plateau. It is distinguished by its relatively large size (up to at least 76 mm SL); the body has a midlateral row of 12–21 bars that do not reach the dorsal midline and that alternate with a middorsal row of saddles or small blotches, leaving a pale zigzag line between the two rows; the lips have a few sparsely-set pointed papillae. The topography of the plateau and the distribution of the endemic species suggest an earlier connection of the Houay Makchang Gnai and the Xe Katam with the Xe Pian instead of the Xe Namnoy. Both species are endemic to the Bolaven Plateau, have a limited distribution and are impacted by hydropower and agricultural activities.
Malihkaia aligera, new genus, new species, is described from the Mali Hka River in the northernmost Kachin State, Myanmar. It is distinguished by strongly furrowed lips and a type of sexual dimorphism new in Nemacheilidae: the pectoral fin of males is greatly elongated as a ‘wing’, rigid and curled, with the first branched ray the longest, and with all branches and sub-branches adjacent and without membranes between them. Schistura nubigena, new species, is described from the same locality. It is distinguished by its colour pattern that evolves from 4 broad bars in juveniles about 20 mm SL, to a pattern of 8 bars that become coalescent along the flank and along the back, leaving a row of pale spots between them. Schistura wanlainensis, new species, is described from the Mon Lan Chaung, a tributary of the Mali Hka. It is distinguished by its unique colour pattern of a pale grey to whitish background with 18–32 narrow, regularly shaped black bars, extending from dorsal midline and reaching downwards to below level of pectoral fins, continuous over back with contralaterals, wider than interspaces anteriorly, narrower than interspaces on caudal peduncle; some of anterior bars fused at their dorsal extremity.
Schistura kampucheensis, new species, is described from several localities in Cambodia. It is distinguished from all other species of Schistura by a combination of the following characters: 6-11 more or less regular, continuous black bars on body, reaching ventrally usually to level of pectoral fins; no black midlateral stripe; 8 1 /2 branched dorsal-fin rays; 8 + 8 branched caudal-fin rays; 7 pelvic-fin rays; anus situated 1.7-2.5 eye diameters before anal-fin origin; males without suborbital flap; axillary pelvic lobe present. Schistura kampucheensis had earlier been mis-identified as S. pellegrini.
Schistura ferruginea, new species, is described from a small rivulet of the Barak River drainage (Brahmaputra basin) at Maram, Senapati district, Manipur, India. It is distinguished from congeners by a unique combination of characters: no axillary pelvic lobe, a patch of dusky pigment deep under the skin at mid-lateral line above pectoral fin, 17-19 thin irregular dark olivaceous bars on body, 7 1/2 branched dorsal-fin rays, incomplete lateral line, and truncated to slightly emarginate caudal fin with 9 + 8 branched rays.
Schistura shuensis, new species, is described from Shu stream on the eastern slope of the Rakhine range in Myanmar. It reaches up to 39.1 mm SL and is diagnosed by a combination of the following characters: males with suborbital flap, bearing tubercles on its posterior part, females with suborbital groove; caudal fin deeply forked (mean length of median caudal-fin rays 57 % of length of upper caudal lobe); caudal peduncle shallow (depth 11-12 % SL and 49-63 % of body depth); and presence of 6-9 indistinct dark brown bars on body.
Schistura hypsiura, a new species, is described from the western slope of the Rakhine Yoma, Myanmar. It is distinguished from all congeners by having a very deep caudal peduncle without dorsal and ventral skin crests, a deeply forked caudal fi n, a suborbital fl ap in adult males, and a well-developed suborbital groove in adult females.
Schistura rubrimaculata, new species, is described from two streams on the eastern slope of the Rakhine Range draining in Irrawaddy River. It reaches up to 27.7 mm SL and differs from all other species of Schistura by the presence of a distinct red dot above the midlateral line before the caudal-fin base (not visible in preserved specimens), a very slender body and a white ventral side below a broad black midlateral stripe; the dorsal side of the snout dark grey, and the anus located close to the anal-fin origin. Schistura pawensis, new species, shares with S. rubrimaculata the small size, slender body and general pigmentation pattern and is considered as closely related to S. rubrimaculata. Schistura pawensis differs from S. rubrimaculata in having fewer branched rays in caudal and dorsal fins, the anus at mid-distance between pelvic and anal fins, fewer pores in lateral line, the dorsal side of the snout white, and the red dot on the caudal peduncle smaller and less prominent.
There are 3108 valid and named native fish species in the inland waters of
Southeast Asia between the Irrawaddy and Red River drainages, the small coastal drainages
between the Red River and Hainan, the whole Indochinese Peninsula, Andaman and Nicobar
Islands, Indonesia (excluding Papua Province, Waigeo, Aru [but Kai is included]), and the
Philippines. They belong to 137 families. Their taxonomy and nomenclature are reviewed. The
original descriptions of all 7047 recorded species-group names and 1980 genus-group names
have been checked in the original works for correct spelling, types, type locality and bibliographic references. The bibliography includes about 4700 titles. Synonymies are given, based on published information as well as unpublished observations.
The names of 49 introduced species and 347 extralimital taxa cited in the discussions have
also been checked. The original descriptions of all species not present in the covered area but
cited as type species of genera have been checked for availability, authorship, date and correct
spelling. The availability of some family-group names has been checked when there was suspicion of possible nomenclatural problems.
Bibliographic notes include new informations on the dates of publication of works by, among
others, Bleeker, Bloch, Heckel and Steindachner and discussion of authorship of names in various works.
Schistura udomritthiruji, new species, is described from streams draining to the Andaman Sea in southern Thailand between Takua Pa and Ranong. It is distinguished from congeners by the following characters: dark bars on the body much thinner in the anterior half of the body than in the posterior half; 9+8 branched rays in the caudal fin; males with suborbital flap; lateral line ends above base of anal fin; caudal fin hyaline and dark bars on posterior half of body more than twice as wide as interspaces.
A new genus (Laocypris) and 64 new species of fishes are described from Laos. The new species belong to the genera Acrossocheilus (1), Crossocheilus (1), Danio (3), Garra (1), Laocypris (1), Mystacoleucus (1), Poropuntius (4), Puntius (1), Rasbora (2) (Cyprinidae), Hemimyzon (2), Homaloptera (1), Schistura (39), Sectoria (1), Vanmanenia (2) (Balitoridae), Pseudomystus (1) (Bagridae), Doryichthys (1) (Syngn ath id ae), C hauduria (1) (C hau d h u riid ae) and M onotrete (1) (Tetraodontidae). Introduction Fish surveys conducted in Laos between 1996 and 1999 have increased the number of species known in the country from some 210 recorded in the literature as at 1996 to 481 (15 of them not native to the country) recognized in a just-completed field guide (Kottelat, 2000a). Several of the species discovered during these surveys have been described elsewhere (e.g., Britz & Kottelat, 1999a, b; Chen et al., 1999; Chen & Kottelat, 2000; Fang & Kottelat, 1999,2000; Kottelat, 1998; Kottelat & Brehier, 1999; Kottelat & Ng, 1999; Larson & Vidthayanon, 2000; Ng, 1999a-b; Ng & Kottelat, 1998, 1999,2000a-c). The field guide is due to be published in the second quarter of 2000 (a time-frame beyond my control) and clearly, it is desirable that the large number of species still unnamed should be named and identified in this work. It would be counterproductive to omit them from the fieldguide or to list them without valid names. The purpose of the present paper is to make names formally available for them.
Schistura diminuta, new species, is described from the lower Sekong River, Mekong drainage, Cambodia. It is distinguished from congeners by the following characters: tiny adult body size (maximum known size 19.5 mm SL); lateral line incomplete, with 14-17 pores, terminating on the flank anterior to vertical through pelvic-fin origin; absence of axillary pelvic lobe; processus dentiformis weakly developed; dorsal-fin rays iii-iv.8.i; principal caudal-fin rays 8 + 8 (7 + 7 branched caudal-fin rays); a distinct dark brown spot at centre of caudal-fin base; and 9-10 irregular light brown bars along dorsal body surface.
Schistura porocephala, a new nemacheilid species, is described from a stream that drains into the Mat River (Koladyne basin), India. It is characterized by the presence of prominent pores in the cephalic lateral line system; an incomplete lateral line; 20–23 thin dark olivaceous bars on the body, often bifurcated from the dorsolateral region; a depressed head and body anterior to the dorsal fin origin; and an elongated suborbital flap arising in front of the nostril and extending to the anterior one-third of the eye diameter in males.
Schistura maculosa, a new species of loach, is described from Tuingo and Pharsih Rivers, tributaries of Tuivai River (Barak drainage) in Mizoram, northeastern India. It is distinguished from other closely related Schistura species in having an axillary pelvic lobe; an incomplete lateral line; 20–30 narrow black bars on the body; 3–4 rows of black spots horizontally across the dorsal-fin; a slightly emarginate caudal-fin, with 5–7 rows of black spots more or less regularly arranged vertically on rays across the fin, and 8+8 branched caudal-fin rays.
Mustura celata, new genus and species, is described from small tributaries of Lake Indawgyi, Myanmar. Mustura is distinguished from other genera of Nemacheilidae by having: the male pectoral fin slanted upwards, with branched ray 1 wider than following rays, branched once and branches close together, without membrane between them except near tip; wide, thickened unculiferous pad extending along anterior branched pectoral-fin rays, covered dorsally by small conical tubercles; two air bladder capsules connected by a manubrium and posterior chamber small and circular, or absent; lower lip with wide median interruption, two halves forming an acute angle, not in contact medially, wide and fleshy medially, forming a triangular ‘cushion’, partly free from jaw and connected to throat by a frenum; suborbital flap present, with small tubercles on posterior extremity. Most species earlier placed in Physoschistura in fact belong to Mustura. Physoschistura is diagnosed by having the two halves of the air bladder capsule joined medially (without manubrium) and the posterior chamber free, well developed and in direct contact with the capsule; it presently includes only P. brunneana (type species), P. pseudobrunneana, and possibly P. elongata, P. raoi and P. rivulicola. Mustura celata is distinguished from the other species of Mustura by, among others, the colour pattern (6-10 [usually 7] very irregular blotches or bars on flank, alternating with irregular saddles); 9 + 8 branched caudal-fin rays; 8 ¹/2 branched dorsal-fin rays; lateral line complete; caudal peduncle depth 1.3-1.7 times in its length. Schistura shuensis, S. maepaiensis and S. bella belong to Mustura. Physoschistura absumbra belongs to Schistura s. l.; P. shuangjiangensis belongs to a distinct genus, apparently unnamed. Mustura, Pteronemacheilus, Physoschistura and Petruichthys seem to be closely related; they share features of the mouth morphology and unique features of the male pectoral fin and suborbital flap.
Schistura titan, new species, is described from the Dakchung Plateau in southern Laos. It is distinguished by the presence of a large posterior chamber of the air bladder in the abdominal cavity, 8 + 7 branched caudal-fin rays; maximum known size 95 mm SL; 17 or 18 bars on flank; the nostril flap pointed, reaching the anterior margin of the eye; and 81/2 branched dorsal-fin rays. Dakchung Plateau lies at 800-1400 m asl; only 11 fish species are known from the plateau, of which four apparently are endemic.
Schistura systomos, new species, is described from the Bolaven Plateau in southern Laos. It is distinguished by having a very small mouth, possibly the smallest in the family. The mouth occupies only the median half of head width. The head is about circular in cross-section, its lower surface is flat only in middle, and the infraorbital area is not expanded laterally. The snout is blunt. The interorbital area, is deep and rounded, and the eyes are partly or almost visible in ventral view. Compared to other nemacheilids, the stomach is smaller and the intestine very thin. A dissected female 34.5 mm SL had an ovary with 14 large yellow ova, 1.2-1.4 mm diameter. It was found among blocks and stones downstream of a waterfall.
Schistura indawgyiana, new species, is described from a hill stream, tributary of Lake Indawgyi, Myanmar. It is distinguished from other species of Schistura in Southeast Asia by having an irregular blackish midlateral stripe
made of a row of closely-set, vertically elongated blotches; the absence of a regular saddle pattern on the back;
a small oval black blotch at the middle of the base of the caudal fin; a reduced number of branched rays in pectoral (8-9), pelvic (7) and caudal fins (7 + 7); and an incomplete lateral line ending before the origin of the pelvic fin.
Schistura epixenos, new species, is described from the Nakai Plateau in Laos. It is distinguished from its congeners in Southeast Asia with a pattern of dark brown bars on a pale brown background by a combination of characters including, among others, a slender body, body with 13–17 bars reaching downwards to the level of the pectoral fin, a complete lateral line, scales present in the predorsal area, and the pelvic-fin origin below the dorsal-fin origin.
Acanthocobitis pictilis, new species, is described from the Ataran drainage in Myanmar and the Mae Khlong drainage in Thailand. It had earlier been misidentified as A. rubidipinnis. It is distinguished by, among other characters, its colour pattern, especially the dark brown triangular saddles in the upper half of the body, strongly slanted anteriorly and becoming almost vertical posteriorly, becoming paler in the middle, and forming pairs of narrow saddles in large individuals; lateral line complete; 12 1/2 or 13 1/2 branched dorsal-fin rays. Acanthocobitis mandalayensis is a valid species, removed from the synonymy of A. botia.
An heuristic checklist of the freshwater fishes of Europe (exclusive of former USSR), with an introduction for non-systematists
and comments on nomenclature and conservation
Members of the teleost superorder Ostariophysi dominate freshwater habitats on all continents except Antarctica and Australia. Obligate benthic and rheophilic taxa from four different orders of the Ostariophysi (Gonorynchiformes, Cypriniformes, Characiformes, and Siluriformes) frequently exhibit thickened pads of skin along the ventral surface of the anteriormost ray or rays of horizontally orientated paired (pectoral and pelvic) fins. Such paired-fin pads, though convergent, are externally homogenous across ostariophysan groups (particularly nonsiluriform taxa) and have been considered previously to be the result of epidermal modification. Histological examination of the pectoral and/or pelvic fins of 44 species of ostariophysans (including members of the Gonorynchiforms, Cypriniformes, Characiformes, and Siluriformes) revealed a tremendous and previously unrecognized diversity in the cellular arrangement of the skin layers (epidermis and subdermis) contributing to the paired-fin pads. Three types of paired-fin pads (Types 1-3) are identified in nonsiluriform ostariophysan fishes, based on differences in the cellular arrangement of the epidermis and subdermis. The paired-fin pads of siluriforms may or may not exhibit a deep series of ridges and grooves across the surface. Two distinct patterns of unculus producing cells are identified in the epidermis of the paired-fin pads of siluriforms, one of which is characterized by distinct bands of keratinization throughout the epidermis and is described in Amphilius platychir (Amphiliidae) for the first time. General histological comparisons between the paired fins of benthic and rheophilic ostariophysan and nonostariophysan percomorph fishes are provided, and the possible function(s) of the paired-fin pads of ostariophysan fish are discussed. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.
Fish and fisheries of Manipur with some observations on those of the Naga hills
- S L Hora
Hora, S.L. (1921) Fish and fisheries of Manipur with some observations on those of the Naga hills. Records of the indian Museum, 22, 165-214, pls. 9-12.
https://doi.org/10.5962/bhl.part.1473
indochinese nemacheilines. A revision of nemacheiline loaches (Pisces: Cypriniformes) of thailand, Burma, Laos, Cambodia and southern Viet Nam
- M Kottelat
Kottelat, M. (1990) indochinese nemacheilines. A revision of nemacheiline loaches (Pisces: Cypriniformes) of thailand, Burma, Laos, Cambodia and southern Viet Nam. Pfeil, München, 262 pp.
- M Kottelat
Kottelat, M. (2012b) Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidea).
Raffles Bulletin of Zoology, Supplement 26, 1-199.