A new Myloplus is described from the Tocantins-Araguaia basin. The new species is distinguished from its congeners, except from M. levis, by having a black marking on the distal portion of the anterior anal-fin rays. It differs from M. levis by having 19-21 branched dorsal-fin rays (vs. 23-27). The new species is widely distributed throughout the upper and middle reaches of the Rio Tocantins basin, and also the Rio Araguaia and its tributaries.
Two new Chinese species of Gobiobotia are described from southern China. Both are placed in the species group having an unscaled region of the abdomen adjacent to the ventral midline extending to pelvic-fin insertions. Gobiobotia incarinatus, from the Gan-Jiang in Jiangxi Province, is distinguished from other species of the group by a combination of more vertebrae, more lateral-line pored scales and non-keeled scales on the predorsal body above the lateral line. Gobiobotia bouommatos, from the Liu-Jiang in Guangxi Province and the Yuan-Jiang in Hunan Province, is distinguished from other members of this group with fewer vertebrae, fewer lateral line pored scales and its colour pattern exclusive of G. paucirastella, further from G. paucirastella by keeled scales on the predorsal body above the lateral line. A molecular phylogenetic analysis based on the cytochrome b gene and significant genetic distances with sampled congeneric species support the specific distinctness of the two new species. The specific status of G. intermedia, G. fukiensis and G. yuanjiangensis is also scrutinised based on our examination of type material and molecular evidence.
Limbochromis robertsi is an endangered freshwater cichlid fish species with a distribution limited to the upper tributaries of the Pra River in Eastern Ghana. The land cover in most parts of its range has undergone substantial changes. Deforestation and forest fragmentation in the Eastern Region of Ghana accelerated dramatically in the last 20 years, with the majority of the forest loss along the banks of rivers and creeks due to artisanal small-scale mining (primarily for gold) and agriculture. Field surveys showed a decrease in the total population of L. robertsi by more than 95 % from the early 1990s to 2021. A small population which has been found about 20 years ago in the Western Region of Ghana was not found again. Because of the great decline of the species a stronger conservation and conservation status for it are suggested, as well as breeding programs combining in-situ and ex-situ methods. Potential habitats for re-establishing populations of L. robertsi were also investigated.
A new species of Hypostomus with blunt head is described from the medium and upper portions of the Rio Tocantins basin in Central Brazil. The new species inhabits rocky-bottom, small to large rivers of the Rio Tocantins basin and reaches moderate full size. The new species can be distinguished from all its congeners mainly by having teeth crowns with ellipsoidal medial cusp, deep and moderate body size, large eyes, absence of keels on lateral series of plates, large and faded dark blotches over a clearer body background, and by having a flap-shaped median buccal papilla.
A new species of swamp eel, Ophichthys terricolus, is described from Assam, India. The new species closely resembles the common Ophichthys cuchia but differs from this species by having fewer abdominal vertebrae (79-80 vs. 95-100), a longer preanal and shorter postanal region, and a wider and higher posterior part of the body.
Sensory organs are generally fine-tuned to an organism's environment and ecological niche. Many examples of this environmentally influenced fine-tuning exist for sensory modalities, such as vision and audition, but this link is poorly understood for electroreception. This study investigates the distribution of electroreceptor pores on the heads of select members of the Gymnotiformes, Neotropical weakly electric knifefishes that use electric signals for orientation, communication, and prey localization. We evaluated the distribution and density of electroreceptors among select gymnotiform genera and discuss whether apparent differences could be consistent with ecological factors, such as habitat type and feeding behavior. Evidence for such patterns has been found in elasmobranchs; however, differences in the functional roles of the electrosensory system in gymnotiforms (e. g. electrocommunication) may alter these patterns within this diverse clade of freshwater fishes. Scanning electron microscopy was used to image the heads of specimens collected from diverse habitats. Pores associated with ampullary and tuberous electroreceptor organs were enumerated using digital image processing software and mean pore counts were compared across six different regions of the head. Previously unknown pore types and distribution patterns are described. Additionally, unique electroreceptor distributions were found in some species with specialized feeding modes. This study provides the first quantitative comparative analysis of electroreceptor distributions across multiple gymnotiform families and genera, providing an important step toward understanding the factors that have shaped the evolution of electroreception in this diverse group of Neotropical fishes.
A new species, Enteromius baleensis , is described from the Weyb River basin, Juba River system, Bale Mountain Region in southeastern Ethiopia. It differs from all other Enteromius in having the last unbranched dorsal-fin ray soft and flexible, scales moderately small (34 - 37 in lateral series), and incomplete lateral line. Molecular data (cytochrome b) reveal its inclusion as a new species in the E . pleurogramma species complex, widely distributed in Ethiopia. Furthermore, six other distinct lineages deserving the species status are also defined by molecular analysis inferred from cytochrome b sequences. From these lineages, only three have been named: E . akakianus (Central Rift Valley), E . pleurogramma (Lake Tana) and E . yardiensis (Afar Depression). Based on molecular data, Enteromius baleensis is sister to E . akakianus . Based on morphological features, E . baleensis is remarkably different from the other representatives of the E . pleurogramma complex by combining soft and flexible last unbranched dorsal-fin ray and incomplete lateral line, and by a number of the skeletal reductions. The new species is the only member of the E . pleurogramma complex inhabiting the Indian Ocean catchment in Ethiopia. It should be considered for protection as a narrow-range endemic species based on its current restricted distribution in the Weyb River basin.
Triplophysa qini , a new stygobitic fish, is described from two subterranean pools (in the Wu-Jiang of the upper Chang-Jiang basin) located in Wulong and Fengdu counties, Chongqing City, Southwest China. It exhibits a concave distal margin of the dorsal fin and absence of nasal barbels; two characters that combined differentiate it from all congeners of the eyeless group except T. qiubeiensis . The new species differs from T. qiubeiensis in the number of branched dorsal-fin rays (9 vs. 8) and in the shorter head. The specific status of T. qini is confirmed by its significant sequence divergence for the cyt b gene with sampled congeneric species, particularly those coexisting in the mid-upper Chang-Jiang basin, and by its monophyly recovered in a cyt b gene-based phylogenetic analysis.
Since 1996, in field monitoring for the construction of the Manso Reservoir in the Rio Manso basin, a peculiar black -blotched morphotype of Hypostomus was found that differed from several congeners from the region. This species is already used to aquarium trade being labeled Hypostomus sp. L233. The aim of the present work is to describe L233 as a new species to science, Hypostomus fuscomaculatus . The new species is distinguished from congeners by having conspicuous, large (usually larger than eye diameter) and widely spaced black blotches on living specimens. In preserved specimens, the blotches usually fade to brown but keep still evident for a long time under proper fixation and storage. Other important diagnostic traits are the flattened head, large eyes, absence of keels on lateral series of plates, robust and moderate number of teeth, and plates covering most part of abdominal region.
Barbus ida, a new species, is described from the streams G & ouml;nen and Biga, in western Anatolia. It is distinguished from other Barbus species in the adjacent basins by a less thickened last unbranched dorsal-fin ray, serrated along the proximal half of its posterior margin; larger irregular black blotches on the back and the flanks, and small black spots on the head, extending downwards to the cheeks; 56 - 61 total lateral line scales, 11 - 13 scale rows between dorsal-fin origin and lateral line and 7 - 8 scale rows between anal -fin origin and lateral line. Barbus ida also differs from its most closely related species, B. niluferensis , by 8 nucleotide substitution sites in the mtDNA cytochrome oxidase I barcode region.
Steatocranus masalamasoso , a new species of small rheophilic cichlid species, is described from the Masala Ma Soso Rapids on the L & eacute;fini River, Central Congo basin. It is distinguished from its congeners by the number of circumpeduncular scales (18 - 20 vs. 12 - 16). The construction of a hydroelectric dam on the L & eacute;fini River, located at about 3 km upstream of the type locality of S . masalamasoso and operational since 2009, resulted in the inundation of the Masala Ma Soso Rapids. Recent efforts to collect S . masalamasoso failed, suggesting that adverse downstream effects of the dam on the original habitat, may have led to the demise of the species.
Paracanthocobitis epimekes, new species, is described from the Tenasserim and Lenya river basins in Tanintharyi Province, Myanmar, and the Takua Pa River basin in Phang Nga Province, Thailand. Paracanthocobitis epimekes is genetically the sister species of all other species in the P. zonalternans species group and co-occurs with P. phu ketensis in most known localities. Paracanthocobitis epimekes differs from all other species of Paracanthocobitis by the combination of an incomplete lateral line, a relatively elongated body, an absent or rudimentary axillary pelvic lobe, 9 1/2 or 10 1/2 branched dorsal -fin rays, a unique pigmentation pattern, and a suborbital flap in adult males.
We studied in detail the head and shoulder girdle skeleton and vertebral column of the holotype of the Mexican endemic swamp eel Ophisternon infernale . This exclusively subterranean species lives in waters inside lime stone caves in Yucat & aacute;n. Its skeleton shows a number of putative plesiomorphic characters in relation to those of Oph ichthys , Rakthamichthys and Typhlosynbranchus : I. In Ophisternon infernale , the basisphenoid is present and well developed. II. In Ophisternon infernale , the dermal shoulder girdle is complete and the posttemporal articulates with the skull. III. In Ophisternon infernale , the basibranchial series is complete and includes basibranchials 1-3. IV. In Ophisternon infernale , the hypobranchials and ceratobranchials are in a typical position with hypobranchials articulating with their respective ceratobranchials. V. In Ophisternon infernale , hypobranchials 2 do not articulate with each other in the midline, but are separated by basibranchials 2 and 3. VI. In Ophisternon infernale , the urohyal is narrow and elongated reaching from the basihyal-hypohyal articulation to the anterior tip of basibranchial 3. VII. Ophisternon infernale has a complete set of upper gill arches comprising epibranchials 1-4, an interarcual bone, pharyngobranchials 2 and 3, upper pharyngeal toothplate 4 and with epibranchials 3 and 4 articulating with each other via uncinate processes.
Garra laishrami , a new cyprinid fish, is described from the Godavari River drainage in Odisha, India. It is distinguished from all its congeners in the Indian sub-continent in having a combination of the following characters: a weakly developed bilobed proboscis, each lobe with 1-4 unicuspid acanthoid tubercles; transverse lobe of the snout covered with 33-47 medium- to large-sized unicuspid acanthoid tubercles; transverse groove demarcating transverse lobe on snout extended laterally; two prominent tubercles anteromedially between nostrils; 9-10 predorsal scales; lateral line complete, scales along lateral line (28-32) + 2 on caudal-fin base; and 15 circumpeduncular scale rows.
Parananochromis moutingae, new species, is the first species of Parananochromis to be recorded as endemic to the Congo Basin. It is recorded from the Lefini, Lebomo, and Mayi Ndombe Rivers in the middle Congo. Paranano chromis moutingae is distinguished from all congeners by a unique combination of the following meristic and morphological characters: three tubular infraorbital bones; a well-developed hanging pad on the pharynx roof; more scales between the dorsal-fin origin and the upper lateral line (5.5-6.5); more small scales between pectoral and pelvic fin insertions (8-10); presence of scales on the chest; more gill rakers on the lower limb of the first gill arch (8-9); more teeth (5-7) on pharyngobranchial 2 of upper pharyngeal jaw; longer snout (32-39 % HL); longer predorsal distance (33.9-36.1 % SL); broader than long lower pharyngeal jaw; straight urohyal spine; and slightly indented ventral margin of the lower pharyngeal keel. Despite concerted efforts, the species has not been collected in the Lefini River since its original discovery in 2008, probably as a result of the installation of a hydroelectric dam, but it seems to subsist in the other two locations.
Hongshuia brevibarba , new species, is described from a small tributary stream of the Qingshui-He (upper ChangJiang basin) in Guiyang City, Guizhou Province, China. It can be distinguished from congeners by a combination of characters, including features of oromandibular structures, head shape and fin coloration. The new species exhibits a genetic distance of 4.2 % to 5.7 % between congeneric species. Hongshuia megalophthalmus is here regarded as a senior synonym of H. banmo .
A new species of sisoroid catfish in the genus Akysis is described from the Mae Klong drainage in western Thailand, marking the first record of this genus there. Akysis patrator , new species, can be distinguished from congeners in having the adipose fin preceded by a long, low ridge contacting the base of the last dorsal-fin ray and a colour pattern of a light brown body with a chocolate brown reticulate pattern on its sides.
We describe a new species of Homatula from the Yangtze River in Yunnan, China based on morphological and molecular analysis. Homatula tigris , new species, differs from the other species of Homatula in the following morphological characters: predorsal body scales sparse; axillary pelvic scale present; lower jaw spoon-shaped and without notch; lateral line complete; gill opening small, its upper angle aligned to lower margin of eye; head length 15.0-17.3 % of SL. The Bayesian inference trees (BI) constructed from Cyt b and COI sequences support the hypothesis of monophyly of H . tigris .
Garra deccanensis , a new species, is described from the Godavari and Krishna Rivers, Andhra Pradesh and Telangana States of India. The new species is distinguished from its congeners in having a combination of following characteristics: snout with a prominent short, unilobed proboscis; 15 -18 small to medium-sized unicuspid acanthoid tubercles on transverse lobe; 31 -32 lateral-line scales; 9 -10 predorsal scales, 16 circumpeduncular scales and two black spots, one at the upper angle of the gill opening and the other behind the median posterior margin of the opercle. Based on mitochondrial cytochrome oxidase subunit 1 gene partial sequence, G. deccanensis differs from all congeners for which genetic data are available by a raw genetic distance of 6.0-17.8 %.
A new catfish of the genus Glyptothorax is described from the Chakpi River, Chindwin drainage of Manipur, India. Glyptothorax waikhomi differs from its congeners in having a mottled skin, an oblanceolate leaf-shaped thoracic adhesive apparatus without a median depression, a serrated dorsal-fin and a short nasal barbel, not extending to anterior margin of orbit.
