Contribution to the trout of Euphrates River, with description of a new species, and range extension of Salmo munzuricus (Salmoniformes, Salmonidae)

In an effort to reveal the Euphrates trout taxonomy, the Karasu River, which is one of the eastern drainages of the river, was investigated and three independent populations were identified. Result revealed that two populations belonged to Salmo munzuricus, which was known only in Munzur River, while the other population belonged to an unnamed species. Salmo baliki, a new species, is described from the Murat River, a drainage of Euphrates River. It differs from Salmo species in adjacent water by the combination of the following characters: a grayish body; commonly one, rarely two pale black spots behind eye and on cheek; two to seven black spots on opercle; a few black spots on back and upper part of flank, missing on predorsal area; few to numerous large irregular-shaped red spots in median, upper and lower part of flank, surrounded by a large irregular-shaped white ring; the number of black and red spots not increasing in parallel with size; maxilla short and narrow; adipose-fin medium size, no or rarely one or two red spot its posterior edge; 107–118 lateral line scales; 24–28 scales rows between dorsal-in origin and lateral line; 18–22 scale rows between lateral line and anal–fin origin; maxilla length 7.7–9.1% SL in males, 8.2–9.6 in females. Finally, the genetic study of the Cyt b mitochondrial gene confirmed the morphological data, suggesting the separation of S. baliki from other Salmo species.

Pseudobagarius eustictus, a new species of catfish from northern Laos (Siluriformes: Akysidae)

Pseudobagarius eustictus, new species, is described from the Nam Heung drainage (a tributary of the Mekong River) in northern Laos. It is distinguished from congeners in having a unique combination of the following characters: a weakly-produced snout in which the upper jaw extends only slightly beyond the margin of the lower jaw when viewed ventrally, 3 tubercles on the posterior margin of the pectoral spine, eye diameter 8% HL, head width 24.1% SL, dark yellow dorsal and lateral surfaces of the head, pectoral spine lacking elongate extensions, pectoral fin reaching the pelvic-fin base when adpressed against the body, dorsolateral surfaces of body without longitudinal series of prominent tubercles, body depth at anus 13.7% SL, length of adipose-fin base 17.7% SL, caudal-peduncle depth 7.0% SL, and 33 vertebrae.

The Glyptothorax catfishes of the Euphrates and Tigris with the description of a new species (Teleostei: Sisoridae)

The Glyptothorax species inhabiting the Euphrates and Tigris drainages are reviewed and six species are recognised, one of which is described herein as new species. Glyptothorax armeniacus is endemic to headwater streams in the Euphrates drainage. Glyptothorax kurdistanicus is endemic to the upper Tigris downstream to the Lesser Zab drainage. Glyptothorax cous and G. steindachneri are riverine species widespread in both the Euphrates and Tigris drainages. Glyptothorax silviae is endemic to Iran. Glyptothorax daemon, new species, from the Greater Zab and Yanarsu in the upper Tigris drainage, is distinguished by having the thoracic adhesive apparatus strongly elevated, 1.1–1.2 times longer than wide, without tubercles on the head, well developed anteromedial striae, the medial pit without striae, and a short adipose fin. Glyptothorax daemon is separated into two mitochondrial lineages, externally indistinguishable and separated by a minimum K2P distance of 2.0% in the DNA barcode region. These lineages are paraphyletic in our analysis indicating past introgressive hybridisation with G. cous. All six species are diagnosed and all, except unstudied G. steindachneri, form distinct mitochondrial clades with between 1.2% and 3.4% minimum K2P distance between them. Species from the Euphrates and Tigris form a monophyletic mitochondrial group separated from 53 other Glyptothorax species studied from India and areas further east.

Liobagrus huaiheensis, a new species of torrent catfish (Teleostei: Siluriformes: Amblycipitidae) from the Huaihe River basin in Central China

Liobagrus huaiheensis, a new species of catfish, is described from the Shihe River, a tributary of the Huaihe River, in Henan Province, Central China. It shares a serrated posterior edge of the pectoral-fin spine with L. marginatus, L. nigricauda, L. kingi, L. chenghaiensis, L. andersoni, L. mediadiposalis, L. obesus, L. somjinensis, and L. hyeongsanensis, but it is distinguished from these nine species by having combination of the following characters: 2–3 serrations on the posterior edge of the pectoral-fin spine; 15–17 anal-fin rays; an upper jaw longer than lower one; a rounded caudal-fin with 50–55 rays; 35–37 post-Weberian vertebrae; anus close to pelvic-fin insertion and an adipose-fin posteriorly continuous with caudal-fin, with a marked incision at confluence.

Early ontogeny of Pimelodus blochii Valenciennes, 1840 (Siluriformes: Pimelodidae): Neotropical catfish

Larval ontogeny of the long-whiskered catfish Pimelodus blochii Valenciennes, 1840 is described, providing useful characters for identification and determining the growth pattern throughout its development. Eighty-nine larvae classified in three stages (preflexion, flexion and postflexion) and 30 juveniles were analyzed, totaling 119 individuals. The specimens were collected monthly from January 2013 to May 2019 in the lower Amazon river. A suite of morphological, morphometric, and meristic data was used to describe the stages of development. Three analytical regression models were used: simple linear, quadratic and piecewise regressions. The larvae are characterized by small to moderate eyes, subinferior mouth, and long barbels (maxillary larger than the mental barbels), triangular-shaped adipose fin, and the final part of the intestine reaching half the body. Pigmentation consists of dendritic chromatophores distributed irregularly in the body, ventral region and head, intensifying in the flanks and dorsal region throughout development. The total number of myomeres has a mode of 42 muscle bundles, ranging from 40 to 42 (15 to 16 pre-and 25 to 26 post-anal) and the number of fin segments corresponded to: pectoral = I + 9, pelvic = 6, dorsal = I + 6 and anal = 11–12. All body variables showed discontinuous isometric growth, indicating a deceleration in the structural modeling of the body, between the flexion/post-flexion stages and acceleration in post-flexion/early juvenile period. Precisely when the formation of the fin rays, muscles and organs of the digestive system and ossification are observed, suggesting low morphological variation during ontogenetic development. Pimelodus blochii differs from other congeneric species in the lower Amazon river by meristic characters, which helps to correctly identify individuals in early stages of development.

Description of Bagarius vegrandis, a new species of sisorid catfish from Indochina (Actinopterygii: Siluriformes), with notes on the identity of Bagarius bagarius

Bagarius vegrandis, new species, is described from the Chao Phraya and Mekong river drainages. It differs from congeners in having a small maximum body size (to 220 mm SL vs. 520–1400 mm SL) and the adipose-fin origin markedly posterior to (vs. at vertical through or very slightly posterior to) the anal-fin origin. It further differs from congeners in having the following unique combination of characters: ovoid unculiferous plaques on dorsal surface of head, lateral margin of frontal not significantly deflected dorsally, eye diameter 11–15% HL, interorbital distance 23–28% HL, head width 18.3–22.3% SL, head depth 11.1–14.1% SL, filamentous extensions to first pectoral-fin element reaching to anus, dorsal spine width 10.6–13.9 times in its length, body depth at anus 8.7–12.0% SL, neural spines of the 4–6 vertebrae immediately anterior to adipose fin distally flattened but not forming series of prominent bumps along dorsal midline, length of adipose-fin base 10.8–13.0% SL, caudal-peduncle length 19.0–22.4% SL, caudal-peduncle depth 3.2–4.2% SL, 19–20 preanal vertebrae, and 39–40 total vertebrae. Bagarius bagarius (Hamilton, 1822) is demonstrated to be a species restricted to the Indian subcontinent (with Bagrus yarrelli Sykes, 1839, Pimelodus platespogon Valenciennes, in Jacquemont, 1839 and Pimelodus carnaticus Jerdon, 1849 as junior subjective synonyms) and Bagarius lica Volz, 1903 resurrected from synonymy with B. yarrelli as a valid species from Southeast Asia.

A new, narrowly distributed, and critically endangered species of Characidium (Characiformes: Crenuchidae) from the Distrito Federal, Central Brazil

ABSTRACT A new species of Characidium is described from the Cerrado biome, in Brasília, Distrito Federal, Central Brazil. The new species can be readily diagnosed by the presence of two or three longitudinal rows of dots along the body sides, absence of bars, by the short pectoral fin, which does not reach the vertical through the dorsal fin origin. Additional useful diagnostic characters are the scaled isthmus, absence of the adipose fin, and the terminal mouth. The new species is only known from the córrego Taquara and its tributaries, a tributary of ribeirão do Gama, upstream from lago Paranoá, in the upper rio Paraná basin. In accordance to the IUCN Red List Categories and Criteria, the new species is categorized as Critically Endangered.

Comparative genetic and morphometric characterization of sympatric populations of Heterobranchus bidorsalis and Heterobranchus longifilis

African catfish species of Heterobranchus longifilis and H. bidorsalis are gaining breeding potentials and receiving great attention among catfish stakeholders. However, very few comparative research works have been done on the natural populations and cultured stocks of these economically important species. In this study, the genetic evaluation of the fish species populations obtained from Lake Kainji, New Bussa, Niger State, Nigeria, was conducted through Sodium Dodecyl Sulphate - Polyacylamide Gel Electrophoresis oftheir serum proteins, and morphometric evaluation. Morphometric data showed that adipose fin attributes [length; depth (cm), % standard length (SL)] of 23.4±1.1; 4.2±0.5 in the H. bidorsalis confirmed its hyper-development compared to H. longifilis of 25.7±3.2; 4.4±0.6 respectively. The pre-dorsal length gave higher value (%SL) in the H. longifilis (38.6±2.2) than H. bidorsalis (34.6±1.2); while H. bidorsalis further possessed more counts at dorsal and anal fin rays than H. longifilis. The comparative dendrogram of the PAST analysis showed a genetic distance of 4.2% that indicated the specificity of these species and, though significantly different, they had very close relationship. Therefore, proper identification of these species is highly necessary to maintain genetic purity in breeding programmes and biodiversity.

Description of a new species of Hisonotus (Loricariidae: Siluriformes) from rio Araguaia basin

A new species of Hisonotus is described from headwaters of rio Araguaia basin, municipality of Barra do Garças, Mato Grosso state, Brazil. The new species is distinguished from its congeners by a V-shaped spinelet, yellowish teeth, absence of unpaired platelets at typical adipose fin position, the caudal-fin color hyaline with three transverse dark bars, one abdominal median plate series, and by morphometric and meristic characters.

A new species of Characidium Reinhardt (Characiformes: Crenuchidae) with a unique mid-water behavior from the upper rio Madeira basin, Brazil

A new species of Characidium is described from headwater tributaries of the upper rio Guaporé, Rio Madeira basin, Mato Grosso state, Brazil. The new species can be diagnosed from all congeners, except Characidium summus, for lacking the preorbital and postorbital stripes. It can be diagnosed from the latter species by having 12 circumpeduncular scales (vs. 14), by an adipose fin present (vs. adipose fin absent), and 10–12 bars along the body (vs. absence of bars), among other characters. The new species is so far only known from direct tributaries of the Rio Guaporé at the Serra da Borda, an isolated plateau 300–800 meters above sea level, and possess a behavior very uncommon within the genus, being a mid-water pelagic fish, instead of the benthic behavior of most congeners. Comments on the putative phylogenetic relationships of the new species, as well as some remarks on its unusual behavior within the genus, are presented.