Emarginate Caudal Fin Research Articles

Revision of the Oxynoemacheilus angorae group with the description of two new species (Teleostei: Nemacheilidae).

The Oxynoemacheilus angorae species group is revised and 10 species are recognised, two of which are described herein as new. Oxynoemacheilus anatolicus, O. angorae, O. eregliensis, O. germencicus, O. isauricus, O. nasreddini, O. mediterraneus, and O. theophilii are endemic to west and Central Anatolia. Oxynoemacheilus cinicus and O. mesudae, both from Byk Menderes River drainage, are synonyms of O. germencicus. As First Revisers, we give priority to Oxynoemacheilus germencicus over O. cinicus. Oxynoemacheilus atili described from Lake Beyehir basin is a synonym of O. eregliensis. Oxynoemacheilus axylos, new species, from endorheic Lake Tuz basin (Cihanbeyli, Glyaz, Melendiz, and Samsam) is distinguished by possessing an almost truncate caudal-fin, a stout caudal peduncle, and elevated dorsal and ventral adipose crests. The new species is also distinguished by a minimum K2P sequence divergence of 1.6% in the mtDNA-COI barcode region from O. eregliensis, its closest relative. Oxynoemacheilus eliasi, new species, from the Kk Menderes and Gediz River drainages, is distinguished by having small, embedded scales on the belly, a narrow suborbital groove in male, an emarginate caudal fin, the caudal peduncle depth 1.31.5 times in its length, and the body depth decreasing between the dorsal and caudal-fin bases. The new species is also distinguished by a minimum K2P sequence divergence of 2.7% in the mtDNA-COI barcode region from O. theophilii, its closest relative.

A new catfish of the genus Trichomycterus from the Rio Paraíba do Sul Basin, south-eastern Brazil, a supposedly migrating species (Siluriformes, Trichomycteridae)

A new species of the catfish genusTrichomycterusis described from the Rio Paraíba do Sul, south-eastern Brazil. This species exhibits some morphological character states that are unique amongst congeners, including a robust opercle and a long interopercle with numerous odontodes (50–60 opercular and 90–100 interopercular), a black bar on the basal portion of the caudal fin and a dark brown flank with a well delimited dorsal yellow stripe. It also exhibits some morphological traits that are uncommon amongst congeners, such as the presence of nine pectoral-fin rays. The presence of a shallow hyomandibular outgrowth and a ventrally expanded pre-opercular ventral flap suggests that this species is closely related toT. melanopygius,T. pradensisandT. tete. The new species also differs fromT. melanopygius,T. pradensisandT. teteby having an emarginate caudal fin and a single median supra-orbital pore S6. Anecdotal evidence suggests thatT. largoperculatusandT. pradensishave migratory habits, a condition not previously reported for eastern South American trichomycterines.

Oxynoemacheilus fatsaensis, a new nemacheilid loach from the Elekçi Stream in Northern Anatolia (Teleostei: Nemacheilidae)

We report a new species, Oxynoemacheilus fatsaensis, from the Elekçi Stream, a small stream that flows to the Black Sea in Northern Turkey. It is distinguished from other Oxynoemacheilus species in the Black Sea, Upper Euphrates, and Kura-Aras River basins by having a suborbital groove in males, an axillary lobe at the pelvic-fin base, no dorsal adipose crest on the caudal peduncle, a deeply emarginate caudal fin, small inner and outer rostral barbels, and mottled flank pattern. Molecular data suggest that the new species is separated by a minimum p-distance of 3.3% from O. banarescui in the mitochondrial DNA COI barcode region.

Oxynoemacheilus nasreddini, a new nemacheilid loach from Central Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus nasreddini, new species, from Lake Akşehir, Eber, Eğirdir, and Ilgın basins in Central Anatolia is distinguished from other species of Oxynoemacheilus in Central Anatolia by having irregularly shaped blotches on flank; 24 dark-brown bands on caudal fin; a slender body, and an emarginate caudal fin in which the shortest middle caudal-fin ray is 7691% of the longest ray of the upper caudal-fin lobe. Molecular data suggest that the new species is closely related to O. mediterraneus from the Aksu and Köprüçay drainages. Although the two species are separated by only a minimum K2P distance of 1.2% in the mtDNA COI barcode region, they are well distinguished morphologically. The situation is complicated by loaches from Lake Eğirdir basin that are identified as O. nasreddini by their morphological character states but are only distinguished from O. mediterraneus by a minimum K2P distance of 0.2% in the mtDNA COI barcode region.

EmOxynoemacheilus/em emphasicus/em, a new nemacheilid loach from the eastern Black Sea basin with some remarks on other Caucasian emOxynoemacheilus/em (Teleostei: Nemacheilidae).

Oxynoemacheilus phasicus, new species, is described from the Rioni and Enguri River drainages in Georgia. It is distinguished from other Oxynoemacheilus species in the O. brandtii group by a mottled or marbled flank pattern in adults, a slightly emarginate caudal fin, and a deep caudal peduncle. Molecular data suggest that the new species is characterized by a minimum K2P distance of 7.5% from O. brandtii from the Kura drainage in the mtDNA COI barcode region. Oxynoemacheilus brandtii and O. elsae are re-diagnosed. A very slender Oxynoemacheilus from the Aras drainage clusters as sister to O. elsae in our molecular analysis and not with O. brandtii from the Kura River. However, it is identified as O. brandtii as it is indistinguishable from this species in morphological characters.

Oxynoemacheilus amanos, a new nemacheilid loach from the Orontes River drainage (Teleostei: Nemacheilidae).

Oxynoemacheilus amanos, new species, is described from İncesu spring in the upper Hupnik drainage, a northern tributary of the lower Orontes in Turkey. It is distinguished from the other Oxynoemacheilus species in the Eastern Mediterranean Sea basin by possession of an incomplete lateral line with 23-45 pores, terminating between the vertical through the dorsal fin origin and the anus, 10-13 pores in the infraorbital canal, a deeply emarginate caudal fin, no suborbital groove in the male, and a series of irregularly shaped and set dark-brown bars on the flank, not connected to saddles on the back.

Oxynoemacheilus shehabi, a new nemacheilid loach from the upper Orontes in southern Syria (Teleostei: Nemacheilidae).

Oxynoemacheilus shehabi, new species, is described from the upper Orontes in southern Syria. It is distinguished from other Oxynoemacheilus species in the Levant by possession of a complete lateral line, a deeply emarginate caudal fin, a narrow caudal peduncle, a suborbital groove in male individuals, a well-developed pelvic axillary lobe, and 5-7 dark-brown bars on the flank. Molecular data suggest that the new species is characterised by a minimum K2P distance of 3.8% to O. "seyhanicola" in the COI mtDNA barcode region.

Oxynoemacheilus cilicicus, a new nemacheilid loach from the Göksu River in southern Anatolia (Teleostei: Nemacheilidae)

Oxynoemacheilus cilicicus, new species, is described from the Göksu, Seyhan and Ceyhan rivers in southern Turkey. It is distinguished from other Oxynoemacheilus species in the Eastern Mediterranean Sea basin by possession of an incomplete lateral line, terminating before the vertical of the dorsal-fin origin or slightly behind the dorsal-fin base, a deeply emarginate caudal fin, no suborbital groove in male individuals, and a series of dark-brown bars on the flank not interrupted along the lateral line. Molecular data suggest that Oxynoemacheilus cilicicus is characterised by 22 variable nucleotide substitutions and a minimum K2P distance of 4.09% with O. panthera in the mtDNA COI barcode region.

Schistura syngkai, a new fish species (Teleostei: Nemacheilidae) from Meghalaya, northeast India.

Schistura syngkai, a new stone loach, is described from the Twahdidoh Stream of Wahblei River (Surma-Meghna drainage) in Meghalaya, northeast India. It is unique among its Indian congeners in having a prominent dark-brown to blackish mid-lateral stripe about an eye diameter or more in width, overlain on 12-18 vertically-elongate black blotches on a golden-brown to amber body. Additionally, the species possesses an incomplete lateral line and a slightly emarginate caudal fin, and exhibits no apparent sexual dimorphism.

Rhyacoschistura larreci, a new genus and species of loach from Laos and redescription of R. suber (Teleostei: Nemacheilidae).

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.

Schistura madhavai, a new species of hill-stream loach from Sri Lanka, with redescription of S. notostigma (Teleostei: Nemacheilidae)

Schistura madhavai, new species, is described from Suriyakanda, Sri Lanka. It is distinguished from all other species of Schistura in the peninsula of India and Sri Lanka by the combination of the following characters: 8–9 wide, brown postdorsal bars separated by narrow, white interspaces; width of interspaces ¼–⅓ times width of bars; black bar at caudal-fin base wider than interspaces on the body; incomplete lateral line, ending beneath dorsal-fin base; absence of an axillary pelvic lobe; adpressed pelvic fin just reaching anus; origin of the pelvic fin on a vertical through the last unbranched dorsal-fin ray. Schistura notostigma, the only other Sri Lankan species of Schistura, is redescribed. It can be distinguished from all other species of Schistura in the peninsula of India and Sri Lanka by the combination of the following characters: 6–7 wide, brown postdorsal bars; width of interspaces ½–1 times width of bars; complete, black bar at caudal-fin base narrower than width of interspaces between bars on body; emarginate caudal fin; incomplete lateral line ending beneath dorsal-fin base; adpressed pelvic fin surpassing anus; and origin of pelvic fin beneath first branched dorsal-fin ray. Schistura madhavai is separated from S. notostigma by an uncorrected pairwise distance of 3.0–3.8% for the 16S rRNA gene fragment.

Oxynoemacheilus zarzianus, a new loach from the Lesser Zab River drainage in Iraqi Kurdistan (Teleostei: Nemacheilidae).

Oxynoemacheilus zarzianus, new species, is described from the Lesser Zab River drainage, a tributary of the lower Tigris. It is distinguished from other Oxynoemacheilus species in the Tigris drainage by having a slightly emarginate caudal fin, no suborbital groove in males, a complete lateral line, the posterior process of the bony air-bladder capsule directed posteriorly, the flank and posterior part of back covered by scales, short barbels and a deep caudal peduncle. It is the fourth Oxynoemacheilus species known from the Lesser Zab drainage, where such loaches seem to be highly isolated in headwaters. Oxynoemacheilus species diversity in the Euphrates and Tigris drainage is exceptional high. Today 22 species are known from the entire Euphrates and Tigris drainage and 15 from the Tigris drainage alone.

Oxynoemacheilus hazarensis, a new species from Lake Hazar in Turkey, with remarks on O. euphraticus (Teleostei: Nemacheilidae).

Oxynoemacheilus hazarensis, new species, from Lake Hazar in the Turkish Tigris drainage, is distinguished from other Oxynoemacheilus in the Tigris drainage by having the combination of a slightly emarginate caudal fin, no suborbital groove in males, an incomplete lateral line, no scales on the back and flank in front of the anus, the maxillary barbel reaching beyond the middle of the eye, an incision in the middle of the upper lip, and the colour pattern on the flank mottled, not interrupted by an unpigmented zone along the lateral line. Oxynoemacheilus euphraticus from the Euphrates and Tigris drainages is a valid species: it is discussed and re-diagnosed against O. argyrogramma.

Two new species of Oxynoemacheilus from the Tigris drainage in Iraqi Kurdistan (Teleostei: Nemacheilidae).

Two new species of Oxynoemacheilus are described from the Sirvan River drainage in Iraqi Kurdistan. Oxynoemacheilus gyndes, new species, is distinguished by having a very short lateral line, reaching behind the pectoral-fin base, no scales except on the posteriormost part of the caudal peduncle, a slightly emarginate caudal fin and no suborbital groove in males. Oxynoemacheilus hanae, new species, is distinguished by having a midlateral row of elongated blotches, isolated patches of dark-brown spots or blotches on lower flank, a deeply emarginate caudal fin and a suborbital groove in males.

Schistura andrewi, a new species of loach (Teleostei: Nemacheilidae) from Mizoram, northeastern India.

Schistura andrewi, a new species of loach, is described from a tributary of Kaladan River in Mizoram, northeastern India. It is distinguished from its congeners in having the following combination of characters: long axillary pelvic lobe; complete lateral line with 82-95 pores; 2 unbranched dorsal and anal fin rays; 6-7 broad, wider than interspace, black bars on the body; 2 rows of black spots horizontally across the dorsal fin; a deeply emarginate caudal fin, with 2 vertical rows of black spots across the fin, and 9 + 8 branched caudal fin rays.

Schistura maculosa, a new species of loach (Teleostei: Nemacheilidae) from Mizoram, northeastern India.

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.

A new species of the hoplichthyid genus Hoplichthys (Teleostei: Hoplichthyidae) from northern Western Australia.

A new species of hoplichthyid, Hoplichthys imamurai, is described on basis of three specimens (128.9-143.6 mm SL) collected from northern Western Australia. It is clearly distinguished from its congeners by the following combination of characters: short preoptic snout (31.2-32.7% HL); vomer without teeth; long, thin, gill rakers; low first dorsal fin, its ad-pressed tips not reaching origin of second dorsal fin in males; some filament-like elongated second dorsal-fin rays in males; emarginate caudal fin, upper edge elongated and filament-like in males. Toothless vomer and form of caudal fin are characters unique to H. imamurai in this genus.

Neolamprologus longicaudatus, a New Cichlid Fish from the Zairean Coast of Lake Tanganyika

A new cichlid, Neolamprologus longicaudatus sp. nov. is described, based on three specimens from the north Zairean coast of Lake Tanganyika. Although similar to N. furcifer, N. christyi and N. buescheri in having an elongate body, strongly emarginate caudal fin, and vertical fins partly covered with scales, this species is distinguishable from them by its small orbit, light grayish-brown coloration of body, dorsal fin lacking a submarginal dark band, 37 longitudinal body scales, 8 gill rakers on lower limb of the 1st gill arch, and a long pointed snout.

Akysis fontaneus, a new species of catfish (Siluriformes: Akysidae) from Sumatra

Akysis fontaneus, new species, is described from a spring-fed stream in the Batang Hari drainage in central Sumatra. It is distinguished from congeners in having a unique combination of the following characters: weakly emarginate caudal fin, convex dorsal surface of neurocranium making predorsal profile appear steeply sloping, presence of 4 large serrations on posterior edge of pectoral spine that are more than half width of spine, predorsal length 34.5% SL, pectoral-fin length 21.7% SL, length of adipose-fin base 18.7% SL and interorbital distance 42.3% HL. Akysis fontaneus is most similar to A. heterurus, also from the Batang Hari River drainage, but the differing morphology of the predorsal area (particularly the neurocranium) and shorter pectoral fin distinguishes it from A. heterurus.

Two New Species of the Akysis Variegatus Species Group (Siluriformes: Akysidae) from Southern Sumatra and a Redescription of Akysis Variegatus Bleeker, 1846

Two new species of Akysis from Sumatra are described, and A. variegatus, the type species of Akysis, is redescribed. All three species are members of the A. variegatus species group, characterized by a space between the anterior nostril and the base of the nasal barbel that is about equal to the diameter of the anterior nostril, relatively small anterior and posterior nostrils (with a diameter less than that of the eye), the anterior nostril located at the end of a short tube, subequal jaws, and an emarginate caudal fin. The two new species are morphologically similar to one another but differ dramatically in the sculpturing on top of the head.