Predorsal Scales Research Articles

A new Silver Dollar species of Metynnis Cope, 1878 (Characiformes: Serrasalmidae) from Northwestern Brazil and Southern Venezuela

ABSTRACT A new Metynnis is described from the rio Negro in Brazil and Venezuela, and from black- or clearwater tributaries in Brazil including the rios Parauari, Uatumã, Trombetas, and Sucunduri (the latter belonging to the rio Madeira basin). The new species can be distinguished readily from all congeners by having a high concentration of dark chromatophores on the lateral line scales. It can be further distinguished by the combination of head length 24.3-27.5% of SL, 13-18 gill-rakers on upper limb and 16-24 gill-rakers on lower limb. The new species is most similar to and likely most closely related to Metynnis hypsauchen . These two species share a similar color pattern, body shape and sexual dimorphism of the anal fin. However, they differ in that M. hypsauchen has a lightly pigmented lateral line. The new species is also distinguished from M. hypsauchen by having 56-65 predorsal scales and 90-104 lateral line scales (vs . 36-54, and 65-82, respectively). A detailed osteological description of the new species is provided.

Parambassis serrata, a new species of glassperch (Teleostei: Ambassidae) from the Kaladan drainage, India

Parambassis serrata, a new species of glassperch from the Kolo River, Kaladan drainage, Mizoram, India is described. It is distinguished from its congeners by the combination of characters that includes: presence of a faint, vertically-elongated brown humeral blotch; posterior margin of most spines of first dorsal fin proximally blackish; 14-16 dorsal and anal-fin branched rays; a black longitudinal stripe on ventral surface of caudal peduncle; absence of predorsal scales; a serrated preopercular ridge; 51-56 scales in lateral series; and 11 pectoral-fin rays.

Redescription and osteology of Hyphessobrycon compressus (Meek) (Teleostei: Characidae), type species of the genus

The type-species of Hyphessobrycon is redescribed and its osteology provided. Hyphessobrycon compressus is distinguished from its congeners by the 41-48 (mode 45) scales in the longitudinal series; 7-9 (mode 9) scales rows between the dorsal-fin origin and the lateral line, and absence of predorsal scales. Additional useful characters include the lack of spots on the body, a dorsal fin with a black spot, and an anal fin with two large, conspicuous hooks, and several other small hooks. Hyphessobrycon milleri is proposed as a junior synonym of H. compressus . The osteology of H. compressus is discussed in detail together with comments about phylogenetic relationships of Hyphessobrycon sensu stricto .

Mahseers genera Tor and Neolissochilus (Teleostei: Cyprinidae) from southern Vietnam.

Two new species and two new basin records of mahseers in the genera Tor and Neolissochilus are described from the upper Krong No and middle Đồng Nai drainages of the Langbiang Plateau in southern Vietnam. These new species and new records are known from streams and rivers in montane mixed pine and evergreen forests between 140 and 1112 m. Their populations are isolated in the Sre Pok River of the Mekong basin, the middle of the Đồng Nai basin, and the An Lão River. Both new species are differentiated from their congeners by a combination of the following characters: 23-24 lateral scales, 9-10 predorsal scales, 2/7 or 1/8 pelvic-fin rays, mouth position, median lobe of lower lip, rostral hood, colour in life and by divergent mitochondrial DNA. Tor mekongensis sp. nov. is differentiated from Tor dongnaiensis sp. nov. by the number of transverse scale rows (3/1/2 vs. 4/1/2), number of pelvic-fin rays (2/7 vs. 1/8), a blunt rostral hood vs. pointed, caudal-fin lobes that are equal vs. unequal, and by mitochondrial DNA (0.7% sequence divergence). Molecular evidence identifies both species as members of the genus Tor and distinct from all congeners sampled (uncorrected sequence divergences >1.9% for all Tor species for which homologous COI sequences are available). Tor sinensis is recorded in the Krong No and the Sre Pok rivers, further south of its known distribution. Polymorphism is described in Neolissochilus stracheyi with a Tor-like morph and a Neolissochilus-like morph.

Description of two new species of Laubuka (Teleostei: Cyprinidae) from River Cauvery, southern Iandia.

Fishes currently identified as Laubuka laubuca from the Cauvery River and its tributaries in the Western Ghats of India are shown to represent two different species: Laubuka trevori, sp. nov., and L. latens, sp. nov., distinguished from all species of Chela and Laubuka by possessing 7½ branched dorsal-fin rays; 14 precaudal vertebrae; 17-18 predorsal scales; 5 branched pelvic-fin rays and 5+4+2 teeth on the fifth ceratobranchial. Laubuka trevori is further distinguished from its congeners by possessing 14½-15½ branched anal-fin rays; ½6/1/1½ scales in transverse line on body; a short pelvic fin (10.1-16.3% SL) and two longitudinal stripes: a golden and a bluish-green stripe on the body, running from behind the opercle to the base of the caudal fin, the latter broken and less distinct in the anterior half of the body. Laubuka latens is further distinguished by its long pelvic fin (23.2-26.9% SL) and the absence of any markings on the side of the body other than a humeral spot and a caudal-peduncle spot.

Description of a new species and redescriptions of two rare species of Parapercis (Perciformes: Pinguipedidae) from the tropical Pacific Ocean.

Parapercis johnsoni sp. nov. is described based on 19 specimens from Marquesas Islands, French Polynesia. It differs from congeners in having a combination of the following characters: dorsal-fin rays V, 21; anal-fin rays I, 17; pectoral-fin rays modally 17; pored lateral-line scales modally 52 or 53; predorsal scales 7 or 8; transverse scale rows 3.5 or 4 + 14 or 15; total gill rakers on 1st gill arch 13-16; single row of teeth on vomer; 6 large canines at front of lower jaw; and a distinct coloration. Two rare species, P. flavescens Fourmanoir & Rivaton, 1979 and P. fuscolineata Fourmanoir, 1985, are redescribed based on the types and newly identified specimens. Comments on other species occurring in the area are provided.

Hyphessobrycon natagaima (Characiformes: Characidae) a new species from Colombia, with a key to the Magdalena Basin Hyphessobrycon species

<p>A new species, Hyphessobrycon natagaima, is described from the upper Magdalena River Basin in Colombia. It differs from all other species of Hyphessobrycon with a dark lateral stripe inhabiting the Magdalena River Basin: H. poecilioides, H. proteus and H. ocasoensis, by having eight to twelve pored lateral-line scales (vs. 14-26); four scales between the lateral line and the pelvic-fin insertions (vs. five or six); one tooth on the maxilla (vs. zero in H. poecilioides, and two to five in H. proteus; except H. ocasoensis, with one), a dark, interrupted, lateral stripe that is not in contact with the caudal peduncle spot (vs. absence of caudal spot in H. poecilioides, lateral stripe continued that is in contact with the caudal peduncle spot in H. ocasoensis). It has a rhomboid shaped caudal-peduncle spot that continues on to middle caudal-fin rays (vs. absence of caudal peduncle spot in H. poecilioides and caudal peduncle spot round and not continued on to middle caudal-fin rays in H. ocasoensis); and presence of hooks on all fins in mature males (vs. males with hooks on anal, pelvic and pectoral fins). Hyphessobrycon natagaima differs from H. ocasoensis, in addition to the above characters, by having four scale rows between the lateral line and the anal-fin origin (vs. six); three or four scale rows between the lateral line and the pelvic-fin insertions (vs. six); ten or eleven predorsal scales (vs. nine); i,9,i dorsal-fin rays (vs. ii,8,i); 18-20 branched anal-fin rays (vs. 21-22) and eleven branched pectoral-fin rays (vs. twelve). A key for the identification of Hyphessobrycon species present in the Magdalena River Basin is provided.</p>

Descriptions of three new species of Glossogobius (Teleostei: Gobiidae) from New Guinea

Three new species of Glossogobius are described from New Guinea. Glossogobius multipapillus, n. sp. from northeastern New Guinea has a lobed mental fraenum and a distinctive papilla pattern unlike any other species in the genus. Glossogobius sentaniensis, n. sp. is described from Lake Sentani. The species is similar to Glossogobius aureus and G. koragensis differing in head pores and large dark spots on the body. Glossogobius macrocephalus n. sp. from Lake Tebera and surrounding rivers has a lobed mental fraenum and differs from other species in the Glossogobius celebius group in the combination of having a large head, head pore, fin-ray and predorsal scale counts.

The identity of Hamilton's Ticto Barb, Pethia ticto (Teleostei: Cyprinidae).

While describing the fishes of Ganges, Hamilton described Cyprinus ticto (now allocated to Pethia) from south-eastern parts of Bengal. The unavailability of type material and insufficient diagnostic characters in the original description resulted in ambiguities in the identity of this species. In this paper, we clarify the identity of P. ticto through an integrative-taxonomic approach. Pethia ticto can be distinguished from all other known species of the genus by a combination of characters that includes an abbreviated lateral line with 6-12 pored scales; 23-26 scales in lateral-scale row; 9 predorsal scales; ½4/1/3½-4 scales in transverse series; and a pigmentation pattern that includes a small black humeral spot covering the third and fourth lateral-line scales, a prominent spot on the caudal peduncle on the 16th-19th scales of the lateral-line scale row, and two rows of black spots scattered on the dorsal fin.

Two new species of shovel-jaw carp Onychostoma (Teleostei: Cyprinidae) from southern Vietnam

Two new species of large shovel-jaw carps in the genus Onychostoma are described from the upper Krong No and middle Dong Nai drainages of the Langbiang Plateau in southern Vietnam. These new species are known from streams in montane mixed pine and evergreen forests between 140 and 1112 m. Their populations are isolated in the headwaters of the upper Sre Pok River of the Mekong basin and in the middle of the Dong Nai basin. Both species are differentiated from their congeners by a combination of the following characters: transverse mouth opening width greater than head width, 14-17 predorsal scales, caudal-peduncle length 3.9-4.2 times in SL, no barbels in adults and juveniles, a strong serrated last simple ray of the dorsal fin, and small eye diameter (20.3-21.5% HL). Onychostoma krongnoensis sp. nov. is differentiated from Onychostoma dongnaiensis sp. nov. by body depth (4.0 vs. 3.2 times in SL), predorsal scale number (14-17 vs. 14-15), dorsal-fin length (4.5 vs. 4.2 times in SL), caudal-peduncle length (3.9 vs. 4.2 times in SL), colour in life (dark vs. bright), and by mitochondrial DNA (0.2% sequence divergence). Molecular evidence indicates that both species are members of Onychostoma and are distinct from all congeners sampled (uncorrected sequence divergences at the 16S rRNA gene of >2.0% for all Onychostoma for which homologous 16S rRNA sequences are available).

A review of the species of Oreichthys (Teleostei: Cyprinidae) in the Western Ghats, India

Fishes currently assigned to Oreichthys cosuatis from the Western Ghats are shown to belong to a closely-related group of three valid species: Puntius coorgensis, which is raised from synonymy, and two new species, O. duospilus and O. incognito. Oreichthys coorgensis can be distinguished from its congeners by a combination of characters that include 22-23+1-2 scales in the longitudinal series with 5-8 pored scales; ½3/1/2½ scales in the transverse row; 6-7 predorsal scales and usually a faint blackish spot on the caudal-fin base. Oreichthys duospilus, sp. nov., can be distinguished by possessing an almost complete lateral line with 11-21 pored scales and two black spots: one on the dorsal fin and the other on the anal fin. Oreichthys incognito, sp. nov., can be distinguished by a lateral line with 5 pored scales; ½3/1/1½ scales in the transverse row; 8 predorsal scales and a vertical black bar on the dorsal fin.

A new endemic species of Bryconamericus (Characiformes, Characidae) from the Middle Cauca River Basin, Colombia

Bryconamericus caldasi, a new species, is described from the Middle Cauca River drainage, Andean versant of Colombia. The new species is distinguished from all congeners by: the number of predorsal scales (15–17 vs. 9–14); a wide anterior maxilla tooth, at least twice as wide as the posterior tooth, both of which are pentacuspid (vs. maxilla teeth of same size); a dark lateral stripe overlaid by a peduncular spot; and a reticulated pattern on the sides of body (vs. peduncular spot and other body pigments not superimposed over a dark lateral stripe). We found several differences that distinguish the new species from B. caucanus, the only sympatric congener: number of predorsal median scales (15–17 vs. 12–13); convex predorsal profile (vs. oblique); scale size and number of scale rows at caudal–fin base (small scales arranged in two or more rows vs. large scales in just one row); pectoral fins not or just reaching pelvic fin insertions (vs. pectoral fins reaching posterior to pelvic–fin insertions); and dorsal–fin origin position (at vertical through posterior tip of pelvic–fin vs. at a vertical anterior to pelvic–fin tip).

A new species of fish belonging to of subgenus Spinibarbichthys (Spinibarbus: Cyprinidae: Cypriniformes) in Vietnam

Nine species of the genus Spinibarbus Oshima, 1919 (Cyprinidae, Cypriniformes) are found in Vietnam, of which one is new species of subgenus Spinibarbichthys; distributed in China, Laos and North of Vietnam. The description of the new species and a key to identify the known species of subgenus Spinibarbichthys of Spinibarbus genus are given in the paper. New species name: Spinibarbus (Spinibarbichthys) maensis H. D. Nguyen, Q. N. Duong & D. H. Tran sp. nov. Holotyp: one scantling (female) is found in Ma river (Camthuy district, Thanhhoa province) of Vietnam. Paratyp: one scantling is found in Nganpho river (Huongson district, Hatinh province) of Vietnam. Etymology: the name maensis refers to the locality of this species. Description: body high and thin. Head high and short. Mouth subanterior. Two pair of barbels. Gill rakers on first arch 10. Last dorsal simple ray osseous, with 19 pair serrae. Origin of dorsal fin behind of ventral fin and its origin near of origin of caudal fin than top of the nostril. Lateral line complete, pored scales in lateral series 27 - 28; Circumpeduncular scales 14, predorsal scales 8 + 5. Pharyngeal tooth three rows, 2.3.5-5.3.2. Coloration: body light roseate. Pectoral, ventral and anus fin are dark roseate. Distribution: lower and midle section of Ma and Nhatle rivers, Vietnam. Remarks: Spinibarbus (Spinibarbichthys) maensis sp. nov. is near with Spinibarbus (Spinibabichthys) denticulatus and Spinibarbus (Spinibarbichthys) namauensis by origin of dorsal fin behind of ventral fin. But there are some different characteristics: the number of lateral line scales are less, body is higher and thinner, head is higher in comparison with species Spinibarbus (Spinibarbichthys) denticulatus and Spinibarbus (Spinibarbichthys) namauensis. Spinibarbus (Spinibarbichthys) maensis differed with Spinibarbus (Spinibarbichthys) sinensis and Spinibarbus (Spinibarbichthys) ovalius by: origin of dorsal fin, number of gill ranker of first branchial, number of scales in front of dorsal fin, head is shorter and higher.

Redescription of Parapercis okamurai Kamohara, 1960 (Perciformes: Pinguipedidae), based on specimens newly collected from Taiwan and Japan.

A rare species of sandperch, Parapercis okamurai, is redescribed based on 2 types and 15 specimens newly collected from Taiwan and Japan. The species is unique in having cycloid scales on the parietal, opercle and subopercle, except for few large ctenoid scale that covers the base of the opercular spine; body color yellowish dorsally, with 10 or 11 faint yellow bands on lateral body and pale ventrally; and black spots on inner side of upper pectoral fin base. It can also be distinguished from congeners by having a combination of the following characters: dorsal-fin rays V, 23; anal-fin rays I, 19; pectoral-fin rays 18; pored lateral-line scales 59-64; medial predorsal scales 9-10; transverse scale rows 4.5-5.5/14-15; circumpeduncular scales 20-21; gill raker4-5+9-10=13-16; -4 pairs of canine teeth at front of lower jaw; 2-4 rows of teeth on vomer; 2 rows of teeth on palatines; scales on cheek moderately large, each half embedded; and body color yellowish dorsally and a prominent ocellus at upper caudal-fin base.

A New Species ofLeporinus(Characiformes: Anostomidae), from the Orinoco Basin, Venezuela

A new species of Leporinus in the L. cylindriformis group is described from the Río Orinoco basin, Venezuela. This new species can be separated from congeners by the combination of an extremely dorsoventrally slender body, the presence of a prominent midlateral spot positioned ventral to the dorsal fin, and the absence of any other intense dark pigmentation. The new species is most similar to L. aripuanaensis from the Rio Aripuanã, Brazil, but can be most easily differentiated from that species by the absence (79% of specimens) or faint presence (21% of specimens) of a circular dark spot over the hypural plate in the new species, versus the presence of an intensely pigmented dark spot in that position, respectively. It can be further distinguished from L. aripuanaensis by the modal number of predorsal scales (12 versus 11). Small juveniles of the two species do not differ morphometrically, but their allometric growth trajectories differ. Above 70 mm SL, the new species differs from L. aripuanaensis in interorbital width (34–44% HL versus 30–34%) and eye diameter (29–34% HL versus 26–30% HL). This new species represents the most recent of a long series of newly discovered taxa within Leporinus and reinforces the Orinoco Basin as a region of high endemism.

Psilorhynchus khopai, a new fish species (Teleostei: Psilorhynchidae) from Mizoram, northeastern India.

Psilorhynchus khopai, a new species of Psilorhynchidae, is described from Tuisi River, a tributary of Kaladan River, in Mizoram, India. The species is proposed to be a member of the Psilorhynchus homaloptera species group and can be distinguished from its congeners in having a forked caudal-fin with 9 + 9 principal caudal rays, 14-17 predorsal scale rows, 39-41 lateral-line scale rows, mid-lateral body with 9-12 indistinct small dark brown round markings forming a lateral stripe and, in life, a faint gold stripe along dorsal midline with 4-5 black spots between dorsal fin and caudal fin base.

Redescription ofCallogobius clarki(Goren) (Teleostei: Gobiidae), Not a Synonym ofC. bifasciatus(Smith)

Callogobius clarki (Goren) is redescribed based on 21 specimens from the Red Sea. This species was originally described from a single specimen collected from the Red Sea, but subsequent workers have placed it in synonymy with the Western Indian Ocean species C. bifasciatus (Smith). However, it differs from C. bifasciatus in lacking all head pores, and having a lower range in several meristic values (pectoral-fin rays usually 15–17 vs. 16–18, lateral scale rows usually 33–39 vs. 39–46, predorsal scale rows 12–15 vs. 16–20, transverse scale rows usually 17–18 vs. 18–22, and transverse mandibular papillae rows usually 11 vs. 12). Within the genus, C. clarki is a member of the sclateri group, exhibiting a female urogenital papilla with small distal flaps of skin, elongate ctenii on some caudal peduncle scales, and preopercular sensory papillae rows not continuous with the transverse opercular rows.

Oreichthys andrewi (Teleostei: Cyprinidae) a new species from Assam, northeastern India

Oreichthys cosuatis (Hamilton, 1822) was believed to be a monotypic genus widely distributed throughout India, Myanmar and ranging up to Thailand. Though the genus Oreichthys was known to have an incomplete lateral line, certain studies showed that there are species possessing a complete lateral line, as well as a much higher lateral line scale count. One such species is described here as a new species, Oreichthys andrewi, which can be distinguished from its congeners by the possession of a complete lateral line; 30+1 scales in the longitudinal series; ½ 4 / 1 / 2 ½ scales in the transverse row; 9 predorsal scales and bright yellow pelvic fins.

A NEW FRESHWATER GOBY OF Rhinogobius (TELEOSTEI: GOBIIDAE) FROM HAINAN ISLAND, SOUTHERN CHINA

A new freshwater goby of Rhinogobius Gill (1859) was collected from the Wangchuang River basin, Hainan Island, southern China. The new species, Rhinogobius sangenloensis, can be well distinguished from other congeners by a combination of the following features: second dorsal-fin rays modally I/8; anal-fin rays I/7-8; pectoral-fin rays modally 17; longitudinal scales 25-27; predorsal scales 9-11; vertebrae 26; body with 3-4 longitudinal, discontinuous orange to brown or brownish black bars and stripes; cheek with 2 grayish black spots in male; pectoral-fin base in male with 2 oblong black bars; caudal fin with an orange mark on lower 1/3 region in male. An artificial key to six species of Rhinogobius from Hainan Island is also provided.

A new species of the genus Pethia from Mizoram, northeastern India (Teleostei: Cyprinidae).

The paper describes Pethia expletiforis, a new cyprinid species from the Ka-ao River, Kaladan drainage, Mizoram, India. It is distinguished from its congeners in the Chindwin-Irrawaddy and Ganga-Brahmaputra drainages by the combination of: a complete lateral line, nine predorsal scales, 12 circumpeduncular scales, ½4/1/3½ transverse scales, a black blotch on the caudal peduncle, and the absence of a humeral mark and barbels.