Predorsal Area Research Articles

Two new species of freshwater goby (Teleostei, Gobiidae) from the Upper Youshui River, Chongqing, China.

Two previously unknown species of Rhinogobius have been discovered in the streams of the Upper Youshui River, within the Yuan River Basin, Xiushan County, Chongqing, China. These new species are named as Rhinogobiussudoccidentalis and Rhinogobiuslithopolychroma. Phylogenetic analysis based on mitochondrial genomes revealed that R.sudoccidentalis is genetically closest to R.reticulatus, while R.lithopolychroma shares the greatest genetic similarity with R.leavelli. Morphological distinctions allow for the clear differentiation of these species. Rhinogobiussudoccidentalis sp. nov. is characterized by having VI-VII rays in the first dorsal fin and I, 8-9 rays in the second dorsal fin. The longitudinal scale series typically consists of 22-24 scales, while the transverse scale series comprises 7-8 scales. Notably, the predorsal scale series is absent and the total vertebrae count is 12+17=29. Rhinogobiuslithopolychroma sp. nov. can be distinguished from other species by the presence of 13-15 rays on the pectoral fin. Its longitudinal scale series ranges from 30 to 33 scales, with no scales in the predorsal area. The total vertebral count is 30, with 12 precaudal and 18 caudal vertebrae. The head and body of this species are light gray with irregular orange markings on the cheeks and opercle. Through morphological and molecular analyses, it has been confirmed that R.lithopolychroma and R.sudoccidentalis represent novel species within the Rhinogobius genus.

Acanthopagrus oconnorae, a new species of seabream (Sparidae) from the Red Sea.

A new species of sparid fish, Acanthopagrus oconnorae, is described based on 11 specimens collected in the shallow (0-1m depth) mangrove-adjacent sandflats of Thuwal, Saudi Arabia. The new species is distinguished from its congeners by the following combination of characters: second anal-fin spine 12.8%-16.6% of standard length (SL); 3½ scale rows between the fifth dorsal-fin spine and lateral line; suborbital width 5.7%-6.7% of SL; eyes positioned at the anterior edge of the head, often forming a weakly convex break in an otherwise gently curved head profile, when viewed laterally; caudal fin light yellow with black posterior margin (approximately half of fin); anal fin dusky grey, with posterior one-fifth of the fin light yellow; black streaks on inter-radial membranes of anal fin absent. The most similar species to A. oconnorae is Acanthopagrus vagus, which differs by the presence of a w-shaped anterior edge of the scaled predorsal area, a more acute snout and black streaks on the inter-radial membranes of the anal fin. Phylogenetic placement and species delimitation of A. oconnorae are discussed based on COI, CytB and 16S sequences. It is hypothesized that ecology and behaviour explain how this species avoided detection despite its likely occurrence in coastal areas of the Red Sea with historically high fishing pressure.

Lebetus patzneri (Teleostei: Gobiidae), a new goby species from the Balearic Islands, western Mediterranean, with first records of Lebetus guilleti (Le Danois, 1913) from this area and Norway, and with notes on its biology.

A new goby species, Lebetus patzneri sp. nov. (Teleostei: Gobiidae) is described based on two preserved and two photographed specimens collected from two circalittoral bottom locations off the Balearic Islands, western Mediterranean. It differs from the one or both other Lebetus species by each of following characters: P 15-16; D2 segmented fin rays 7-8; snout slightly larger than eye diameter; eyes small, 23.3-25.5% of head length; body height low, body depth at pelvic fin 14.9-16.4%; lips thick, giving mouth a broad, almost rectangular shape in dorsal and lateral view; minute black "pepper" spots on predorsal area, dorsum, flanks and caudal peduncle, visible in fresh and preserved specimens; the most of the caudal peduncle similarly colored as the lateral area below D2, reddish or brown. We further report first records of Lebetus guilleti (Le Danois, 1913) from Norway and the Balearic Islands, and observations of its conspicuous courtship behavior ("D1 waving"), and coloration including the first description of its red fluorescence pattern.

Two new deep-water species of the genus Thorogobius (Teleostei: Gobiidae) from the upper continental slope of the Eastern Central Atlantic.

Two new gobiid species, Thorogobius alvheimi sp. nov. and Thorogobius laureatus sp. nov. (Teleostei: Gobiiformes: Gobiidae), are described from the outer continental shelf and upper slope of the Eastern Central Atlantic off Angola, Ghana and São Tomé and Príncipe. The specimens were trawled from depths between 57 and 208m. The new species are most similar to Thorogobius angolensis. Thorogobius alvheimi sp. nov. is distinguished from its congeners in the combination of following characters. Fins: first dorsal fin with the second and third spines distinctly elongated; pectoral fin ray count 20-21; pelvic disc complete and short with well-developed anterior membrane (frenum) and pointed lateral lobes. Scales: nape and predorsal area naked; no scales on opercle; scales in longitudinal series 27-31. Pattern of free neuromasts: supratemporal rows tr and trp developed, extending transversally between pores H and K; longitudinal row g short, not passing row m posteriorly and distinctly distant from row h; infraorbital row 6 long, ventrally extending to lower margin of preopercle, its ventral section 6i originating anterior to its dorsal section 6s; posterior lateral row h reaching anteriorly above posterior third of opercle. Coloration: body uniformly pale fawn and brown; margin of scale pockets dark brown pigmented, yielding a reticulated pattern; pale spots on nape and predorsal area; caudal fin uniformly dusky greyish. Thorogobius laureatus sp. nov. is distinguished from its congeners in the combination of following characters. Fins: first dorsal fin the second and third spines distinctly elongated; pectoral fin ray count 19-22; pelvic disc complete, short, with well-developed anterior membrane (frenum) with pointed lateral lobes. Scales: scales on sides of predorsal area and midline mostly naked; no scales on opercle; scales in longitudinal series 24-27. Pattern of free neuromasts (sensory papillae): supratemporal rows tr and trp developed, extending transversally between pores H and K; longitudinal row g long, passing row m posteriorly and relatively close to row h; infraorbital row 6 long, ventrally extending to lower margin of preopercle, its ventral (6i) and dorsal (6s) originating opposite to each other; posterior lateral rows: row h long, reaching anteriorly above middle of opercle. Coloration: body pale fawn and brownish; margin of scale pockets dark brown pigmented, yielding a reticulated pattern; five brown blotches on flanks in lateral midline from below first dorsal fin to caudal peduncle; caudal fin with six or seven distinct dark vertical bands.

A new species of Pomatoschistus (Teleostei, Gobiidae): the Mediterranean's smallest marine fish

The new sand goby species Pomatoschistus nanus (Teleostei: Gobiidae) is described from the northern coast of the Levantine Sea (eastern Mediterranean Sea) based on both morphological and DNA barcoding data. The new species is the smallest fish in the Mediterranean Sea and may be distinguished from congeners by the following features: predorsal area, first dorsal-fin base and breast naked; δ-pore missing; anterior point of the suborbital row b not reaching level of posterior point of suborbital row d; slightly emarginated caudal fin and nape coloration pattern. DNA barcode data clearly discriminate Pomatoschistus spp. in the neighbour-joining tree with an average of 17·7% interspecific K2P distance. The most closely related taxon to P. nanus sp. nov. is Pomatoschistus bathi and the most distantly related is Pomatoschistus tortonesei with 11·9 and 21·9% K2P distances respectively. Morphometric and genetic data are also provided for Pomatoschistus bathi.

Schistura epixenos, a new species of loach from the Nakai Plateau, Laos (Teleostei: Nemacheilidae)

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.

A new Schistura from the Pearl River in Guangxi, China (Teleostei: Nemacheilidae).

Schistura paraxena, new species, is described from the Pearl River drainage in Laibin, Guangxi Province, China. The new species is easily distinguished from its congeners in having conspicuous peduncular crests along its dorsal and ventral extremities and a plain beige body coloration with crests brownish gray and a pale spot medially at caudal-fin base. Further characters useful to diagnose the species, but not unique to it, are: 8½ branched dorsal-fin rays; 11-12 pectoral-fin and 9 pelvic-fin rays; modally 38 vertebrae; predorsal length 50-52% SL; caudal-peduncle length 17-18% SL (88-92% HL; 5.6-5.8 times SL); lateral line complete; breast naked; predorsal area scaled; and upper lip not notched.

Reconciling more than 150 years of taxonomic confusion:the true identity of Moenkhausia lepidura, witha key to the species of theM. lepiduragroup (Characiformes: Characidae).

Moenkhausia lepidura (Kner) is redescribed based on the examination of the type and other specimens from several localities of the Amazon and Orinoco basins. The species is readly diagnosed from congeners by a combination of a dark blotch on the upper caudal-fin lobe, lower lobe hyaline, and by the arrangement of predorsal scales, in which scales of anterior portion of predorsal area are arranged in pairs, followed by a single median row of scales extending to dorsal-fin origin. The analysis of the type material of Gymnotichthys hildae Fernández-Yépez and Knodus calliurus Ahl demonstrated the former is a junior synonym of Moenkhausia lepidura, whereas the latter should be removed from its synonymy. An identification key to the Moenkhausia lepidura-group is provided.

Ponticola iranicus sp. nov. (Actinopterygii: Perciformes: Gobiidae) from the Caspian Sea basin

Background. Five species of Ponticola have hitherto been recognized among freshwater gobies in the Ponto–Caspian basin. In 2014 a number of specimens representing this genus were collected in northern Iran. The detailed morphological and karyological study of those gobies collected revealed significant differences between them and their known congeners. The aim of this study was to describe these fish as a new species from the Caspian Sea basin. Materials and methods. The fish specimens were collected in August 2014 at two localities of the Sefid-Rud River drainage, and in the Gisum River, Guilan Province, northern Iran. In total, 18 specimens were used for karyological study following a previously described method. Both karyotyped and intact specimens were then morphologically investigated using characters developed for study on gobiids, and particular for freshwater Caucasian gobies. The comparative materials were specimens from museum collections, as well as published descriptions, illustrations, and measurements of other species. Results. Ponticola iranicus sp. nov. differs from its congeners in a set of the following features: D1 VI, D2 I/(14½) 15½ – 17½, A I/10½ – 13½; nape scaled completely, scales cycloid; cycloid scales covering upper part of opercle; lateral line system with posterior sub-orbital row d2 continuous; predorsal area uniform, dark grey; first dorsal fin with oblique black stripe between first two or three rays; short dark grey strip on upper part of pectoral fin base; karyotype consisting of 46 acrocentric chromosomes. Conclusion. All known  Ponto–Caspian gobies demonstrate mosaic pattern of morphological and karyological features that presumes their polyphyletic origins. Further phylogenetic studies by molecular genetic methods are necessary for identification of their marine ancestors and clarifying of common trends in the evolution of the Ponto–Caspian goby group.

Ponticola iranicus sp. nov. (Actinopterygii: Perciformes: Gobiidae) from the Caspian Sea basin

Background. Five species of Ponticola have hitherto been recognized among freshwater gobies in the Ponto–Caspian basin. In 2014 a number of specimens representing this genus were collected in northern Iran. The detailed morphological and karyological study of those gobies collected revealed significant differences between them and their known congeners. The aim of this study was to describe these fish as a new species from the Caspian Sea basin. Materials and methods. The fish specimens were collected in August 2014 at two localities of the Sefid-Rud River drainage, and in the Gisum River, Guilan Province, northern Iran. In total, 18 specimens were used for karyological study following a previously described method. Both karyotyped and intact specimens were then morphologically investigated using characters developed for study on gobiids, and particular for freshwater Caucasian gobies. The comparative materials were specimens from museum collections, as well as published descriptions, illustrations, and measurements of other species. Results. Ponticola iranicus sp. nov. differs from its congeners in a set of the following features: D1 VI, D2 I/(14½) 15½ – 17½, A I/10½ – 13½; nape scaled completely, scales cycloid; cycloid scales covering upper part of opercle; lateral line system with posterior sub-orbital row d2 continuous; predorsal area uniform, dark grey; first dorsal fin with oblique black stripe between first two or three rays; short dark grey strip on upper part of pectoral fin base; karyotype consisting of 46 acrocentric chromosomes. Conclusion. All known  Ponto–Caspian gobies demonstrate mosaic pattern of morphological and karyological features that presumes their polyphyletic origins. Further phylogenetic studies by molecular genetic methods are necessary for identification of their marine ancestors and clarifying of common trends in the evolution of the Ponto–Caspian goby group.

Two new species of Cabillus (Perciformes: Gobiidae) and the first record of Cabillus macrophthalmus from the Western Indian Ocean.

Two new species of the gobiid genus Cabillus, C. nigromarginatus sp. nov. and Cabillus nigrostigmus sp. nov. are described. Cabillus nigromarginatus (from Rodrigues, Western Indian Ocean) is distinguished from congeners by having 18-20 pectoral-fin rays; predorsal area naked; two scales with enlarged ctenii ventrally and dorsally at the caudal-fin base; head with anterior and posterior oculoscapular, and preopercular canals, with pores σ, λ, κ, ω, α, β, ρ, ρ1, ρ2 and γ, δ, ε respectively; the body with four midline lateral blotches, with two or three of them expanding upwards in dorsal saddles; a dark triangular blotch at caudal-fin base; and predorsal with pigmentation at lateral edges forming a rectangle. Cabillus nigrostigmus (from the Red Sea) is distinguished from its congeners by having 19 pectoral-fin rays; transverse scale series 7; nape scaled, median predorsal scales 7; body depth 5.8-6.0 in SL; snout length 1.5-1.9 in eye diameter; caudal-peduncle depth in its length 2.4-2.5; a broad dark brown bar below first dorsal fin beginning anteriorly at the level of fourth spine of the first dorsal fin; elongate black blotch along posterior half of first dorsal fin extending into the sixth spine and adjacent membranes; and midlateral black spot at the end of caudal peduncle followed by S-shaped dark bar. Cabillus macrophthalmus is recorded for the first time in the Western Indian Ocean (Red Sea and Seychelles) and redescribed.

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 Pachycara (Teleostei: Zoarcidae) from the Sub-Antarctic Southern Indian Ocean, and a Range Extension of Lycenchelys Antarctica

During the multidisciplinary benthic Crozet research cruise (RRS Discovery, D300), December 2005 to January 2006, in the abyssal vicinity of the Crozet Islands, southern Indian Ocean, two new species of Pachycara were collected, along with specimens of Lycenchelys antarctica. Pachycara priedei, new species, and P. cousinsi, new species, described herein are similar in lack of pelvic fin, naked abdomen and predorsal area, and number of head pores. They differ from their congeners by the pink coloration and long predorsal distance, respectively. The records of L. antarctica extend the range of the species about 60° to the east, into the southern Indian Ocean.

New Species of Shallow Water Scorpionfish (Scorpaenidae: Scorpaena) from the Central Coast of Western Australia

A new species of scorpionfish, Scorpaena gasta, is described on the basis of five specimens collected from the warm temperate central coast of Western Australia, eastern Indian Ocean, at depths of 3–7 m. Scorpaena gasta is most similar to a Western Australian species, S. sumptuosa. The two species are distinguished from other IndoPacific species of Scorpaena by the following combination of characters: lateral surface of maxilla with a distinct longitudinal ridge; relatively thick skin with numerous small sensory pores covering nearly the entire predorsal area to near the first pored lateralline scale; anteroventral surface of lower jaw with one or two pairs of slender tentacles in ventral view. Scorpaena gasta and S. sumptuosa are separated by four meristic, several morphometric, and color features. Scorpaena gasta is a small species (smallest mature female 67.4 mm SL; largest known specimen 83.6 mm SL), whereas S. sumptuosa is a relatively large species, attaining at least 241 mm SL.

Three new Australian species of the fish genus Xenisthmus (Gobioidei: Xenisthmidae)

Xenisthmus chi n.sp., described from two specimens from Rowley Shoals, Timor Sea, has in combination: second dorsal-fin rays I,12; anal-fin rays I,11; predorsal area with narrow median wedge of scales extending forward almost to pore D; posterior naris without flap; and head and body pale with brown reticulate mottling, forming about 11 X-shaped markings along sides between pectoral- and caudal-fin bases. Xenisthmus eirospilus n.sp., described from 15 specimens from throughout the southwest Pacific (type locality Elizabeth Reef, Tasman Sea), has in combination: second dorsal-fin rays I,12-13, usually I,12; anal-fin rays I,11-12, usually I,11; vertebrae 10 + 17; tongue indented; posterior naris with well-developed flap; upper sides of body with 12 large closely spaced spots, which usually do not extend to dorsal edge of body; and predorsal scaled to vertical through posterior edge of preopercle. Xenisthmus semicinctus n.sp., described from two specimens from Rowley Shoals, Timor Sea, has in combination: second dorsal-fin rays I,12; anal-fin rays I,11; vertebrae 10 + 17; tongue indented; posterior naris with well-developed flap; upper sides of body with 12 large, closely spaced spots, each connecting dorsally to, or almost to, mid-line by short, dark bar; and predorsal area with narrow median wedge of scales extending forward almost to pore D.

A new species of the neotropical annual fish genus Pterolebias (Cyprinodontiformes, Rivulidae), from Central Brazil

A new species of Pterolebias from Caceres, Paraguay River Basin, State of Mato Grosso, Brazil, is described. It was found in a temporary lagoon on the Brazilian Central Cerrado and seems to have the same annual habits of the other species of the group. The new species differs from all other species but P. staeckiin the colour pattern on the sides of the body, which consists of longitudinal stripes. From P. siaecki it differs in the relative length of the pelvic‐fin and of the predorsal area and by the number of scales in the longitudinal series. The similarity between P. bokermanni and P. longipinnis is discussed.

Sistemática del género Cheirodon (Pisces: Characidae) en Chile con descriptión de una nueva especie. análisis de Multivarianza.

Abstract Systematics of the genus Cheirodon (Pisces: Characidae) in Chile with description of a new species. Multivariance analysis. Five species of the genus Cheirodon (Characidae) are described for Chile: Ch. pisciculus Girard, Ch. Galusdae Eigenmann, Ch. australe Eigenmann, Ch. intermptus interruptus (Jenyns), and Ch. kiliani nov. sp. Ch. kiliani is described as a new species based on the combination of patterns it presents on tricuspid teeth, the predorsal area is half naked of scales and the ventral procurrent rays of the caudal fin occupy almost half of caudal peduncle. Ch. i. interruptus is considered as an introduced species to Chile from Argentina. For each species, 21 morphometric and 12 meristic characters were considered for the analysis of Numerical Taxonomy and the Principal Component programs. The dendrogram groups the following species in one set: Ch. kiliani, Ch. pisciculus, Ch. galusdae and another with Ch. i. interruptus, Ch. australe. The species appear very similar in the cluster anal...