Maxillary Barbel Length Research Articles

New species of Batrochoglanis Gill (Siluriformes: Pseudopimelodidae) from the Capim River basin, State of Pará, Brazil

Batrochoglanis labrosus new species, is described from the Capim River Basin, State of Pará, Brazil. The new species differs from congeners by the stout, inferior mandible, hypertrophied lips on the lateral of the mouth, a broad dark brown band extending dorsoventrally from the beginning of the trunk to the posterior third of the adipose fin followed by a second dark brown band on the caudal peduncle, dark brown pelvic fin, and caudal fin hyaline with a concentration of dark brown spots on the posterior margin, sometimes forming an irregular band. The morphometric variables of B. labrosus are similar in B. villosus and B. castaneus, forming a B. villosus species group. The B. villosus group is distinct from other group formed by B. acanthochiroides and B. transmontanus in the third axis of the Principal Components Analysis. The variables with higher positive loadings in the B. villosus group, representing larger measurements, were adipose-fin base length, eye diameter, maxillary barbel length, head depth, and mouth width; the higher negative loadings representing shorter measurements were pelvic fin to anal fin distance and pectoral-fin spine length. The species is known only from the Capim River basin, where it is possibly endemic.

Balitora anlongensis, the first cavefish species of the genus Balitora (Teleostei, Balitoridae) from Guizhou Province, southwest China

This work describes a new species, Balitora anlongensissp. nov., collected from a cave at Xinglong Town, Anlong County, Guzihou, China. Phylogenetic trees reconstructed based on two mitochondrial and three nuclear genes show that the new species represents an independent evolutionary lineage with large genetic differences, 7.1%–12.0% in mitochondrial gene cytochrome b and 9.2%–12.1% in cytochrome oxidase subunit 1, from congeners. Morphologically, the new species can be distinguished from the 18 species currently assigned to the genus Balitora by a combination of characters, most clearly by having two pairs of maxillary barbels; 8½ branched dorsal-fin rays; 5½ branched anal-fin rays; pectoral fin not reaching pelvic fin origin; dorsal-fin origin in front of pelvic fin origin; eye small (eye diameter approximately equal to outer maxillary barbel length); and fins lacking pigment in live fish. The new species represents the first record of Balitora inhabiting caves in China and increases the number of species in the genus Balitora in its present concept from 18 to 19. The study suggests that more evidence is needed to further clarify the taxonomic composition of the genus Balitora.

Exostoma dhritiae, a new sisorid catfish (Teleostei: Sisoridae) from the Brahmaputra River drainage, Arunachal Pradesh, India

A new species of sisorid catfish of the genusExostomais described from the Siang River in Arunachal Pradesh, northeastern India. The new species,Exostoma dhritiae, can be distinguished from congeners by the condition of the posterior extremity of the adipose-fin base, the degree of tuberculation on the dorsal surface of the head, and the shape of striae on the anterolateral surface of lips. Further, it is distinguished by the morphometric data for the body depth at the anus, maxillary barbel length, adipose fin base length, caudal peduncle length, caudal peduncle depth and the number of branched pectoral-fin rays. It is the twentieth reported species of Exostoma.

‘Henicorhynchus’ thaitui, a new species of cavefish from Central Vietnam (Teleostei, Cyprinidae)

‘Henicorhynchus’thaituisp. nov. is described from a subterranean stream in a karst cave in Phong Nha Ke Bang National Park, Quang Binh Province, Central Vietnam. It differs from all congeners in having a pale pink body in life, smaller eyes with diameter less than the maxillary barbel length, and two pairs of barbels, the maxillary barbel being much longer than the rostral barbel.

Onychostoma brevibarba, a new cyprinine fish (Pisces: Teleostei) from the middle Chang Jiang basin in Hunan Province, South China.

Onychostoma brevibarba, a new cyprinid species, is described from two tributaries flowing into the Xiang Jiang (= River) of the middle Chang Jiang basin in Hunan Province, South China. The new species is morphologically similar to two Chinese congeners, O. minnanense and O. barbatulum, but differs from them in the anteromedian extension of the postlabial groove. It further differs from O. minnanense in the maxillary-barbel length, shape and body coloration, and from O. barbatulum in the number of lateral-line perforated scales and the width of the mouth opening. The validity of the new species and its close relationship with these two species were affirmed by a molecular phylogenetic analysis based on the mitochondrial cyt b and CO1 genes.

Reappraisal of Rhamdia branneri Haseman, 1911 and R. voulezi Haseman, 1911 (Siluriformes: Heptapteridae) from the rio Iguaçu with notes on their morphometry and karyotype

ABSTRACT The species Rhamdia branneri Haseman, 1911 and the subspecies Rhamdia branneri voulezi Haseman, 1911 from rio Iguaçu are currently recognized as synonyms of Rhamdia quelen (Quoy & Gaimard, 1824). However, recent karyotype and ecomorphology studies distinguish R. branneri and R. voulezi as different species. Examination of Rhamdia populations from rio Iguaçu, including type specimens, together with other congeners from rio Tibagi, allowed to properly reexamine the situation of these Haseman's taxa and references given to Rhamdia in the Iguaçu. The species R. branneri and R. voulezi have strong serrae with large basis on both margins of the pectoral-fin spine, uncommon in the remaining species of Rhamdia and different from the fine serrate margins of the pectoral spine of R. quelen ; a regular dorsal profile, slightly curved between supraoccipital and dorsal fin; with dorsal dark-brown or light-gray coloration along body, abdomen pale, without profuse small black spots, common in populations of the upper Paraná species and the type-material of R. quelen . Also the following morphometric characters discriminate these species: Rhamdia voulezi , adipose fin elongate; smaller distance between dorsal and adipose fin; smaller length between adipose fin to base of caudal fin and smaller distance from posterior margin of eye to opercular border. Rhamdia branneri , larger distance from dorsal and adipose fins; deeper caudal peduncle; higher trunk depth in the vertical distance through adipose, between pelvic and anal fins; larger scapular bridge; shorter maxillary barbel; shorter external mental barbel; shorter interorbital distance; shorter length of dorsal fin basis and shorter adipose-fin base length. A PCA between the populations of Rhamdia from Iguaçu and a population from rio Tibagi, upper Paraná basin, discriminates the population from Tibagi on basis of dorsal to adipose fin distance, dorsal-fin spine length, maxillary barbel length, eye diameter, and pectoral-fin spine length. This morphometric study allied to the karyotype known differences suggest R. branneri and R. voulezi as valid species. The complex state of R. quelen with the neotype recently designated from rio Samiria recommend new studies on basis of molecular genetics and provision of the names R. branneri and R. voulezi in the Iguaçu basin.

A new cavefish species from Southwest China, Sinocyclocheilus gracilicaudatus sp. nov. (Teleostei: Cypriniformes: Cyprinidae).

One new species is added to the genus Sinocyclocheilus, the largest cyprinid genus in China and the largest cavefish genus in the world. Sinocyclocheilus gracilicaudatus sp. nov. is similar to S. donglanensis but differs to other congeners in having normal eyes and scaled body, curved lateral line with 59-64 lateral-line scale rows, half-hard dorsal fin spine, 8 gill rakers and 8 predorsal vertebrae. Compared to S. donglanensis, the new species has a longer and more narrow caudal peduncle (caudal peduncle length 21.3-22.7% vs. 16.8-20.4% of SL; caudal peduncle depth 10.5-12.0% vs. 12.5-15.5% of SL), smaller eyes (eye diameter 5.8-8.3% vs. 6.5-10.9% of SL) and longer barbels (maxillary barbel length 16.6-24.3% vs. 11.1-21.1 % of SL; rictal barbel length 19.5-21.6% vs. 11.3-21.1% of SL). The new species is distributed in a subterranean river, belonging to the Longjiang River system; S. donglanensis occurs in the Hongshuihe River system, a system separate from that where the former species occurs.

Redescription of the Striped Catfish Mystus tengara (Hamilton, 1822) (Siluriformes: Bagridae), India

The Bagrid Catfish Mystus tengara was described from a pond located in India under the genus Pimelodus. The validity of the fish has been confused and has frequently been treated as a synonym of Mystus vittatus. In this study, the species is rediagnosed and redescribed on the basis of fresh material collected from the Ganga-Brahmaputra drainage. M. tengara is diagnosed from congeners in having a unique combination of the following characters: body with a distinct tympanic spot and four brown stripes which are separated by a pale narrow interspace; origin of adipose-fin not reaching the base of the last dorsal-fin ray, 31-42 gill rakers on first branchial arch, eye rounded with a diameter 19.0-23.8 % HL and dorsal spine length 12.3-17.2 % SL, maxillary barbel length 254.5-360.5 % HL. A key for the identification of Mystus species from Ganga-Bramaputra drainage is also provided.

Growth and morphological development of laboratory-reared larval and juvenile bighead catfish Clarias macrocephalus (Siluriformes: Clariidae)

Morphological development in laboratory-reared larval and juvenile bighead catfish Clarias macrocephalus is described. Body length (BL) of larvae and juveniles was 3.4 ± 0.3 (mean ± SD) mm just after hatching, reaching 11.3 ± 1.0 mm by day 16, and 24.2 ± 2.8 mm by day 40. Overall aggregate fin ray numbers (except for caudal fin procurrent rays) attained full complements by 15.2 mm BL. Gill buds appeared on day 0, those of barbels (four pairs) and primordial nostrils on day 1, and pectoral fins on day 3. All larvae began feeding by day 3. Conical teeth were observed on day 7. Notochord flexion began on day 2, the yolk being completely absorbed during days 7–9. Melanophores were scarce at hatching, increasing with growth to cover almost the entire body except the ventral surface of the abdominal cavity. Proportions of head length, pre-anal length, body depth, eye diameter, and maxillary barbel length became relatively constant after yolk absorption, those of snout length and upper jaw length increasing until ca. 12–13 mm BL and decreasing thereafter. Suprabranchial organ started developing in postflexion larval stage larger than ca. 11.0 mm BL (day 16), and air-breathing was suggested to be functional at that time.

Growth and morphological development of laboratory-reared larval and juvenile Hemibagrus filamentus (Siluriformes: Bagridae)

Morphological development in laboratory-reared larval and juvenile Hemibagrus filamentus, and behavioral features observed under rearing conditions are described. Body lengths (BL) of larvae and juveniles were 3.8 ± 0.2 (mean ± SD) mm just after hatching and 11.7 ± 1.6 mm on day 15, reaching 26.5 ± 5.4 mm on day 30 after hatching. Aggregate fin ray numbers (for caudal fin, except for procurrent rays) attained full complements in specimens larger than 12.9 mm BL. A maxillary barbel bud appeared on day 0, and all larvae initiated feeding on day 3 with the development of mandibular barbels and conical teeth. Pectoral fin buds and primordial nostrils were present on day 1. Notochord flexion began on day 3, and the yolk was completely absorbed by day 4. Melanophores were scarce at hatching, but increased with growth to cover almost the entire body except the ventral surface of the head and body. Body proportions became relatively constant in juveniles, excepting maxillary barbel length that continued to increase, reaching over 40% BL. Fish were negatively phototactic from day 1. Cannibalism was observed from day 6, continuing to the juvenile stage.

Growth and morphological development of laboratory-reared larval and juvenile Pangasianodon hypophthalmus

The morphological development, including the fins, body proportions and pigmentation, of laboratory-reared larval and juvenile Pangasianodon hypophthalmus was described and their behavioral features were observed under rearing conditions. Body lengths (BL) of larvae and juveniles were 3.0 ± 0.2 (mean ± SD) mm just after hatching, and 12.9 ± 1.1 mm on day 13, reaching 23.4 ± 1.8 mm on day 25 after hatching. Aggregate fin ray numbers (for caudal fin, principal soft ray number) attained their full complements in specimens larger than 12.8 mm BL. Notochord flexion began in yolksac larvae on day 0 (10.5 h after hatching), with teeth buds and barbels appearing with jaw formation in yolksac flexion larvae on day 1. Melanophores on the body increased with growth, with a broad vertical band forming on the lateral line and an oblique band extending from above the pectoral fin base towards the forepart of the anal fin during the postflexion larval and juvenile stages. Body proportions became relatively constant in juveniles, except for maxillary barbel length (MBL), which continued to decrease. Yolksac flexion larvae started feeding on day 2 with the onset of intense cannibalism. Yolks were completely absorbed by day 3, and cannibalism ended by day 6. Subsequently, fish displayed a schooling behavior with growth, preferring relatively dark areas during the juvenile stage.

The identity of Schizothorax griseus Pellegrin, 1931, with descriptions of three new species of schizothoracine fishes (Teleostei: Cyprinidae) from China

The identity of Schizothorax griseus Pellegrin, 1931, is clarified and the species redescribed. Three new species previously identified as S. griseus are described: S. nudiventris, from the Lancang Jiang, China; S. heterophysallidos, from the Nanpan Jiang, China; and S. beipanensis, from the upper Beipan Jiang, China. The group comprising Schizothorax griseus, S. nudiventris, S. heterophysallidos and S. beipanensis can be diagnosed from other members of this genus by the absence of an obvious horny sheath on the lower jaw; lower lip developed with three labial lobes in mature individuals; postlabial groove continuous, with a small labial lobe present in the middle of the lower lip; last unbranched dorsal-fin ray strong, its posterior edge with numerous serrae; and scales absent on ventral surface between pectoral fins in adults (except in S. griseus). Schizothorax griseus differs from S. nudiventris, S. heterophysallidos and S. beipanensis by the presence (vs. absence) of concealed scales in the skin on the ventral surface between the pectoral fins in adults; the presence (vs. absence) of a shallow ethmoidal groove before the nostrils; and having barbels much longer than eye diameter (eye diameter 33.4–93.7 % (vs. 57.2–160.0) of maxillary-barbel length). Schizothorax nudiventris is distinguished from S. heterophysallidos and S. beipanensis in having only the proximal ¾ (vs. entirety) of the last unbranched dorsal-fin ray strong; pelvic-fin origin opposite or posterior (vs. opposite or anterior) to vertical through dorsal-fin origin; and irregular black spots present (vs. absent) on side of body. Schizothorax heterophysallidos is distinguished from S. griseus, S. nudiventris and S. beipanensis in having a larger posterior chamber of the air bladder (vs. posterior chamber as large as, or slightly larger than, anterior one), length of posterior chamber 3–6 (vs. 2) times length of anterior chamber. Schizothorax beipanensis is distinguished from S. griseus by the absence (vs. presence) of scales on the thorax in mature individuals; absence (vs. presence) of black spots on side of body; and having the maxillary barbel 58.5–120.1 % SL (vs. 33.4–93.7 % SL).

Akysis portellus sp. nov., a new species of catfish (Teleostei: Akysidae) from the Sittang River drainage, Myanmar

A second species of akysid catfish from the Sittang River drainage in Myanmar, Akysis portellus new species, is described in this study. It can be distinguished from congeners (except for A. brachybarbatus, A. fuliginatus, A. manipurensis, A. pictus, A. pulvinatus, A. prashadi, A. variegatus, A. varius, A. vespa and A. vespertinus) in having a smooth (vs. serrated) posterior edge of the pectoral spine. It is distinguished from A. brachybarbatus, A. fuliginatus, A. manipurensis, A. pictus, A. prashadi, A. pulvinatus, A. variegatus, A. varius, A. vespa and A. vespertinus in having a unique combination of: length of adipose-fin base 17.1-19.2% SL, caudal peduncle length 19.1-22.0% SL, caudal peduncle depth 6.0-7.0% SL, gape width 9.5-11.1% HL, interorbital distance 30.8-36.8% HL, nasal barbel length 80.5-101.4% HL, maxillary barbel length 116.7-143.2% HL, inner mandibular barbel length 53.7-79.2% HL, outer mandibular barbel length 101.1-127.8% HL and caudal fin forked.

Taxonomic Status and Redescription of the Gillbacker Sea Catfish (Siluriformes: Ariidae: Sciades parkeri)

The Gillbacker Sea Catfish is a valid species of ariid catfish from the northeastern coast of South America. There are many synonyms in the literature for the Gillbacker Sea Catfish and even recent classifications have used different scientific names. Examination of a wide range of sizes of individuals from different localities and examination of types and original species descriptions of Silurus parkeri, Bagrus flavescens, B. emphysetus, Arius physacanthus, A. bonneti, A. clavispinosus, and A. despaxi has lead us to the conclusion that all these names refer to the Gillbacker Sea Catfish and the valid name for the species is Sciades parkeri. The species is distinguished from all other ariid species by the following combination of features: body coloration yellow; swim bladder divided into three chambers, posterior chamber moderately sized; nuchal plate shield-shaped, usually larger than supraocciptal process; anterior notch of nuchal plate absent; head shield exposed and granulated in orbital and postorbital regions; lateral edge of accessory patches not emarginated or shallowly notched; fleshy furrow connecting posterior nares absent; and mesial gill rakers absent from first two gill arches. Striking intraspecific and/or ontogenetic variation in eye size, maxillary-barbel length, supraoccipital-process size, nuchal-plate size and shape, and dorsal-spine thickness contributed to the numerous synonyms and misidentifications for Sciades parkeri. Bagrus albicans, described from French Guiana, has at times been listed as a synonym of Sciades parkeri. Our examination of the holotype of B. albicans, however, led us to conclude that it is a synonym of Sciades proops.

Mayr\'s coefficient of difference and taxonomy of clarias (clariidae – scopoli, 1777)

Coefficient of difference in 54 morphometric characters was studied using 258 Clarias species from Anambra river, Nigeria. There were no differences between C. ebrensis andC. albopunctatus for all the 54 characters studied. The coefficient of difference in morphometric characters of C. ebriensis vs. C.gariepinus indicated that about 90 % of C. ebriensis were significantly different from about 90 % of C. gariepinus in about 34 morphometric characters. Thirty seven differentiating morphometric characters occurred between C. ebriensis and C. anguillaris. Considering the discrimnating characters between C. albopunctatus and C. gariepinus, 90 % of C. abopunctatus differed from 90% of C. gariepinus in about 32 characters. Furthermore, about 90 % of C. albopunctatus differed from 90 % of C. anguillaris in about 35 characters. Differentiating of C. gariepinus from C. anguillaris based on the coefficient of difference was impossibe for all the 54 characters studied. The coefficients of difference among all clariids studied were almost identical in 10 characters namely: maximum body depth, pectoral spine height, anal fin base length, inner mandibular barbe length, outer mandibular barbel length, maxillary barbel length, premaxillary teeth band depth, vomerine teeth band depth, prenasal length and nasal - nasal barbel space, with exception of C. ebriensis vs. C. albopunctatus and C. gariepinus vs. C. anguillaris. These characters thus represent “key characters” for differentiating between the “small” and “large” clariids. Keywords: Mayr's Coefficient of Difference, Clarias, Clariidae, Taxonomy Animal Research International Vol. 1 (1) 2004: pp. 36-41

Akysis longifilis, a new species of catfish (Teleostei: Akysidae) from Myanmar

Akysis longifilis, new species, is described from the Sittang River drainage in Myanmar. It is a member of the A. variegatus species group and can be distinguished from congeners in the group (except for A. brachybarbatus, A. fuliginatus, A. pictus, A. prashadi, A. variegatus, A. varius and A. vespa) in having a smooth (vs. serrated) posterior edge of the pectoral spine. It is distinguished from A. brachybarbatus, A. fuliginatus, A. pictus, A. prashadi, A. variegatus, A. varius and A. vespa in having a unique combination of: length of adipose-fin base 25.7–31.1% SL, body depth at anus 9.7–13.6% SL, caudal peduncle length 18.3–23.2% SL, caudal peduncle depth 5.6–7.2% SL, head width 21.1–24.7% SL, nasal barbel length 67.4–96.4% HL, maxillary barbel length 123.2–159.6% HL, vertebrae 33–35, body with light saddle-shaped spots, and caudal fin forked.

A new species of Microglanis (Siluriformes: Pseudopimelodidae) from the rio Uruguay drainage, Brazil

A new pseudopimelodid catfish, Microglanis malabarbai, is described from the rio Ijuí drainage, tributary of the middle rio Uruguay, Rio Grande do Sul, Brazil. The new species is distinguished from all other Microglanis species by the caudal fin color pattern, almost completely black, with a narrow vertical white band across central portions of the caudal-fin rays. Furthermore, it is distinguished from M. cottoides and M. eurystoma, both from rio Uruguay drainage, by head length, maxillary barbel length, internareal distance, and number of lateral-line pores, and from M. cibelae from the coastal drainages of northern Rio Grande do Sul and southern Santa Catarina states, by head length, maxillary barbel length, and body width. A key is presented for the species of Microglanis occurring in southern Brazil.