Postorbital Length Research Articles

A new pearleye (Teleostei, Aulopiformes) species from the Oligocene of Romania

A new pearleye species of the alepisauroid family Scopelarchidae, Scopelarchoides neamticus sp. nov., is described herein based on two specimens from the Oligocene Lower Dysodilic Shales Formation, cropping out in the Pietricica Mountain, Romanian Eastern Carpathians. The new species described herein exhibits a unique combination of features (including head length about 25% of SL; coracoid remarkably expanded; both preorbital and postorbital lengths larger than orbit diameter; 50 or 51 vertebrae; dorsal fin with nine or ten rays; anal-fin with 28 rays; length of anal fin base about 30% of SL; preanal distance almost 60% of SL; pelvic fin insertion located just under the second dorsal fin ray; pectoral fins only slightly longer than pelvic fins; caudal fin with 19 principal rays plus 14 upper and 13 lower procurrent rays) that justifies its recognition as a new species of the genus Scopelarchoides. Both morphological and meristic features suggest a certain degree of similarity between S. neamticus sp. nov. and the extant species Scopelarchoides signifer. The fossils of the new Oligocene species described herein represent the oldest known skeletal record of Scopelarchidae.

Altigena malihkaia, a new species of Labeonini (Teleostei: Cyprinidae) from the Irrawaddy River basin in Myanmar.

Altigena malihkaia, new species, is described from the Mali Hka River, a tributary of the Irrawaddy River in northern Myanmar. It is distinguished from all other species of the genus Altigena by having a combination of 45-49 lateral-line scales, 12-14 circumpeduncular scales, 17-20 pre-dorsal midline scales, wide head (96.8-138.5% HL), long postorbital length (64.6-81.0 % HL), and short dorsal-fin (length 21.9-26.2% SL).

A New Species of Mullet Chelon caeruleum (Family: Mugilidae) with Description of its Genetic Relationship to Some Mugilids

Abstract Chelon caeruleum sp. nov. is described as a new species of Chelon encountered in the Rashid coastal region of the Mediterranean Sea, Egypt. With this finding, the new species is the sixth member of the genus Chelon. Chelon caeruleum sp. nov. is distinguished from its congeners by the following characters: colouration of body is dark bluish grey dorsally and the sides are blue; head length 20.5 to 21.6% SL; head width 13 to 13.5% SL; pre-first dorsal fin length 50% SL; eye diameter 4.6 to 5.2% SL; postorbital length 10.7 to 11.1% SL; unbranched pyloric caeca are 2 short and 4 long; a pair of long (one longer than the other), spine-like neural postzygapophyse on the second vertebra. DNA of Chelon caeruleum sp. nov. and five mullet species (Mugil cephalus, Liza carinata, Liza ramada, Liza aurata, and Chelon labrosus) was extracted then amplified using polymerase chain reaction (PCR) and sequenced. The mtDNA cytochrome oxidase subunit I sequence analysis confirmed that Chelon caeruleum sp. nov. is distinct from other congeners of Chelon and it is a different species of Chelon which is new to science.

A new species of Hypopygus Hoedeman (Gymnotiformes: Rhamphichthyidae) from the rio Trombetas system, Amazon basin, Brazil.

A new Hypopygus species is described from the igarapé Saracá, a stream in the lower rio Trombetas system, Pará State, Brazil. It differs from congeners by a unique combination of characters (either primitive or of uncertain polarity) which includes mouth position, interocular width, snout length, postorbital length, pectoral-fin length, snout-to-occiput length, caudal-filament length, counts of pectoral-fin rays and anal-fin rays, distribution of anal-fin chomatophores, as well as a set of osteological features. A phylogenetic analysis indicates that the new species, belongs to a monophyletic subgroup in Hypopygus that includes all congeners, except H. neblinae; its relationships within that clade, however, are currently uncertain, and a brief discussion is provided. Corrections are made concerning some morphometric and meristic information furnished in recent contributions regarding Hypopygus species.

HEMIBRYCON GUEJARENSIS, A NEW SPECIES FROM THE GÜEJAR RIVER, ORINOCO BASIN, COLOMBIA (CHARACIFORMES: CHARACIDAE) WITH A REVIEW THE POPULATIONS IDENTIFIED AS HEMIBRYCON METAE

Hemibrycon guejarensis, new species, is described from the Güejar River, La Macarena mountain range, upper Guaviare River drainage, Colombia. The new species is distinguished from most cis-Andean congeners (H. jabonero Lake Maracaibo and adjacent Caribbean drainages, H. metae which is found in the Guavio River, some Orinoco and Caribbean River drainages in Venezuela, and H. taeniurus from Trinidad and adjacent mainland drainages in Venezuela) in having ii, 7, i dorsal-fin rays (vs. ii, 8). H. guejarensis is further distinguished from H. taeniurus and H. jabonero, in having a wider second pigment layer in the humeral spot (covering 3 vs. 2 scale widths). H. guejarensis is very similar to H. metae (an allopatric species also present in streams of the Orinoco River Basin in Venezuela and Colombia and some Venezuelan Caribbean drainages). Hemibrycon guejarensis is distinguishedby the orientation of the dorsal lateral-line canal which crosses the ventral part of the humeral spot transversely vs. horizontally across dorsal part of spot in the holotype of H. metae and Orinoco and Caribbean populations. H. guejarensis differs from H. metae in having the tip of the pectoral fin passing the pelvic-fin insertions (vs. pectoral fin tip not reaching pelvic-fin insertions). We identify populations previously considered as Hemibrycon metae from Venezuelan Orinoco River Basin piedmont streams and Caribbean drainages to be instead H. jabonero and H. taeniurus. Careful analysis of these populations indicated that all of them differ from the H. metae holotype and topotypic specimens in pelvic fin and postorbital lengths.

Sexual dimorphism in black jaw tiliapia (Sarotherodon melanotheron) and banded jewelfish (Hemichromis fasciatus) from the Great Kwa River, Calabar, Nigeria

AbstractIn this study, the pattern and magnitude of sexual dimorphic differences have been investigated in black jaw tilapia (Sarotherodon melanotheron) (n = 160; 74 males and 86 females) and banded jewelfish (Hemichromis fasciatus) (n = 120; 42 males and 78 females) from the Great Kwa River, Calabar, Nigeria. Fish samples were collected between July and December 2015. Fourteen morphometric variables, including body weight, total length, standard length, body depth, cheek depth, pre-orbital length, postorbital length, pectoral fin length (right and left), pelvic fin length (right and left), head length, gonad weight, eye diameter and four meristic variables, including number of pectoral fins (right and left) and number of pelvic fins (right and left), were taken using standard methods. Size-adjusted morphometric measurements subjected to step-wise discriminant function analysis were used to determine predictor variables to morphologically differentiate sexes for both species; magnitude of dimorphism between sexes was estimated using percentage classification accuracy of the discriminant function analysis. From the discriminant function analysis, the pectoral fin length and gonad weight positively contributed significantly to morphometric dimorphism (magnitude=69.2%) in male and femaleS. melanotheronsuggesting adaptation for reproductive function; while forH. fasciatusthe body depth and standard length were important contributors to sexual dimorphism (magnitude=84.2%) suggesting size dimorphism for aggressiveness, territorial behavior and improving swimming performance. Overall, our results indicate that the different magnitude of sexual dimorphism between the two species could be attributable to the type and functional role of sexual dimorphic traits.

A new species of the deepwater scorpionfish genus Phenacoscorpius (Teleostei: Scorpaenidae) from the Galápagos Islands

A new species of scorpionfish, Phenacoscorpius mccoskeri, is described based on three specimens from the Galápagos Islands, Ecuador, eastern Pacific. The new species is distinguished from other species of Phenacoscorpius by the following combination of characters: 19–20 pectoral-fin rays, middle rays branched; 5–19 pored lateral-line scales; palatine teeth present; small slit behind fourth gill arch; second preopercular spine absent; and nuchal and parietal spines distinct; in addition to some morphometric characters, including head length and width, interorbital width, caudal-peduncle depth and postorbital length.

A Quick View on Biology of Near Threatened Peacock Eel (<i>Macrognathus aculeatus</i>) in Khulna Region of Bangladesh

The Peacock eel, Macrognathus aculeatus is a near threatened highly valuable small indigenous species in Bangladesh. It is not only toothsome nutritive table fish but also notable aquarium species but still rely on natural stock. Keeping in mind the paucity of information on the biology which is crucial to develop artificial propagation and culture technique of this species, the present research was performed as an attempt to contribute to the information on the taxonomy and other biological aspects of M. aculeatus. Total 50 samples were collected from Khulna region during April to May 2014 to assay. The taxonomical study revealed that the total length, standard length, head length, eye diameter, pre and post orbital length; length of dorsal, anal and caudal fin; length of upper and lower jaw; body depth and width, distance between dorsal fin to caudal fin ranged from 17.00-21.00, 15.00-19.00, 0.80-3.00, 0.20-0.40, 0.50-2.10, 0.30-1.70, 3.10-6.70, 3.50-6.30, 0.50-1.50, 0.30-1.00, 0.70-1.80, 0.90-2.30, 0.60-1.20, 0.70-2.40 cm respectively, additionally meristic character’s formula appeared like D. 19 - 39, A. 11 - 18, C. 29 – 52, L. 11-15 and number of eye spots on dorsal fin, 3-10. Turning to the biological inquiry which showed that the fish weight (g), gonad weight (g), liver weight (g), gut weight (g), gonadosomatic, alimentosomatic and hepatosomatic index and condition factor ranged from 15.10-28.60, 2.32-3.18, 0.029-0.044, 0.64-1.08, 9.69-14.79, 2.58-4.15, 0.11-0.19 and 0.30-0.40 respectably. The mean values of hepatosomatic and alimentosomatic indices persuaded greater liver activity and feeding intensity in M. aculeatus. Moreover, stomach content depicted that the diet of peacock eel composed of small fish species, small prawn, prawn larvae, earthworm, water strider, insects pupae, Metaphire posthuma, Caenorhabditis, sand and mud for instance, which in brief expressed that M. aculeatus is omnivorous in its feeding habits. Indeed, this preliminary research outcome would be utile for the species identification, seed production, developing culture technologies as well as biodiversity conservation of this near threatened fish species.

Landmark-based Morphometric and Meristic Variations of Endangered Mrigal Carp, Cirrhinus cirrhosus (Bloch 1795), from Wild and Hatchery Stocks

Wild stocks of endangered mrigal carp, Cirrhinus cirrhosus (Bloch 1795), continues to decline rapidly in the Indo-Ganges river basin. With an objective to evaluate its population status, landmark-based morphometric and meristic variations among three different stocks viz., hatchery (Jessore), baor (Gopalganj) and river (Faridpur) in Bangladesh were studied. Significant differences were observed in 10 of the 15 morphometric measurements viz., head length, standard length, fork length, length of base of spinous, pre-orbital length, eye length, post-orbital length, length of upper jaw, height of pelvic fin and barbel length, two of the 8 meristic counts viz., scales above the lateral line and pectoral fin rays and 10 of the 22 truss network measurements viz., 1 to 10, 2 to 3, 2 to 8, 2 to 9, 2 to 10, 3 to 4, 3 to 8, 4 to 5, 4 to 7 and 9 to 10 among the stocks. For morphometric and landmark measurements, the 1st discriminant function (DF) accounted for 58.1% and the 2nd DF accounted for 41.9% of the among-group variability. In discriminant space, the river stock was isolated from the other two stocks. On the other hand, baor and hatchery stocks formed a very compact cluster. A dendrogram based on the hierarchical cluster analysis using morphometric and truss distance data placed the hatchery and baor in one cluster and the river in another cluster and the distance between the river and hatchery populations was the highest. Morphological differences among stocks are expected, because of their geographical isolation and their origin from different ancestors. The baseline information derived from the present study would be useful for genetic studies and in the assessment of environmental impacts on C. cirrhosus populations in Bangladesh.

Review of the genus Banjos (Perciformes: Banjosidae) with descriptions of two new species and a new subspecies

A taxonomic review of the genus Banjos (Perciformes: Banjosidae), previously restricted to a single species, Banjos banjos (Richardson 1846), recorded from the northwestern Pacific Ocean from the South China Sea north to Japan, as well as Lombok (Indonesia), New Caledonia and Australia, resulted in the recognition of three species, including B. banjos (northwestern Pacific Ocean, Indonesia and western Australia), Banjos aculeatus sp. nov. (eastern Australia) and Banjos peregrinus sp. nov. [northern Australia (Timor Sea)]. Records of B. banjos from New Caledonia probably also represent B. aculeatus, which is clearly distinct from other congeners in having a relatively long, strongly serrated spine at the posteroventral angle of the preopercle and an entirely dusky membrane on the spinous dorsal fin in juveniles < ca. 70 mm SL, in addition to slightly longer first and second dorsal-fin spines. Banjos peregrinus is characterized by a relatively greater head length, orbit diameter, postorbital length and pre-pelvic-fin length, as well as poorly developed serration of the exposed margin of the cleithrum. Within B. banjos, a population from the southeastern Indian Ocean, including Indonesia and western Australia, is regarded as a distinct subspecies (Banjos banjos brevispinis ssp. nov.), distinguishable from B. b. banjos from the northwestern Pacific Ocean by a relatively narrow least interorbital width, and shorter second and eighth dorsal-fin spines. Ontogenetic morphological changes within the genus and the status of the holotype of Anoplus banjos Richardson 1846 are discussed in detail.

Ocorrência do Camarão Tigre-Gigante Penaeus monodon Fabricius, 1798 (Crustacea, Decapoda, Penaeidae) na Plataforma Continental Piauiense

This study aimed to report the first occurrence of giant asian tiger shrimp Penaeus monodon Fabricius, 1798 in Piaui coast. A unique example was captured in March 2015 by a shrimp fishing boat. In the laboratory the specimen was identified, sexed, weighed and measured in carapace length (CL), post-orbital length (POL) and length (TL). The exemplary captured it is a female with 298.45 g, 316.20 mm (TL), 133.85 mm (CL) and 90.10 mm (POL) and was found in the depth range of 4 to 6 meters in latitude: 02°50'51.1S and longitude: 041°40'03.9W. Keywords: Bioinvasion; Penaeus monodom ; Piaui Continental Shelf.

Morphometric differentiation between two juvenile tuna species [Thunnus thynnus (Linnaeus, 1758) and Euthynnus alletteratus (Rafinesque, 1810)] from the Eastern Mediterranean Sea

The main objective of this study was to analyse the differences in morphometric characteristics among specimens of Atlantic juvenile bluefin tuna Thunnus thynnus [12.2–46.5 cm fork length (FL)] and juvenile little tuna Euthynnus alletteratus (14.1–26.4 cm FL). A total of 353 bluefin tuna (young of the year) and 288 little tuna (young of the year) were collected from the commercial hand line fisheries in the eastern Mediterranean Sea between July and October of 2011–2013 with three round-bent hook sizes (numbers 10, 12 and 14; Mustad 2315S). By using univariate and multivariate analysis, 11 morphometric characters were investigated. anova revealed highly significant differences (P < 0.001) for all morphometric parameters among the two species. The principal component analysis showed that the difference between the species resulted mainly from preanal length (LA), caudal fin hight (CC), snout length (SnL), eye diameter (ED) and postorbital length (PO). The stepwise discriminant analysis revealed that juveniles of the two tuna species were correctly classified, with a percentage of 99.2%. Length of pectoral fin (LP) was the strongest predictor in the discriminant functions.

Size structure, sex ratio and weight-length relationships of the sailfish Istiophorus platypterus from Mazatlan, sinaloa, Mexico.

We describe the size frequency distribution, sex ratio and weight-length relationship of the IndoPacific sailfish Istiophorus platypterus off the coast of Mazatlan, Sinaloa, Gulf of California. Data were collected from the sports fishery during several sampling periods from 2002 to 2009. A total of 354 Sailfish were sampled, including 185 females, 161 males and 8 of unknown sex. Total weight (TW) varied from 14 to 41 kg, and sizesranged between 128 and 195 cm postorbital length (PL), with significant differences between the sexes (P &lt; 0.05). The sex ratio throughout the period analyzed was 0.87: 1 (M:H). The total length (TL) and postorbital length (LPO) of organisms were related through the linear fit model for both sexes TL = 57.204 + 1.15 x LPO (r2 = 0.65). There were no significant differences in the weight-length relationship between the sexes (ANCOVA, P&gt;0.05).The general equation relating weight and length for both sexes was TW = 0.0009 x PL2.009. The value of the slope b was significantly different from 3, indicating negative allometric growth (t, P &lt; 0.05). Indo-Pacific sailfish exploitation is currently limited to the sports-recreational fishery; however, there are initiatives to promote the commercial exploitation of this resource. Therefore, results derived from this study are of importance, since they providebasic information on the biology of this species, and can serve as a baseline for the management of this resource.

Review of the scorpionfish genus Pteroidichthys (Scorpaenidae), with descriptions of two new species.

A taxonomic review of the scorpaenid genus Pteroidichthys Bleeker, 1856 resulted in recognizing four valid species, including two new species; P. acutus n. sp., P. amboinensis Bleeker 1856, P. caussei n. sp., and P. noronhai (Fowler 1938). The genus Pteropelor Fowler, 1938 is regarded as a junior synonym of Pteroidichthys. Rhinopias godfreyi Whitley 1954, previously treated as a valid species, is herein regarded as a junior synonym of P. amboinensis. Pteroidichthys amboinensis and P. caussei have two spines and six soft rays in the anal fin and a supplemental preopercular spine, whereas P. acutus and P. noronhai have three spines and five rays, and lack the spine. Pteroidichthys amboinensis differs from P. caussei in having flexible dorsal-fin spines (vs. rigid in the latter) and tentacles on the supraocular and posterior lacrimal spines well developed, their lengths greater than the orbit diameter (vs. less than orbit diameter). Pteroidichthys noronhai differs from P. acutus in having a relatively short snout, its length shorter than (vs. longer than in the latter) the postorbital length, and a distance between tips of the lateral lacrimal and first suborbital spines shorter than or subequal to (vs. longer than) that between tips of the first and second suborbital spines. Pteroidichthys acutus is known from the western Pacific in depths of 73-400 m, P. amboinensis from the Indo-West Pacific in 7-43 m, P. caussei from the South Pacific in 68-122 m, and P. noronhai from the western Pacific and Western Australia in 52-215 m.

A new species of scorpionfish, Ebosia vespertina (Scorpaenidae: Pteroinae), from the southwestern Indian Ocean

A new species of scorpaenid fish, Ebosia vespertina sp. nov., is described on the basis of 19 specimens from off Mozambique, South Africa, and Madagascar, southwestern Indian Ocean. The new species is most similar to Ebosia falcata and Ebosia saya, known from the northern and eastern Indian Ocean and Saya de Malha Bank, respectively, in having usually 8 anal-fin soft rays, usually more than 17 pectoral-fin rays, and the elongated parietal spine in males narrow and strongly curved posterodorsally. However, E. vespertina can be distinguished from the two latter species by the following combination of characters: pectoral-fin rays 17–18 (modally 18); scale rows above the lateral line 4–6 (5); scale rows between the last dorsal-fin spine base and lateral line 4–5 (5); scale rows between the sixth dorsal-fin spine base and lateral line 4–5 (5); postorbital length 17.4–20.3 (mean 18.7) % of standard length (SL); longest pectoral-fin ray length 54.6–73.9 (65.1) % of SL; longest pelvic-fin soft ray length 32.4–44.0 (37.6) % of SL. The remaining congener, Ebosia bleekeri, known from the western Pacific Ocean, usually has 7 anal-fin soft rays and 16 pectoral-fin rays, and the elongated parietal spine in males relatively broad and not so strongly curved.

Pterois paucispinula, a new species of lionfish (Scorpaenidae: Pteroinae) from the western Pacific Ocean

A new species of lionfish (Scorpaenidae: Pteroinae), Pterois paucispinula sp. nov., is described on the basis of 37 specimens from the western Pacific Ocean. The new species is closely related to and has been previously confused with Pterois mombasae (Smith 1957), both species sharing usually XIII, 10 dorsal-fin rays, usually more than 18 pectoral-fin rays, numerous black blotches on the pectoral-fin membrane, and several bands on the posterior portion of the pectoral-fin rays (free from membrane). However, P. paucispinula differs from similarly sized P. mombasae in having a lesser body depth at the anal-fin origin, head width, postorbital length, and caudal-peduncle depth, in addition to a slightly higher number of scale rows below the lateral line. Pterois paucispinula also differs from the typical form of P. mombasae, occurring off the east coast of Africa and in the central Indian Ocean and Andaman Sea, by having usually 18 pectoral-fin rays (vs. usually 19 in the latter) and relatively long dorsal-fin spines, with the longest dorsal-fin spine length 42.9–51.7 % of standard length (SL) (vs. 35.1–44.8 % of SL). Although a Sri Lankan population of P. mombasae is similar to P. paucispinula in the above characters (usually 18 pectoral-fin rays and longest dorsal-fin spine length 37.5–51.1 % of SL), such differences among P. mombasae are regarded as intra-specific geographical variations. Additionally, young and adult P. mombasae have ctenoid scales on the pectoral-fin base, ventrolateral portion of the body (below the lateral line) and laterally on the caudal peduncle. These regions in all examined P. paucispinula usually have only cycloid or at most a few ctenoid scales, thereby providing a consistent basis for identification of both species, including the Sri Lankan population of P. mombasae. Pterois mombasae is distributed in the Indian Ocean from the east coast of Africa to the Andaman Sea, whereas P. paucispinula is recorded from the western Pacific Ocean, from northern Australia to southern Japan and eastward to the Wallis and Futuna Islands.

A new species of scorpionfish, Ebosia saya (Scorpaenidae: Pteroinae), from the western Indian Ocean and notes on fresh coloration of Ebosia falcata

A new scorpionfish, Ebosia saya sp. nov. (Scorpaenidae: Pteroinae), is described on the basis of 10 specimens collected from the Saya de Malha Bank in depths of 95–126 m. Comparisons with two valid Indo-Pacific species, Ebosiableekeri (Doderlein in Steindachner and Doderlein 1884) (western Pacific Ocean) and Ebosiafalcata Eschmeyer and Rama-Rao 1978 (northern and eastern Indian Ocean), showed E. saya to be most similar to the latter, with both species sharing 8 (usually) anal-fin soft rays, 17 (usually) pectoral-fin rays, the elongated parietal spine of males relatively narrow and strongly falcate posterodorsally, and the pectoral fin predominantly yellow in males, whereas E. bleekeri has 7 (usually) anal-fin soft rays, 16 (usually) pectoral-fin rays, the elongated parietal spine of males relatively broad and weakly falcate, and the pectoral fins entirely red in males. However, E. saya differs from E. falcata in having 5 scale rows above the lateral line [vs. 4 or 5 (modally 4) in E. falcata], slightly greater total numbers (5–20, mean 12.3) of preocular, supraocular, and postocular spines at 60–90 mm SL (vs. 4–18, 8.4), shorter postorbital length 18.1–19.2 (mean 18.7) % SL [vs. 19.8–23.5 (21.5) % SL], and the blotch above the pectoral-fin base and blotches on the pectoral-fin membrane all relatively smaller. Fresh coloration of E. falcata is described for the first time, based on specimens from the Andaman Sea (easternmost record for the species).

Morphological and molecular evidence of three species of pikes Esox spp. (Actinopterygii, Esocidae) in France, including the description of a new species

This integrative taxonomy study of French pikes compares morphological characters and molecular sequence data (mitochondrial COI and nuclear Plagl2 genes). In addition to the expected E. lucius, DNA sequences and morphology both support a new species in France, E. aquitanicus sp. nov. from the Charente to the Adour drainages. It is characterized by a color pattern of sides with narrow 1–1.5-scale-wide oblique vertical bands, conferring it a marbled coat, a snout only 0.9 times larger than the postorbital length, an anal fin basis 1.1–1.2 times larger than the caudal peduncle length, 101 to 121 lateral scales, 53 to 57 vertebrae, as well as 24 diagnostic sites in the COI gene and 3 in the Plagl2 gene. Partial COI sequences (131bp) from modern and historical specimens indicate also the presence of E. cisalpinus and E. lucius during the 19th century in Lake Geneva. Morphological and molecular data points to a possible hybridization between E. lucius with both other local pike species, representing a risk for them. Their endangerment status should be evaluated rapidly in order to take conservation measures.

Fluctuating asymmetry in grass goby Zosterisessor ophiocephalus Pallas, 1811 inhabiting polluted and unpolluted area in Tunisia

Fluctuating asymmetry, a random deviation of bilateral traits, is assessed on grass goby Zosterisessor ophiocephalus Pallas, 1811 living in one disturbed site and in one unpolluted site Gulf of Gabes (Tunisia). Statistical analysis showed that assessed asymmetries are fluctuating. FA of orbital diameter, sub-orbital distance, pectoral fin and post-orbital length are higher in polluted site compared to control. Chemical pollution seems to be responsible for this high FA.

Variation in morphometric and meristic traits of Aspidoparia morar from Brahmaputra and Barak Rivers of Assam, India

The minor carp, Aspidoparia morar is a benthopelagic fish belonging to the sub-family Danioninae under the family Cyprinidae. It has emerged as the single most dominant species in the river Brahmaputra in Assam. In the present study, 240 specimens were collected from Guwahati and Tezpur in the Brahmaputra River and Silchar in the Barak River to investigate the morphometric and meristic variation among the populations. For this a total of 20 morphometric traits and 11 meristic traits were studied. The mean lengths for most of the morphometric traits were higher for the Barak River except eye diameter, inter orbital length and anal fin length which were significantly higher on the Brahmaputra River, while the post orbital length and pelvic fin length were found to be almost equal. The regressions of standard length with all the morphometric traits except pelvic fin length, pelvic fin base, pectoral fin length, dorsal fin length, anal fin length, pre orbital length, post orbital length, inter orbital length and eye diameter showed significant variation between the rivers. Two meristic traits viz. branched rays in anal fin and gill rakers on the first gill arch also showed significant variation in the samples of the rivers.