Caudal Peduncle Length Research Articles

Morphological differences between an artificial lentic and adjacent lotic environments in a characid species

Dam constructions cause fundamental changes in the natural landscape, creating new ecological and evolutionary challenges for aquatic organisms. In some cases, such water impoundments have been related with morphological changes in organisms. Understanding how populations respond to rapid environmental changes imposed by dams is the first step to elucidate the consequences that disturbed habitats may have on species evolution. In this work, we analyzed shape and size variation in Bryconamericus iheringii Boulenger 1887 from the Chasqueiro stream basin, south of Brazil, which was recently dammed. We used linear measurements and geometric morphometrics to identify morphological differences among specimens from the reservoir (lentic habitat) compared to the habitat upstream and downstream of the dam (lotic habitats). We also tested for size- and shape-related sexual dimorphism to determine whether variations observed were the same for both sexes. We found that B. iheringii from the artificial reservoir were distinct in shape and size to those from their natural habitat in the stream. The size variation between environments was the same for both sexes, but the shape variation differed between males and females. Regarding the linear measurements, lotic populations were larger (greater body length, width, pectoral fin base length and caudal peduncle length), probably in response to increased swimming activity. Regarding body shape, we found that both sexes have a more fusiform body in lotic habitats than in the reservoir. In addition, females showed an altered mouth position that was distinct between these environments. This work indicates that the water reservoir seems to be an important factor influencing morphological variation in B. iheringii, a species with sexual shape dimorphism.

Phenotypic Characteristics of the Clupeid Fish Tenualosa ilisha (Family: Clupeidae) collected from Manjhand Vicinity, Pakistan

Thirteen body proportions of the clupeid species, Tenualosailisha were investigated from Manjhand locality on the Indus River, Pakistan. Negative allometricgrowths for all morphometric traits examined were attained. The highest value of ‘b’ coefficient obtained was at its highest level for fork length (0.8834) and its lowest value for eye diameter (0.0398). The correlation coefficient value (R2) was at its lowest value for the relationship of the pectoral fin length-total fish length (0.46), the medium value of 0.77 and 0.80 were obtained for dorsal fin base length and anal fin base length respectively, while the highest value of 0.99 was attained for the relationship of both fork and standard lengths-total length and 0.98 for caudal peduncle length followed by 0.94 for the relationship of postorbital length-total fish length. The present report provides data to fishery biologists on body proportions of T. ilisha from the Indus River valley, Pakistan to support in development of management policies for this fish species.

Morphometric and meristic study of four freshwater fish species of river Ganga

The present study was carried out in Ganga River from Devprayag to Haridwar district of Uttarakhand to analyse morphometric measurement and meristic count of some selected fish species during April 2017 to March 2018. Specimens (20) of each fish species were collected from different zones of river Ganga and 24 morphometric measurements and eight meristic count parameters were studied for each fish species. The total length and weight of Cyprnius carpio ranged from 14–18 cm and 60–78 g; Mahseer fish species 21–28 cm and 120–185 g; 20–26 cm and 100–160 g (Labeo rohita) and 17–25 cm and 20–34 g (Xenentodon cancila) respectively were recorded during the study period. The regression coefficient ‘b’ shows higher growth rate with respect to Total length. It was maximum in case of standard length (b= 1.115) and lowest in pelvic fin length (b=0.146) for Cyprnius carpio, maximum in case of standard length (b=1.132) and lowest in pectoral fin length (b=0.126) for Mahseer, maximum in case of Fork and standard length (b=0.995) and lowest in length of caudal peduncle (b=0.135) for Labeo rohita and maximum in case of standard length (b=1.020) and lowest in case of pelvic fin length (b=0.018) for Xenentodon cancila respectively.

Exostoma kottelati, a new species of catfish (Teleostei: Sisoridae) from Arunachal Pradesh, India.

Exostoma kottelati, new species, is described from the Ranga River, Brahmaputra basin, in Arunachal Pradesh state, northeastern India. It differs from congeners in the Brahmaputra River basin in having a longer adipose-fin base (33.4-36.0 % SL vs. 23.4-32.9), a greater (except E. mangdechhuensis) pre-pelvic length (45.6-47.3 % SL vs. 39.3-44.6) and a greater pre-anal length (73.9-76.5 % SL vs. 62.2-70.1). It further differs from all known congeners by the following unique combination characters: the adipose fin is distinctly separated from the dorsal procurrent caudal-fin rays, pre-dorsal length 38.9-41.7% SL, adipose-fin base length 33.4-36 % SL, caudal peduncle length 18.7-21.1 % SL, caudal peduncle depth 8.8-9.5 % SL, and body depth at anus 12.5-13.5 % SL. This is the fifth species of Exostoma known from the Brahmaputra River basin.

Discriminating Sex in Zebrafish (Danio rerio) Using Geometric Morphometrics.

Zebrafish (Danio rerio) adults are viewed as sexually dimorphic. However, current approaches to sex discrimination rely mainly on subjective assessment of color patterns and body structures. Here, we explore how geometric morphometrics allow for quantitative sex discrimination based on overall body geometry of adult zebrafish (aged 12-24 months). Ten homologous landmarks were placed on the left lateral view of adult zebrafish and transformed through Procrustes superimposition before being analyzed with canonical variate analysis. We compared two models to distinguish between sexes. The first model consisted of landmarks that included the abdominal region and the second model did not. Males and females clearly diverged along a single canonical variate, and jackknife testing reinforced the strength of the sorting algorithm with 100% correct assignment of sex for both models. Analysis of body geometry demonstrated that males have a longer caudal peduncle, a more streamlined ventral region, and slightly more inferior placement of eyes than females. Based on these results we developed a logistic regression equation using the ratio of ventral caudal peduncle length to standard length to provide researchers a reliable and objective method for sex discrimination in zebrafish.

Review and re-description of Sabanejewia species in Iran (Teleostei: Cobitidae)

The Iranian species of the genus Sabanejewia are reviewed based on morphological, osteological and molecular characters of the mtDNA COI barcode region. Two species, Sabanejewia aurata and Sabanejewia caspia are recognized and diagnoses are presented for both species. They are distinguishable through body pattern, length of caudal peduncle, snout and post orbital distance, shape of scale and suborbital spine, caudal complex skeleton and also the number of fixed, diagnostic nucleotide substitutions. Here we re-describe both Iranian spined loaches.

Morphological comparison of western and eastern populations of Caspian kutum, Rutilus kutum (Kamensky, 1901) (Cyprinidae) in the southern Caspian Sea

This study aimed to investigate morphological differences of western and eastern populations of Caspian kutum Rutilus kutum in the southern Caspian Sea and its providing length-weight relationships and condition factor (CF). A 13-landmark based morphometric truss network system was used to investigate the hypothesis of population fragmentation of western and eastern populations of this species. The studied populations were differentmorphologically based on pre anal, body height, distance from pectoral fin to ventral fin, distance from pectoral fin to anal fin, caudal peduncle length, head length, pre orbital, pre ventral, and dorsal length. The results also revealed a negative allometry (b<3) of length-weight relationships for both sexes. Maximum condition factors was found in March. The results suggest distinct stocks in the western and eastern of Caspian Sea for fisheries management.

Discovery and validation of candidate smoltification gene expression biomarkers across multiple species and ecotypes of Pacific salmonids.

Early marine survival of juvenile salmon is intimately associated with their physiological condition during smoltification and ocean entry. Smoltification (parr–smolt transformation) is a developmental process that allows salmon to acquire seawater tolerance in preparation for marine living. Traditionally, this developmental process has been monitored using gill Na+/K+-ATPase (NKA) activity or plasma hormones, but gill gene expression offers the possibility of another method. Here, we describe the discovery of candidate genes from gill tissue for staging smoltification using comparisons of microarray studies with particular focus on the commonalities between anadromous Rainbow trout and Sockeye salmon datasets, as well as a literature comparison encompassing more species. A subset of 37 candidate genes mainly from the microarray analyses was used for TaqMan quantitative PCR assay design and their expression patterns were validated using gill samples from four groups, representing three species and two ecotypes: Coho salmon, Sockeye salmon, stream-type Chinook salmon and ocean-type Chinook salmon. The best smoltification biomarkers, as measured by consistent changes across these four groups, were genes involved in ion regulation, oxygen transport and immunity. Smoltification gene expression patterns (using the top 10 biomarkers) were confirmed by significant correlations with NKA activity and were associated with changes in body brightness, caudal fin darkness and caudal peduncle length. We incorporate gene expression patterns of pre-smolt, smolt and de-smolt trials from acute seawater transfers from a companion study to develop a preliminary seawater tolerance classification model for ocean-type Chinook salmon. This work demonstrates the potential of gene expression biomarkers to stage smoltification and classify juveniles as pre-smolt, smolt or de-smolt.

A new species of Yunnanilus (Cypriniformes: Nemacheilidae) from Sichuan, southwest China.

A new species of Yunnanilus is described from Tuojiang River, Sichuan, China. The new species, Yunnanilus jiuchiensis, can be distinguished from other species of Yunnanilus by the following combination of characters: processus dentiformis absent; body covered with scarce scales; lateral-line incomplete, as long as half the length of the pectoral-fin length, with 6-11 pores; eye diameter larger than interorbital width; and caudal-peduncle length less than its depth.

A New Species ofCurculionichthys(Siluriformes: Hypoptopomatinae) from the Western Border of the Brazilian Shield, Madeira River Basin, Brazil

Curculionichthys scaius, new species, is distinguished from other congeners by having two usually conspicuous, somewhat triangular dark brown speckles lateral to the anal-fin origin, a pointed snout with paired rostral plates, numerous lateral abdominal plates, a single series of large median abdominal plates, numerous dentary and premaxillary teeth, and several morphometric proportions of the body and head, mostly involving prepelvic, prepectoral, and preanal distances, head and cleithral width, caudal peduncle length, and dorsal-fin spine. The new species represents the first record of the genus Curculionichthys in the Madeira River basin and is the most westerly distribution in the Amazon.

Morphological variations in marine pufferfish and porcupinefish (Teleostei: Tetraodontiformes) from Tamil Nadu, southeastern coast of India

In the present study, morphological variations in 14 species of two families, Tetraodontidae and Diodontidae, were examined for individuals collected from five different centres in Tamil Nadu in the southeastern coast of India. Twenty-seven morphological measurements and four meristic characters were taken and used for multivariate analyses such as discriminant function analysis (DFA) &amp; MANOVA. DFA revealed that the first two functions accounted for more than 75% variation between the species. Negative allometric values were observed on head length (HL), orbital length (OL), pupil diameter (PD), interorbital length (IOL), pectoral-fin length (PEL), caudal peduncle depth (CPD), dorsal to pectoral fin distance (DPFD), caudal peduncle length (CPL) and post-pectoral-fin length (POPFL) measurements. Also, MANOVA supported the DFA results. Additions, allometric relationships, and meristic variations were observed for most of these species. Moreover, this is the first attempt to describe a greater number of morphological features of the species belonging to the order Tetraodontiformes.

Cloning, SNP detection, and growth correlation analysis of the 5' flanking regions of two myosin heavy chain-7 genes in Mandarin fish (Siniperca chuatsi).

Myosin heavy chains (MYHs) play important roles in muscle growth and contraction. In fish, MYHs contribute to hyperplasia and hypertrophy of muscle fibers, which can continue into adult life and thus result in indeterminate growth in some species. We previously identified two MYH genes, MYH-7a and MYH-7b, that are differentially expressed in Mandarin fish (Siniperca chuatsi) and appear to function in early growth. However, the regulatory role of their 5' flanking regions is unknown. To examine the effects of single nucleotide polymorphisms (SNPs) in these regions, we used genome walking to amplify their flanking sequences and analyzed the regulatory elements and binding sites. A single SNP locus was found in the flanking sequence of each gene. These SNP loci are located in the conserved glucocorticoid receptor binding region (MYH-7a: G-614A; Allele frequency: G:A = 94.9:5.1; GG (89.76) and AG (10.24) genotypes) and the LIM homeobox domain transcription factor binding sequence (MYH-7b: C-1933A; Allele frequency: C:A = 54.8:45.2; AA (20.82), AC (48.81), and CC (30.37) genotypes). At the G-614A loci, the GG genotype exhibited more superior growth traits (total length, body length, body height, etc.) than the AG genotype, with the exception of caudal peduncle length. Alternatively, at the C-1933A loci, the AC and AA genotypes showed significant differences in all growth traits, except for head length, with AC exhibiting superior traits. The AA and CC genotypes showed significant differences in caudal peduncle length and height, while no differences were observed between the AC and CC genotypes. Thus, these SNPs in the 5' flanking regions of MYH-7a and MYH-7b are correlated with superior growth and can be used for selecting Mandarin fish during breeding.

Six New Species of the Cichlid GenusOtopharynxfrom Lake Malaŵi (Teleostei: Cichlidae)

The endemic Lake Malaŵi cichlid genus Otopharynx is increased from 14 species to 20 by the description of six new species collected from inshore sandy or intermediate rocky/sandy areas or trawled in depths to 59 m. Otopharynx alpha is distinguished from congeners by its unique melanin pattern with suprapectoral spot discrete but supraanal and precaudal spots connected to form a stripe, and by its distinctively shaped pharyngeal bone with numerous small, crowded teeth. Otopharynx mumboensis, thought to be endemic to Mumbo Island, is separated from most congeners by a suprapectoral spot placed entirely below the upper lateral line, and from all others by the combination of 13 gill rakers, pharyngeal bone with posterior margin nearly straight, crowns of all pharyngeal teeth in the median columns broadened and flattened, head length 30.9–32.2% SL, body depth 35.5–36.1% SL, and lower jaw 35.7–36.2% HL. Otopharynx styrax has a more elongate body (depth 24.3–28.6% SL) than any congener. Otopharynx aletes can be diagnosed by the combination of a suprapectoral spot overlapping the upper lateral line, seven or eight vertical bars below the dorsal-fin base, 10 or 11 gill rakers, 34–36 scales in the lateral line, lower pharyngeal bone with molariform posteromedian teeth, and caudal peduncle length 1.6–2.0 times its depth. Otopharynx panniculus is diagnosed by the combination of a prominent square suprapectoral spot spanning subdorsal bars 3 to 4, no dorsal midline spots, 13–15 gill rakers, 31–33 scales in the lateral line, 15 or 16 dorsal-fin spines, absence of a lacrimal notch, and slightly enlarged teeth in the median columns of the lower pharyngeal bone. Otopharynx peridodekamost closely resembles O. panniculus and shares the loss of the lacrimal notch, but has 34–35 scales in the lateral line and 11–13 gill rakers. Photographs of living or freshly collected specimens of five of the new species are provided.

Description of four new species of freshwater gobies from the Black River drainage in China and Vietnam (Teleostei: Gobiidae).

Four new species of Rhinogobius Gill 1859 are described from the Black River drainage in China and Vietnam. Rhinogobius coccinella, new species, and R. nanophyllum, new species, are described from the Mengyejiang River in Yunnan, China. Rhinogobius coccinella is diagnosed by having the cheek and operculum with about 25 large dark spots and branchiostegal membrane unmarked; caudal-peduncle depth 11-12% SL; 1-5 predorsal scales; 27-30 midlateral scales; and 28 vertebrae. Rhinogobius nanophyllum is diagnosed by having the cheek, operculum and pectoral-fin base with about 90 indistinct white marks, caudal fin plain-colored, second dorsal fin magnified with a very broad dark gray median band and a broad white proximal band in males; caudal-peduncle length 22-25% SL and pectoral-fin length 21-24% SL in males; head width at operculum 53-58% HL in males, 58-61% HL in females; 0 predorsal scales; 8-10 branched rays in the second dorsal fin; 7-8 branched anal-fin rays; and 28 vertebrae. Rhinogobius ngutinhoceps, new species, is described from the Nam Na River in Lai Chau, Vietnam. It differs from all congeners by the presence of a supraotic pore β; cheek and operculum with about 65 dark marks and branchiostegal membrane unmarked in males; snout pointed; lower jaw conspicuously protruding; predorsal length 40-41% SL; 12-15 predorsal scales; and 29 vertebrae. Rhinogobius phuongae, new species, is described from the Nam Mu River in Lai Chau, Vietnam, and is diagnosed by having the cheek with about 25 indistinct dark spots and branchiostegal membrane with pale spots in males; operculum unmarked; flank plain-colored in males; a conspicuous black blotch between spines I and III of the first dorsal fin; unpaired fins with a very broad white distal band; pectoral-fin length 20-21% SL; 8-10 predorsal scales; 8-9 branched rays in the second dorsal fin; and 28 vertebrae. A key to the species of Rhinogobius occurring within the Red River drainage is given.

Morphometric and meristic comparison of local and Thai Anabas testudineus

Local and Thai climbing perch, Anabas testudineus are locally known as koi in Bangladesh. These two are important natural and cultured fish. This study was carried out the comparative investigations on morphometric and meristic of local and Thai A. testudineus. Both the varieties were collected from different fish markets in and around Savar. The morphometric characteristics were higher in Thai koi than local and among them; total length, standard length (SL), length of 1st and 2nd dorsal fin bases, length of 1st and 2nd anal fin bases, abdominal regional length were found different. Proportion of SL and head length (HL), HL and snout length, SL and caudal peduncle length were different between the two varieties. Among the meristic characteristics; number of dorsal spines, dorsal fin rays, anal spines, scale on upper lateral line were found difference between local and Thai koi. The body spots and the colour at pelvic fin region were also different. The present study suggested that local and Thai koi are morphometrically and meristically different in many aspects.

A new species, Propherallodus longipterus, from the Philippines and redescription of P. briggsi Shiogaki and Dotsu 1983 (Gobiesocidae: Diplocrepinae)

Propherallodus longipterus sp. nov. (Gobiesocidae: Diplocrepinae) is described on the basis of three specimens (17.0–22.8 mm in standard length: SL) from the Philippines. The new species is characterized by the following characters: 8 or 9 dorsal-fin rays; 8 anal-fin rays; 23 or 24 pectoral-fin rays; 34 vertebrae; upper end of gill membrane level with 7th or 8th pectoral-fin ray base in lateral view; posterior nostril located slightly behind anterior margin of eye; head size moderate, length 30.3–32.1% of SL; disc size moderate, length 19.4–21.5% SL; caudal-peduncle depth 8.7–9.7% SL, 1.5–1.8 in caudal-peduncle length; dorsal- and anal-fin bases long, 14.8–17.8 and 15.7–17.3% SL, respectively; pre-dorsal-fin length 66.8–69.0% SL; dorsal-caudal length 31.1–31.8% SL. Propherallodus briggsi Shiogaki and Dotsu 1983, the most similar congeneric species, is redescribed on the basis of 10 specimens, including the holotype, and morphological changes with growth considered.

NEW RECORD OF THE KIZILIRMAK KILLIFISH (Aphanius marassantensis Pfleiderer, Geiger &amp; Herder, 2014) FROM SÜREYYABEY DAM LAKE IN YEŞİLIRMAK BASIN

The aim of this was to quantify morphometries characteristic of Aphanius marassantensis from Süreyyabey Dam Lake in 2016. Some morphometric characters of samples were measured. These characteristics were standard length (SL), total length (TL) body weight (W), head length, preorbital distance, eye diameter, postorbital distance, head depth, predorsal distance, prepelvic distance, preanal distance, pectoral fin - pelvic fin distance, pelvic fin - anal fin distance, body depth, dorsal fin (anterior end) – anal fin distance, dorsal fin (posterior end) – anal fin distance, postdorsal distance, postanal distance, caudal peduncle length (dorsal), caudal peduncle length (ventral), caudal peduncle depth, dorsal fin base length, anal fin base length, pectoral fin length, pelvic fin length, dorsal fin length, anal fin length. The SL of 100 individuals ranged from 20 to 38 mm. The TL of individuals were between 28 and 45 mm, and W ranged between 0.37 and 1.91 g.

Meristic and Morphometric Characteristics of five-lined snapper, Lutjanus quinquelineatus (Bloch, 1790) from the Red Sea, Egypt

In the present study, 120 fish specimens (64 male and 56 female) of the five-lined snapper, Lutjanus quinquelineatus of variable sizes were used for demonstration the morphometric and meristic characteristics of this species in the Egyptian Red Sea, Hurghada fishing area. The total length varied from 15.3 to 28.7 cm in males and from 16.0 to 31.7 cm in females while their weights ranged between 44 and 378 g in males and between 48 and 512 g in females. This fish species showed constant meristic characters. Statistical interpretation of morphometric data indicated that there is direct relationship between total body length with head length (HL), snout length (SnL), eye diameter (ED) and length of caudal peduncle (CPL). The meristic characters like dorsal fin rays, anal fin rays, lateral line scales, gill rakers on lower arm and scales in transversal line were counted. The results revealed that there is no sexual dimorphism in L. quinquelineatus from Hurghada fishing area.

Genetic and Morphological Analyses Demonstrate That Schizolecis guntheri (Siluriformes: Loricariidae) Is Likely to Be a Species Complex.

Schizolecis is a monotypic genus of Siluriformes widely distributed throughout isolated coastal drainages of southeastern Brazil. Previous studies have shown that fish groups found in isolated river basins tend to differentiate over time in the absence of gene flow, resulting in allopatric speciation. In this study, we used partial sequences of the mitochondrial gene COI with the analysis of the General Mixed Yule Coalescent model (GMYC) and the Automatic Barcode Gap Discovery (ABGD) for single locus species delimitation, and a Principal Component Analysis (PCA) of external morphology to test the hypothesis that Schizolecis guntheri is a complex of species. We analyzed 94 samples of S. guntheri for GMYC and ABGD, and 82 samples for PCA from 22 coastal rivers draining to the Atlantic in southeastern Brazil from the Paraná State to the north of the Rio de Janeiro State. As a result, the GMYC model and the ABGD delimited five operational taxonomy units (OTUs – a nomenclature referred to in the present study of the possible new species delimited for the genetic analysis), a much higher number compared to the traditional alfa taxonomy that only recognizes S. guntheri across the isolated coastal rivers of Brazil. Furthermore, the PCA analysis suggests that S. guntheri is highly variable in aspects of external body proportions, including dorsal-fin spine length, pectoral-fin spine length, pelvic-fin spine length, lower caudal-fin spine length, caudal peduncle depth, anal width and mandibular ramus length. However, no exclusive character was found among the isolated populations that could be used to describe a new species of Schizolecis. Therefore, we can conclude, based on our results of PCA contrasting with the results of GMYC and ABGD, that S. guntheri represents a complex of species.

A New Glyptosternine Catfish from Northern Myanmar (Teleostei: Siluriformes: Sisoridae)

A new species of sisorid catfish in the genus Exostoma is described from the upper Irrawaddy River drainage in northern Myanmar. The new species can be distinguished from congeners by the condition of the posterior extremity of the adipose-fin base, the degree of tuberculation in the preorbital area, as well as morphometric data for the nasal barbel length, snout length, interorbital distance, adipose fin-base length, body depth at anus, caudal-peduncle length, and caudal-peduncle depth. The taxonomic status of congeners in the Irrawaddy River drainage is also discussed, and E. chaudhurii is revalidated as a distinct species.