Caudal-fin Rays Research Articles

Moenkhausia restricta, a new species from the upper Rio Negro, Amazon basin, northwestern Brazil (Characiformes: Characidae).

A new shallow-bodied species of Moenkhausia is described from the upper Rio Negro, Amazon basin, Brazil. The new species is diagnosed from all congeners by the combination of a body depth not surpassing 33% in SL in adult specimens, seven scale rows between dorsal-fin origin and lateral line, five scale rows between pelvic-fin insertion and lateral line, a single conspicuous vertically elongated humeral blotch, and a conspicuous caudal peduncle blotch extending to the distal margin of the median caudal-fin rays. The new species was collected together with Jupiaba zonata, with which it shares a very similar color pattern. The similarity between these two taxa is interpreted as an additional case of Batesian mimicry between Moenkhausia and Jupiaba.

A new species of miniature Characidium (Characiformes: Crenuchidae) from the upper Rio Paraguay basin, Mato Grosso state, Brazil.

A new miniature species of Characidium is described from the upper Rio Paraguay basin, Brazil. The new species can be diagnosed from all congeners by the presence of a dark-brown humeral blotch, vertically elongated (spanning 5 to 7 horizontal scale rows), with the shape of an upside-down acute triangle. Additionally, it can be diagnosed by a short lateral line (6 to 8 perforated scales), the absence of a conspicuous peduncular blotch, a lower number of principal caudal-fin rays (14-16) and by absence of the adipose fin. The new species is the smallest species of the genus; the largest specimen was 19.3 mm standard length.

Paraliparis hokuto, a new snailfish (Cottoidei: Liparidae) from Suruga Bay, Japan, and a new record of the rare species Paraliparis atramentatus Gilbert and Burke 1912

The new snailfish Paraliparis hokuto is described from two specimens collected between 1,432 and 1,562 m depth in the northern part of the Suruga Trough. It can be distinguished from all currently recognized congeners by the following combination of characters: 72 total vertebrae; 65 dorsal-fin rays; 60 or 61 anal-fin rays; 22 or 23 pectoral-fin rays; 6 caudal-fin rays; 3 pectoral proximal radials, all unnotched; 5 pyloric caeca, longest caecum ca. 60% of HL; teeth weak, easily bent or damaged, completely uniserial in lower jaw; paired chin pores in common pit; opercular flap present; uppermost part of pectoral-fin base horizontally level with center or lower margin of eye. A single specimen of the rare snailfish Paraliparis atramentatus Gilbert and Burke 1912, collected from 253 to 1,282 m depth on the continental slope in western Suruga Bay, and representing only the third example of the species and first record from Suruga Bay, is described and intraspecific variability in teeth tip shape noted.

A new species of Hemigrammus (Characiformes: Characidae) from western Amazon River basin, Colombia

A new species of Hemigrammus is described from the Amazon Basin near Leticia, Departamento Amazonas, Colombia. In common with some congeners and some Hyphessobrycon spp., the new species colour pattern lacks a humeral blotch but has a caudal-peduncle blotch. It can be distinguished from congeners with a similar colour pattern by having: a relatively deep body (30.2%-39.0% LS ), 20-24 branched anal-fin rays, 6-8 perforated scales of the lateral line, anal-fin base without a conspicuous black stripe, 3-5 maxillary teeth, maxillary teeth with 1-3 cusps, a thin longitudinal midlateral line and a well-defined oval shaped caudal blotch, extending from caudal peduncle into the lower caudal-fin rays. Comparisons with congeners and with Hyphessobrycon species sharing the same general colour pattern are presented.

Channa brunnea, a new species of snakehead (Teleostei: Channidae) from West Bengal, India

Channa brunnea, a new species of snakehead fish lacking pelvic fins, from West Bengal, India, is distinguished from its pelvic fin-less congeners by possessing an uniform dark brown body, ochre to bright-orange blotches on the caudal fin, fewer dorsal and anal-fin rays (35-37 vs. 47-51 and 24 vs. 28-32, respectively), fewer vertebrae (43 vs. 45-57), and fewer lateral-line scales (43-46 vs. 51-63). Though Channa brunnea superficially resembles C. bleheri, it can be distinguished from the latter by possessing dark-brown oblique markings on the upper half of the body; transverse scale rows (4½-5½ vs. 3½); pre-anal scales (22-26 vs. 17-20); 2 rows of teeth in the fifth ceratobranchial, the outer row with 16 large conical teeth (vs. 3 rows of teeth, the outer row with 13 large conical teeth); dentary with 20 large, stout, conical teeth in the inner row (vs. 32 medium-sized conical teeth); and a Kimura's two parameter (K2P) distance of 9.8-10.6%.

Stock identification of minor carp, Cirrhinus reba, Hamilton 1822 through landmark-based morphometric and meristic variations

BackgroundWild fish populations stock is continuously diminishing in the Indo-Ganges river basin, and the population status of most fishes is unidentified. The identification of the population status and the conservation of commercially important and endemic wild fish populations in this region are crucial for the management. The aim of this paper was to identify the population status of Cirrhinus reba, a promising aquaculture but vulnerable species in the Indo-Ganges river basin in Bangladesh.MethodsC. reba samples were collected from four isolated populations of the Brahmaputra (n = 30), the Padma (33), the Karatoya (31), and the Jamuna Rivers (30) in Bangladesh, and the population status was evaluated using morphometric and landmark comparisons. Data were analyzed with the Kruskal-Wallis test, univariate analysis, discriminant function analysis, and the formation of a dendrogram.ResultsThree meristic characters (Pectoral fin rays, caudal fin rays, scale in lateral lines), four morphometric characters (head length, pre-orbital length, post-orbital length, maximum body depth), and truss measurement (4–7) were significantly different among the stocks. The step-wise discriminant function analysis retained 15 variables from morphometric and landmark measurements that significantly differentiated the populations based on the constructed DFI and DFII. Discriminate function analysis also showed that 91.2% of the original groups were classified into their correct samples. The cluster analysis of Euclidean distances placed the Jamuna population in one cluster and the Brahmaputra, the Padma, and the Karatoya populations in the second one.Conclusion Morphological differences among the stock were probably due to different ancestral origin. This is the first report about population status of C. reba in their natural habitat of the Indian subcontinent. Further genetic studies and the evaluation of environmental impact on C. reba populations in Bangladesh are suggested to support our findings.

Morphometric and Meristic features and Length-Weight Relationship as indicators of quality of Brycinus macrolepidotus in Lower River Ogun, Nigeria

One Hundred And Eighty samples of True big-scale fish (Brycinus macrolepidotus Valenciennes, 1850) were collected bi-monthly from June – November, 2017, from River Ogun, Nigeria. Total length and body weight of all samples measured and samples were grouped based on length into sizes: juveniles (10-14.9 cm), sub-adults (15.1-19.9 cm), and adults (20.2-26.3 cm). Significant differences (p<0.05) were observed in the meristic characters in all the groups. Dorsal fin ray ranged from 7-9, pelvic fin ray 8-12, caudal fin ray 18-24, pectoral fin ray 7-12, anal ray 12-14 and dorsal spine 0-9 through the wet and dry season for all sizes. Length- Weight relationship for juveniles, sub-adult and adult sizes showed ‘a’, ‘b’ and ‘r’ values for juveniles as -0.82, 2.17 and 0.85, sub-adult as -0.38, 1.82 and 0.90 and adult as 0.44, 1.03 and 0.78 respectively. Mean condition factor recorded was 1.16±0.15, 1.39±0.13, and 2.17±0.59 for adult, sub-adult and juvenile respectively. Conclusively, B. macrolepidotus in this aquatic ecosystem could be in a good environment and quality as condition factor of all sizes were above 1.

A new Creagrutus from the upper rio Xingu basin, Brazil (Teleostei: Characiformes: Characidae)

A new species of Creagrutus is described from the upper rio Xingu basin, Mato Grosso state, Brazil. The new species can be distinguished from its congeners by a combination of characters that includes dorsal fin mostly black, a dark oblique blotch on middle and upper-inferior caudal-fin rays, and presence of only two rows of premaxillary teeth. Creagrutus mucipu, formerly known only from the upper rio Tocantins basin in Brazil, is recorded herein as occurring syntopically with the new species in the upper rio Xingu basin.

Paraliparis variabilidens, a new snailfish (Liparidae) from the Suruga Trough, Japan

The new snailfish Paraliparis variabilidens is described from a single specimen collected between 1,462 and 1,562 m depth in the northern part of the Suruga Trough, Japan. It differs from all currently recognized congeners by the following combination of characters: 67 total vertebrae, 62 dorsal-fin rays, 57 anal-fin rays, 26 or 27 pectoral-fin rays, 9 caudal-fin rays (including 2 procurrent rays), ca. 12 pyloric caeca, mixed simple and trilobate teeth on both jaws, eye diameter 18.1% HL, gill slit extending ventrally in front of 2nd pectoral-fin ray base, deeply notched pectoral fin, body dusky, peritoneum black, and stomach pale.

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.

Rediscovery and redescription of the endangered Hypostomus subcarinatus Castelnau, 1855 (Siluriformes: Loricariidae) from the Rio São Francisco basin in Brazil.

Hypostomus subcarinatus Castelnau, 1855 is rediscovered in the Lagoa da Pampulha, an urban lake in the Rio das Velhas basin (Rio São Francisco system) in the state of Minas Gerais, southeastern Brazil. Herein, H. subcarinatus is redescribed and diagnosed from its congeners based on characters such as blue-tan dorsal fin in live specimens, slender bicuspid teeth, dentaries angled more than 90 degrees, moderate keels along lateral series of plates, small roundish dark spots, one plate bordering supraoccipital, by having nuptial odontodes mainly on pectoral, dorsal and caudal-fin rays, and long anal-fin unbranched ray. The rediscovery of H. subcarinatus more than 160 years after its original description was an unexpected event, because the Lagoa da Pampulha is an artificial, silted and polluted urban lake. The lake is located in downtown Belo Horizonte, the third largest urban agglomeration in Brazil with a population exceeding 5.9 million inhabitants.

Zandtfuro and Schernfeldfuro, new genera of Halecomorphi (Actinopterygii) from the Upper Jurassic Solnhofen Archipelago

ABSTRACTIn the Late Jurassic Plattenkalk deposits of the Solnhofen Archipelago and of Nusplingen (both southern Germany), there are a considerable number of as yet undescribed genera and species of ganoin-scaled Halecomorphi. Some species were preliminarily assigned to the genus ‘Furo’; however, as noted by previous authors, the taxon ‘Furo’ is not a monophyletic genus. A description of two new genera and species, Zandtfuro tischlingeri and Schernfeldfuro uweelleri is presented here, with further descriptions of new species to follow separately. These new taxa are characterized by a specific combination of features, including: body shape; number of suborbital bones, infraorbitals, extrascapulars, dorsal and caudal fin rays, and vertical scale rows; number and shape of maxillary teeth; presence or absence of sclerotic ring ossification; shape of the ventral postinfraorbital; insertion of dorsal, pelvic, and anal fins; position of lateral line in caudal fin area; and shape and distribution of scales. The more basal Halecomorphi with massive ganoin scales (Parasemionotiformes, Panxianichthyformes, and Ophiopsiformes) remain poorly known, compared with the more advanced halecomorph group of the Amiiformes (especially the Amiidae). Closer investigation of their taxonomic relationship is therefore important for understanding broader patterns of halecomorph evolution.

Meristic and Morphometric Variations of Barred Spiny EEL Macrognathus pancalus Populations from Bangladeshi Freshwaters: An Insight Into Landmark-Based Truss Network System

Abstract The present research focuses to examine the meristic and landmark-based morphometric variations of barred spiny eel Macrognathus pancalus from four populations namely Dhakuria beel, Jessore (DBJ); Bohnni boar, Gopalgonj (BBG); the Arial kha river, Madaripur (AKRM) and the Nabaganga river, Jhenidah (NRJ) in Bangladeshi freshwaters. Six meristic counts were compared among four populations and significant differences were observed in number of caudal fin rays and number of pelvic fin rays in all meristic characters. The truss protocol was used in the present study based on six general morphometrics and fifteen truss measurements. Univariate statistics showed that five (standard length (SL), upper jaw length (UJL), lower jaw length (LJL), head depth (HD) and inter orbital (IO)) of six morphometric and eleven truss networks (viz. 2-3, 3-4, 5-6, 6-7, 7-8, 1-8, 2-8, 3-8, 3-7, 4-7 and 5-7) among fifteen truss measurements differed significantly. Cannonical discriminate function analyses were conducted among samples and the populations were fully intermingled. Pooled within-group correlation showed morphometric and landmark measurements; the first discriminant function (DF) accounted for 79%, the second DF accounted for 15.9% and third DF accounted for 5.1% of group variability. An euclidian dendrogram was prepared based on morphometric and truss measurements in four populations, where two clusters were mainly formed, in which first cluster formed by NRJ population was fully separated, and the second cluster was formed by two populations of AKRM and DBJ. Additionally, a subcluster BBG was formed with AKRM. On the basis of morphometric and truss measurements, 68.8%, 83.6%, 55.6% and 80% of original grouped cases were correctly classified in NRJ, AKRM, DBJ and BBG, respectively. These results specify the presence of different stocks of fish from four aquatic habitats. This study is highly significant for proper conservation and effective management of M. pancalus populations as well as for the scientific community for further research.

A new species of Hemigrammus Gill 1858 (Characiformes: Characidae) from the upper Rio Negro, Amazon basin, Brazil.

A new species of Hemigrammus is described from the upper Rio Negro, Amazon basin, Brazil. The new species is distinguished from all congeners by its unique color pattern consisting of a single humeral blotch clearly spaced from a conspicuous midlateral dark stripe, which extends from fifth or sixth anteriormost vertical scale row to the basis of the middle caudal-fin rays. Comments on its putative relationships are provided.

A new glass tetra species of Phenacogaster from the rio Salitre, rio São Francisco drainage, Brazil (Characiformes: Characidae)

ABSTRACT A new species of Phenacogaster is described from the rio Salitre, a tributary of the lower middle rio São Francisco drainage. The new species can be clearly distinguished from all its congeners in having a conspicuous, broad caudal peduncle spot reaching the upper and lower margins of the peduncle with a short extension onto the middle caudal fin rays and another weaker extension over the lower lobe of the caudal fin.

A new species of Astyanax (Characiformes: Characidae) from the rio de Contas basin, Bahia, Brazil

ABSTRACT A new species of Astyanax from tributaries of the rio de Contas, Bahia, Brazil, is described. The new species differs from congeners by having three horizontal series of scales from lateral line to pelvic-fin origin and the distal margin of third infraorbital distinctly separated from vertical and horizontal limbs of preopercle, leaving a broad area not covered by superficial bones. The new species further differs from most congeners by the presence of bony hooks on all fins of mature males. Particularly from congeners occurring in rivers of the Northeastern Mata Atlântica freshwater ecoregion, it further differs by having the highest body depth just anterior to the dorsal-fin origin, 34-37 pored lateral line scales, a vertically elongated conspicuous dark humeral blotch reaching below the lateral line and a conspicuous dark wide midlateral stripe extending from the clear area on the rear of the humeral blotch to the end of middle caudal-fin rays and forming an inconspicuous blotch on caudal peduncle.

Channa royi (Teleostei: Channidae): a new species of snakehead from Andaman Islands, India

A new species of snakehead fish Channa royi sp. nov., has been described based on 21 specimens collected from the South, Middle and North Andaman Islands, India. It is distinguished from all its congeners by a greenish-grey dorsum, pale brown to black pectoral fin with 2-3 inconspicuous semicircular bands, a series of 7-9 obliquely-arranged, saddle-like, dark olive to grey oblique streaks on green background on upper half of the body, 42-45 pored lateral-line scales, 12-13 branched caudal rays, 6-7 pre-dorsal scales, 43 vertebrae, two rows of teeth on the lower jaw, an outer row of numerous minute slender, pointed teeth and single inner row of large uniform sized teeth without any large canine like teeth on the anterior fourth of the lower jaw. Phylogenetically C. royi sp. nov. is closely related to C. harcourtbutleri, with a genetic distance (K2-P) of 2.4-2.8%, but morphologically differs in having greater inter-orbital width, fewer pelvic-fin rays (5 vs. 5-7, mode 6); fewer caudal-fin rays (ii- i, 10-12, i-ii vs. ii, 15, ii); more pre-dorsal scales (6-7 vs. 4) and fewer mid row lateral-line scales (9-13 vs. 15-16). Though Channa royi sp. nov. is a part of C. gachua species-group, it differs from the topotypic C. gachua from Bengal with higher pair-wise sequence distance of 19.5-20.9%.

Channa royi (Teleostei: Channidae): a new species of snakehead from Andaman Islands, India

A new species of snakehead fish Channa royi sp. nov., has been described based on 21 specimens collected from the South, Middle and North Andaman Islands, India. It is distinguished from all its congeners by a greenish-grey dorsum, pale brown to black pectoral fin with 2-3 inconspicuous semicircular bands, a series of 7-9 obliquely-arranged, saddle-like, dark olive to grey oblique streaks on green background on upper half of the body, 42-45 pored lateral-line scales, 12-13 branched caudal rays, 6-7 pre-dorsal scales, 43 vertebrae, two rows of teeth on the lower jaw, an outer row of numerous minute slender, pointed teeth and single inner row of large uniform sized teeth without any large canine like teeth on the anterior fourth of the lower jaw. Phylogenetically C. royi sp. nov. is closely related to C. harcourtbutleri, with a genetic distance (K2-P) of 2.4-2.8%, but morphologically differs in having greater inter-orbital width, fewer pelvic-fin rays (5 vs. 5-7, mode 6); fewer caudal-fin rays (ii- i, 10-12, i-ii vs. ii, 15, ii); more pre-dorsal scales (6-7 vs. 4) and fewer mid row lateral-line scales (9-13 vs. 15-16). Though Channa royi sp. nov. is a part of C. gachua species-group, it differs from the topotypic C. gachua from Bengal with higher pair-wise sequence distance of 19.5-20.9%.

Developmental and bone development indexes of medaka fish at 11 and 16 days of age

The teleost fish medaka (Oryzias latipes) is currently used by laboratories worldwide as a model for many human diseases, including bone diseases. Our research group focuses on a medaka model for osteoporosis. To characterize the bone indexes of diseased animals, the bone development indexes of healthy wild-type fish are required for comparative analysis. Thus, this study examined the developmental and bone development indexes of wild-type medaka larvae at 11 and 16 days of age, the two developmental stages selected for the analysis of diseased patterns in osteoporosis-induced animals. The assessed parameters included the total body length of live larvae, number of caudal fin rays, vertebrae, and neural and hemal arches, as well as the total areas of mineralized vertebrae and lengths of mineralized arches. The obtained data are important for subsequent studies on bones using this fish model.

Exostoma tibetana, a new glyptosternine catfish from the lower Yarlung Tsangpo River drainage in southeastern Tibet, China (Siluriformes: Sisoridae).

Exostoma tibetana, new species, is described from the lower Yarlung Tsangpo River drainage in southeastern Tibet, China. It is distinguished from congeners by having an adipose fin separate from the upper procurrent caudal-fin rays and incised at the posterior extremity of its base; the tip of the pelvic fin not reaching to the anus when adpressed; 10 branched pectoral-fin rays; and morphometric features associated with the body depth, adipose-fin base length, caudal-peduncle depth, snout length, and eye diameter. The validity of this new species was also supported by molecular phylogenetic analysis based on Cyt b gene sequences.