Caudal Peduncle Research Articles

Dataset for the morphological and erythrocytes parameters of Clarias gariepinus, Pangasianodon hypophthalmus, and their reciprocal hybrids.

Discrimination of different fishes can be done through different means which includes morphological appearance. When two fishes are successfully hybridized, they produce progenies that have shared morphology between their pure parent, hence, making morphometric characterization an important aspect of hybrid discrimination. However, erythrocyte characterization is also a simpler method for characterization. The dataset presented in this article represents the traditional morphological data, truss network data and erythrocyte data of pure and novel hybrids from reciprocal crosses of African catfish Clarias gariepinus and Asian catfish Pangasianodon hypophthalmus. Breeding of the broodstocks was done to produce pure and hybrid progenies which were maintained for a period of four to six months. Based on the cross combinations and morphotypes, traditional measurement of twenty-five morphological characters and five meristic counts were recorded. Thereafter pictures of the different fish groups were used to determine values of thirty-six distances between ten landmark points. The morphological abnormality of the hybrids at market size is also presented in this data article for the very first time. Blood was then collected from the caudal peduncle of ten fish per group and smeared on a slide for observation under a compound microscope (at 100 × magnification). Data gotten included erythrocytes parameters such as cell major axis, cell minor axis, nucleus major axis, nucleus minor axis cell area, nucleus area, cell volume, and nucleus volume. Data recording was through the Microsoft excel spreadsheet; which was also used to process the data to get the exclusive ranges of values for paired progenies. The data as presented is associated with the research article “Morphological characterization of the progenies of pure and reciprocal crosses of Pangasianodon hypophthalmus (Sauvage, 1878) and Clarias gariepinus (Burchell, 1822)” [1]. The dataset presented in this article can be used for easy identification of the novel hybrid progenies of the African Catfish and Asian Catfish.

Differential Performance of Sympatric Pomoxis Species Is Explained by Habitat‐Linked Morphology

AbstractBlack Crappie Pomoxis nigromaculatus and White Crappie Pomoxis annularis have contrasting patterns of performance along a gradient of turbidity for reasons that have yet to be elucidated. We examined how distinct, habitat‐linked morphologies of these congeners make Black Crappie more specialized for structurally complex vegetation and White Crappie more specialized for open‐water habitats and tested how these interspecific differences during early life influence their vulnerability to predation within open‐water and vegetated habitats. Juvenile Black Crappie had deeper bodies with a short, deep caudal peduncle, and juvenile White Crappie had more fusiform bodies with an elongated caudal peduncle. These morphological differences had important consequences for predator evasiveness in each habitat, where Black Crappie were more successful at evading capture in vegetation and White Crappie were more successful at evading capture in open water. Because turbid lakes rarely support vegetation and clear lakes are heavily vegetated, our results suggest that differential success observed between these congeners may be better explained by adaptations to structural habitat complexity rather than tolerance to turbidity. Our study supports that habitat‐linked morphological variation is critically important for predator evasiveness and can structure populations across species distributions.

Vanmanenia intermedia Fang, 1935, a valid hill-stream species of loach (Teleostei: Gastromyzontidae) from the middle Yangtze River basin, Southwest China.

Vanmanenia intermedia, which has long been synonymized with V. pingchowensis since 1980, is here revalidated using morphological characters and molecular evidences, and redescribed on the basis of topotypic specimens. This species is distinguished from all other congeneric species by the following combination of characters: triangular-shaped rostral lobules without secondary rostral barbels; distal edge of dorsal-fin slightly concave; no longitudinal black stripe on the flank; a longer snout (length 52.6-64.5 % of HL); a more backwards-placed anus (the vent to anal distance 34.7-46.1% of the pelvic to anal distance); a slender caudal peduncle (depth 9.1-11.3 % of SL); a longer anal-fin base (length 7.5-9.5 % of SL); and a smaller gill opening with its upper extremity closer to the level of the lower margin of the orbit. The validity of V. intermedia is also confirmed by its significant cyt b gene sequence divergence with all sampled congeneric species and its monophyly recovered in the cyt b gene-based phylogenetic analysis.

Landmark-based geometric morphometrics analysis of body shape variation among populations of the blue jack mackerel, Trachurus picturatus, from the North-East Atlantic

Phenotypic variation in fish can indicate exposure to different environmental conditions, affecting species growth and maturation rates and/or be a consequence of genetic factors that allow fish adaptation to different environments. Understanding population structure and dynamics is extremely important for the establishment of sustainable fisheries. The blue jack mackerel, Trachurus picturatus, is an important fishery resource of the North-East (NE) Atlantic. Fish were captured in six sampling locations in the NE Atlantic - Azores, Madeira, Canaries and Portugal mainland - Matosinhos, Peniche and Portimão. The phenotypic diversity of the species was studied using body landmark-based geometric morphometrics. A truss box method was followed and 30 distance variables were extracted from digital images. Additionally, the temporal stability of the morphological characters was investigated by comparing samples from two different years: 2016 and 2019. The transformed distances were analysed by univariate and multivariate statistics. The Macaronesia region – Azores, Madeira and Canaries – and Portugal mainland displayed a clear phenotypic pattern. Distances related to the body width and caudal peduncle were the most significant variables explaining the observed phenotypic heterogeneity. Furthermore, this study also showed that T. picturatus can exhibit fast phenotypic adaptations to the surrounding environment, observed by the discrimination of Peniche in 2019. Nevertheless, the high overall allocation of individuals to the original location observed for both years (78% in 2016 and 83% in 2019) suggests that the population of T. picturatus in the NE Atlantic is phenotypic heterogeneous. These findings corroborate previous studies and have implications for fishery management.

A new species of Pimelodella Eigenmann amp; Eigenmann, 1888 (Siluriformes: Heptapteridae) from the Orinoco River basin.

A new species of Pimelodella is described from western Andean tributaries of the Orinoco River basin. The new species differs from all congeners by a unique set of characters that includes long maxillary barbel, surpassing the dorsal lobe of the caudal fin; relatively short adipose fin (32.8-36.4 of SL); 40-42 total vertebrae; posterior margin of pectoral-fin spine with 12-18 retrorse dentations along basal two thirds; laterosensory canal foramina of dentary and preopercle large and externally conspicuous; a brown faint and narrow midlateral stripe extending from the pseudotympanum, fading posteriorly along the caudal peduncle, and ending as a spot at the caudal-fin base; and dorsal-fin base darkly pigmented, from spinelet to posteriormost interradial membrane. Taxonomic status of P. pallida and presence of P. cruxenti in Colombia are also discussed.

A New Family Salwaichthyidae (Pisces, Perciformes s.l.) from the Lower Oligocene of the Caucasus and Carpathians

Salwaichthys paratethyensis gen. et sp. nov., representative of a new monotypic family of perciform fishes Salwaichthyidae, is described based on three specimens from the lower Oligocene of the Caucasus (Abkhazia and SW Russia, Adygea) and Polish Carpathians. The new family is characterized by: elongated body with relatively small head and long caudal peduncle, large mouth, divided dorsal fins, numerous (about 55) vertebrae and their rostro-caudal compression, and small cycloid scales. Salwaichthys shares a number of apomorphic features with members of certain perciform families, most notably the Propercarinidae. However, because of its unique combination of features, the new family cannot be properly placed within any known perciform suborder and it is placed herein incertae sedis among the Perciformes.

A New Species of Hypomasticus from Eastern Brazil Based on Morphological and Molecular Data (Characiformes, Anostomidae)

A new species of Hypomasticus is described from the Rio de Contas, a coastal drainage of eastern Brazil, and its phylogenetic position is proposed based on molecular data. The new species is diagnosed among Anostomidae by possessing a downturned mouth with compressed teeth arranged side by side, 37 or 38 lateral-line scales, three scale series between the dorsal-fin origin and the lateral line and between the lateral line and the pelvic-fin origin, and 12 scale rows around the caudal peduncle. Mitochondrial DNA sequences provide evidence that the new species is closely related to H. mormyrops, H. thayeri, H. copelandii, and H. steindachneri, a clade of species endemic to coastal drainages of eastern Brazil. These results combined with a previous phylogeny support the reallocation of the latter two species from Leporinus to Hypomasticus . The new species is herein considered to be Endangered under the IUCN criteria, due to a small Extent of Occurrence, severely fragmented population, and continued decline of area, extent, and quality of habitat.

A Novel Species of Sisorid Catfish, <I>Pseudecheneis nagalandensis</I> sp. nov., (Teleostei: Sisoridae) from the Chindwin Basin of Nagaland, India

A novel sisorid catfish, Pseudecheneis nagalandensis sp. nov., collected from the Tizu River, Chindwin Basin, Nagaland, northeast India is described. This new species differs from its congeners due to the presence of a long ray of pelvic fin that extends up to anal-fin origin, slender caudal peduncle and the thoracic adhesive apparatus with 13−14 transverse ridges which are separated by grooves. This is the only species of the genus Pseudecheneis currently known from Nagaland.

The Analysis of Biomimetic Caudal Fin Propulsion Mechanism with CFD.

In nature, fish not only have extraordinary ability of underwater movement but also have high mobility and flexibility. The low energy consumption and high efficiency of fish propulsive method provide a new idea for the research of bionic underwater robot and bionic propulsive technology. In this paper, the swordfish was taken as the research object, and the mechanism of the caudal fin propulsion was preliminarily explored by analyzing the flow field structure generated by the swing of caudal fin. Subsequently, the influence of the phase difference of the heaving and pitching movement, the swing amplitude of caudal fin, and Strouhal number (St number) on the propulsion performance of fish was discussed. The results demonstrated that the fish can obtain a greater propulsion force by optimizing the motion parameters of the caudal fin in a certain range. Lastly, through the mathematical model analysis of the tail of the swordfish, the producing propulsive force principle of the caudal fin and the caudal peduncle was obtained. Hence, the proposed method provided a theoretical basis for the design of a high-efficiency bionic propulsion system.

Revision of the genus Seminemacheilus, with the description of three new species (Teleostei: Nemacheilidae).

The nemacheilid genus Seminemacheilus is revised. Six species are recognised, three of them described herein as new. All species are endemic to Central Anatolia. Seminemacheilus lendlii from the Sakarya River drainage and the endorheic Lake Aksehir and Eber basins, S. ispartensis from Lake Eğirdir basin and S. ahmeti from Sultan Sazlığı are valid species. Although Seminemacheilus lendlii and S. ispartensis have almost identical COI sequences, they are distinguished by the shape of the caudal peduncle and the presence of scales on the caudal peduncle in S. ispartensis (vs. absent in S. lendlii). Seminemacheilus attalicus, new species, from Kırkgöz drainage, is distinguished by having a slightly emarginated caudal fin, a central pore in the supratemporal canal and a marbled flank pattern. Seminemacheilus ekmekciae, new species, from Lake Tuz basin is distinguished by having a roundish caudal fin, a short post-dorsal length and large brown blotches fused into stripes on the flank. Seminemacheilus tubae, new species, from Lake Beyşehir basin, is distinguished by having a truncate caudal fin and 2-5 (6) supraorbital head pores. Seminemacheilus dursunavsari from the Göksu River drainage is not a valid name and this population is identified as S. tubae.

Larval identification based on melanophore patterns in two Auxis species, bullet tuna Auxis rochei and frigate tuna Auxis thazard, from the northwest Pacific Ocean

Larvae of Auxis rochei and Auxis thazard are commonly found in tropical to temperate waters around the world; however, their identification is difficult due to their similar morphological characteristics. In order to determine the morphological differences between larvae of these two species, we identified larvae of 192 A. rochei and 119 A. thazard using species-specific genetic markers and compared their melanophore patterns at each growth stage. The larvae of both species ranged from 3.5 to 6.9 mm in length and were identified with high accuracy based on the patterns of melanophore distribution at the snout tip and on the caudal peduncle. Using these morphological characteristics, we developed an identification key for the larvae of these two Auxis species based on their growth stage.

Morphometric and meristic characteristics of an endemic Lagusia micracanthus Bleeker, 1860 in the rivers of Maros and Wallanae Cenrana Watersheds

Pirik (Lagusia micracanthus Bleeker, 1860) is one of endemic fishes in Sulawesi. Morphometric and meristic information of Pirik population in various habitats are unknown. The present study aimed to determine the morphometric and meristic variation of Pirik in Maros and Wallanae Cenrana watersheds. Sampling collection was carried out monthly from May 2018 to April 2019 in the Maros watershed, namely Pattunuang River (M1), Bantimurung River (M2), Pucak River (M3); and in Wallanae Cenrana watershed particularly in Camba River (W1), Sanrego River (W2), and Ompo River (W3). Morphometric measurements consisted of 31 characters and meristic measurements consisted of 10 characters. Morphometric data was standardized by dividing all morphometric characters by standard length (SL). Analysis of variance (ANOVA) and discriminant analysis (Discriminant Function Analysis) were applied for data analysis. The results showed that the Pirik taken from rivers in the Maros and Wallanae Cenrana watershed are two different population groups. There are 12 distinguishing morphometric features for Pirik of the Maros and Wallanae Cenrana watershed, i.e. TL (total length), SL (standard length), BDdSA (body depth-dorsal fin origin), HL (head length), Jlup (upper-jaw length), PAfL (pre-anal fin length), ABL (Anal fin base length), PelRL (pelvic ray length), AFRL (anal fin ray length), CPL (caudal peduncle length), CLLup (upper caudal lobe length) and CLLmid (mid-caudal length). There is no significant difference of meristic characters of Pirik obtained from the Maros and Wallanae Cenraa watersheds.

A New Species of Chromis (Teleostei: Pomacentridae) from Mesophotic Coral Ecosystems of Rapa Nui (Easter Island) and Salas y Gómez, Chile

A new species of Chromis (Teleostei: Pomacentridae) is described from three specimens collected at 90 m depth in a mesophotic coral ecosystem at Rapa Nui, Chile. Chromis mamatapara, new species, can be distinguished from its congeners by the following combination of characters: dorsal-fin rays XIV,13–14; pectoral-fin rays 18–19, third from top of fin longest; tubed lateral-line scales 18; total gill rakers on first arch 30–32; vertebrae 11+15; and by coloration of living specimens, especially the presence of a single, pronounced, white spot, roughly the same diameter as the orbit, located where the posterior base of the dorsal fin intersects the caudal peduncle. The most similar DNA barcode (mitochondrial COI gene), among those available, is Chromis tingting from Japan (3.5% uncorrected divergence); however, C. mamatapara, new species, also superficially resembles other species for which sequences are unavailable for comparisons, including C. okamurai from Japan and C. struhsakeri from Hawaii. Due to the high geographic isolation and consequently high endemism in the Rapa Nui region, we believe that C. mamatapara, new species, is endemic to mesophotic ecosystems of Rapa Nui, Isla Salas y Gomez, and nearby seamounts, a discovery that contributes to the high endemism of the region and thus the need for conservation efforts.

Parupeneus williamsi, a new species of goatfish (Perciformes: Mullidae) endemic to the Marquesas Islands, French Polynesia

A new species of goatfish, Parupeneus williamsi, is described on the basis of 12 specimens (43.9–234.3 mm in standard length) collected from the Marquesas Islands, French Polynesia. The species closely resembles Parupeneus multifasciatus (Quoy and Gaimard 1825) in sharing white to yellowish barbels, its tips usually extending beyond the posterior margin of the preopercle, two or three blackish vertical bands (including indistinct bands) on the trunk, and a blackish saddle on the upper caudal peduncle. However, the new species is distinguished from P. multifasciatus by having all of the bands and saddle very indistinct, dense melanophores uniformly distributed on the anal-fin membranes (preserved specimens), upper jaw slightly slender and shorter in specimens larger than 50 mm SL, and slightly longer second anal-fin soft ray. The morphological differences between the two species are supported by a previously published molecular analysis of mitochondrial cytochrome b sequences. Although P. multifasciatus is widely distributed in the eastern Indian and Pacific oceans, P. williamsi is endemic to the Marquesas Islands.

Sarcocheilichthys vittatus, a new species of gudgeon (Teleostei: Cyprinidae) from the Poyang lake basin in Jiangxi Province, South China.

Sarcocheilichthys vittatus, a new species of gudgeon, is described from the Gan-Jiang and Fu-He flowing into the Poyang Lake Basin in Jiangxi Province, South China. It is similar to S. parvus and S. caobangensis in having a longitudinal black band extending from the snout tip to the caudal-fin base, a character separating them from all other congeneric species, but distinct from S. parvus in having more lateral-line scales, no longitudinal yellowish stripe above the lateral black band on the flank and no barbels, and from S. caobangensis in possessing two shorter lateral lobes of the lower lip restricted only to the side of the lower jaw, no black spots along the dorsal-fin base and a stouter caudal peduncle. Its validity was also warranted by a molecular phylogenetic analysis based on the cyt b gene. Critical notes were provided on some currently recognized Chinese congeners.

Apogon soloriens, a new species of cardinalfish (Perciformes: Apogonidae) from the Bonin Islands, Japan

The new cardinalfish Apogon soloriens is described on the basis of nine specimens collected from the Bonin Islands (northern island chain of Ogasawara Islands), Japan. The new species resembles Apogon caudicinctus Randall and Smith 1988 in coloration, lacking a black band below the second dorsal fin but with a black band on the caudal peduncle, but differs in having 13 pectoral-fin rays (vs. 12 rays in A. caudicinctus), greater interorbital width [9.1–11.1% of standard length (mean 9.8%) vs. 6.6–7.9% (7.3%)], and a wider blackish band on the caudal peduncle (vs. narrower black band). A key to the Apogon talboti look-alike group is provided.

An automatic method of fish length estimation using underwater stereo system based on LabVIEW

The underwater non-contact methods for fish length measurement play an important role in aquaculture for fish sorting, grading and effective management. One challenge is to obtain the fish length data automatically instead of to locate the key measurement points of fish manually during the processing. This study presents a stereo vision system with procedure that obtains the oplegnathus punctatus fish body length based on LabVIEW. The key measurement points of fish snout tip and caudal peduncle can be automatically extracted through the processing algorithm that is based on the contour and convex hull calculation. The experiment validated the success rate and accuracy of fish length estimation at different angles of the free-swimming fish body to the optical axis. Experimental results showed that the proposed system could estimate the fish length with high accuracy and success rate. The regression analysis between estimated and manually measured body length showed a good linear relationship with R2 > 0.91 and mean relative error <2.55%. These findings indicated that the proposed system for non-contact and automatic fish body length measurement could be applied in the fish farm.

&lt;i&gt;Glyptothorax distichus&lt;/i&gt;, a New Species of Catfish (Teleostei: Sisoridae) from Mizoram, North-Eastern India

A new sisorid catfish, Glyptothorax distichus, is described from the Barak-Meghna-Surma drainage in Mizoram, North-east India. It is distinguished from its congeners in having a combination of the following characters: a chevron-shaped thoracic adhesive apparatus, with poorly developed median depression that is widely opened posteriorly by skin ridges; short dorsal fin spine; short and slender caudal peduncle; unculiferous ridges of adhesive apparatus not extending anteriorly onto gular region; absence of plicate on ventral surfaces first pectoral and pelvic fins rays, smooth skin on head and body; presence of two broad pale cream longitudinal stripes on body; and 20 + 17 Vertebrae.

Larval development and osteology of Callanthias platei (Teleostei: Callanthiidae) from Desventuradas Islands, South Pacific

Larvae of the Juan Fernández Splendid Perch, Callanthias platei Steindachner, 1898 (Teleostei: Callanthiidae), are described for the first time. The five available specimens, ranging from 3 mm notochord length (NL) to 6.1 mm standard length (SL), were collected with plankton nets near Desventuradas Islands, Southeast Pacific, during the austral spring of 2015 and 2016. The larvae are deep bodied with a narrow caudal peduncle, a large head and a triangular, coiled gut. The pigmentation is scarce in preflexion larvae but increases after flexion. All individuals have several groups of head spines: anterior and posterior preopercular, interopercular, subopercular, opercular and supracleithral. The formation of all fins occurs early in development, with the pectoral fins appearing first and the pelvic fins last. The osteological development of the skull, vertebral column, fins, and scales are described.

A new endangered species of Megaleporinus (Characiformes: Anostomidae) from the Rio de Contas basin, eastern Brazil.

A new species of Megaleporinus is described from the Rio de Contas, a coastal drainage of eastern Brazil, and its phylogenetic relationships are studied using molecular data. The new species is unique among Anostomidae by possessing two exclusive features: an irregular dark longitudinal stripe from supracleithrum to second midlateral blotch and anterior cranial fontanel partially closed. In addition, the new species is diagnosed by having three premaxillary teeth, three dentary teeth, 37 or 38 scales in lateral line, 16 scale rows around caudal peduncle, three dark midlateral blotches on body, and red fins in life. The new species is closely related to M. obtusidens from the São Francisco basin, corroborating previous studies that indicated that the latter represents a species complex as currently defined. The new species exhibits the first rib enlarged in mature males, a feature described for some congeners. The new species is herein considered to be Endangered under the IUCN criteria.