Preanal Vertebrae Research Articles

A new short brown unpatterned moray eel Gymnothorax andamanensis (Muraenidae: Muraeninae) from Andaman waters, India.

Gymnothorax andamanensis sp. nov., a new short brown moray eel, is described here on the basis of two specimens collected from Port Mout, Port Blair, South Andaman (11.659327°N; 92.696148°E), caught using baited hand-lines in a sandy habitat at a depth of less than 2 m. The species is characterized in having the dorsal-fin origin before the gill opening, pre-anal length 2.1-2.2, jaw pores with black rim, two branchial pores, predorsal vertebrae 3, preanal vertebrae 57 and total vertebrae 135-136, teeth smooth, three large fang-like median intermaxillary teeth, biserial maxillary and uniserial vomerine teeth, and dentary teeth biserial with two teeth in each side in the second row of the dentary. The new species is compared with all 10 short brown unpatterned moray eels known from the world and two from Indian waters.

Four new deepwater Ophichthus (Anguilliformes: Ophichthidae) from Japan with a redescription of Ophichthus pallens (Richardson 1848)

In this paper, new and uncertain Japanese snake eels of the genus Ophichthus are treated. Ophichthus kusanagi, O. lupus, O. oligosteus and O. yamakawai are herein described as new species. Ophichthus kusanagi, collected from Suruga Bay of Shizuoka Prefecture, off Owase, Mie Prefecture, and Tosa Bay, Kochi Prefecture, is distinguishable from four similar congeners by having one + four supraorbital and two preopercular pores, 13 pectoral-fin rays, fewer total vertebrae (158–163), a longer tail [58–60% of total length (TL)], a small eye [7.5–9.0% of head length (HL)], an acute snout, a low knob on upper lip between nostrils, relatively slender teeth, and a pointed pectoral fin. Ophichthus lupus, collected from the East China Sea, is characterized by its numerous total vertebrae (180–182), shorter pectoral fins (20–25% HL), and the position of the dorsal-fin origin (slightly behind the pectoral-fin tip); it can be distinguished from similar species in its supraorbital and mandibular pores (one + four and six or seven), arrangements of teeth on its mandible and vomer (almost uniserial), its robust body (depth 2.6–3.1% TL), slightly larger head (7.8–8.1% TL), longer and acute snout (24% HL), longer upper jaw (45–48% HL), absence of protrusion along upper lip, and the narrow dark margin of its dorsal fin. Ophichthus oligosteus, collected from Tosa Bay of Kochi Prefecture, is characterized by its fewer preanal and total vertebrae (46 and 121). Ophichthus yamakawai, collected from Kochi Prefecture, is characterized by its large blotches along the lateral line and numerous preanal and total vertebrae (67 and 172). We refer an uncertain species, Ophichthus stenopterus Cope 1871, to the synonymy of Ophichthus pallens (Richardson 1848), a forgotten species described from China. Pisoodonophis zophistius Jordan and Snyder 1901 is recognized as valid in Ophichthus and a senior synonym of Ophichthys intermedius Regan 1905. Ophichthus habereri Franz 1910, originally described from Yokohama, central Japan, is a junior synonym of Ophichthus asakusae Jordan and Snyder 1901. Pisodonophis sangjuensis Ji and Kim 2011 is referred to Ophichthus. We currently recognize 20 species of Ophichthus from Japan. A key to the Japanese species of Ophichthus and its closely associated group Pisodonophis is provided.

DNA barcoding adjudicate two different morphs of Bascanichthys deraniyagalai (Anguilliformes: Ophichthidae): re-description and first record from Chilika lagoon, India

Morphological characters and distribution pattern of the snake eel, Bascanichthys deraniyagalai is debatable during the past half-century. Thus, the species is re-described herewith by morphometry, vertebrae, and molecular data. In recent Chilika expedition in India, we have collected 10 specimens and observed a vertebral count dimorphism. The present study distinctly detected two vertebral groups of B. deraniyagalai: first group with 5 predorsal vertebrae, 81–83 preanal vertebrae, 190–196 total vertebrae in females; however, the sex of the second group with 5 predorsal vertebrae, 72–74 preanal vertebrae, 176–178 total vertebrae was not able to confirm. Further, the molecular data of morphologically identified two distinct groups of B. deraniyagalai shows negligible Kimura 2 parameter genetic divergence and cohesive clustering in Neighbor-Joining phylogeny proved to be the two different morphs of the same species. Hence, the present study indicated there might be vertebral count or sexual dimorphism in B. deraniyagalai, which need further sampling and taxonomic revision to unwrap the fact.

Recently diverged killifishes: Morphometry and caudal skeleton osteology of two members of the Aphanius dispar species group (Aphaniidae, Teleostei)

Recently diverged killifishes: Morphometry and caudal skeleton osteology of two members of the Aphanius dispar species group (Aphaniidae, Teleostei)

Eels of the genus Bathyuroconger in the northwestern Pacific, with descriptions of four new species (Anguilliformes: Congridae).

Examination of the congrid genus Bathyuroconger in the northwestern Pacific reveals six species are present. Bathyuroconger albus sp. nov. differs from congeners in having a pale coloration, a moderately reduced gill opening that is close to but not touching the pectoral-fin base, trunk length 2.0-2.9 times HL, preanal vertebrae 45-54, preanal lateral-line pores 42-48. Bathyuroconger dolichosomus sp. nov. has a moderately reduced gill opening that is close to but not touching the pectoral-fin base, trunk length 3.2 times HL, preanal vertebrae 63, and preanal lateral-line pores 61. Bathyuroconger fowleri sp. nov. has a small gill opening distant from the pectoral-fin base, trunk length 1.7-2.1 times head length, dorsal-fin origin over middle of pectoral fin, predorsal vertebrae 10-14, preanal vertebrae 48-52, total vertebrae 173-178. Bathyuroconger hawaiiensis sp. nov. has a slightly reduced gill opening, separated from the pectoral-fin base, dark color, total vertebrae 201-210. Bathyuroconger parvibranchialis (Fowler, 1934), redescribed herein, has a small gill opening distant from the pectoral-fin base, dorsal-fin origin over base of pectoral fin, trunk length 1.4-1.7 times in HL, preanal vertebrae 43-48, total vertebrae 181-189, and a uniformly dark color in adults. Bathyuroconger cf. vicinus has a full-size gill opening in contact with pectoral-fin base, dark color, and total vertebrae 196-201. A key to the species in the northwestern Pacific is provided.

First Report of Genus Diploconger (Congridae: Congrinae) from the Indian Coast

Present study reports a moderately elongate, light brown coloured eel, Diploconger polystigmatus Kotthaus, 1968, for the first time from Indian waters. The species is differentiated from other congridae in having the following combination of characters: double row of cephalic and lateral-line pores, dark brown strip from the middle of the supratemporal commissure up to the tip of the mouth, dorsal fin origin nearly from the halfway of pectoral fin, each dorsal fin ray have black spots at the base, pre-dorsal vertebrae 9, pre-anal vertebrae 27, total vertebrae 108. The present report also reports the genus Diploconger for the first time from Indian waters.

Gymnothorax odishi sp. nov. (Muraenidae: Muraeninae), a short brown unpatterned moray eel from Bay of Bengal, India.

Gymnothorax odishi sp. nov., a new short brown moray eel, is described here on the basis of eleven specimens collected from Gopalpur, Odisha, along the east coast of India, Bay of Bengal. The species is characterized with dorsal-fin origin before gill opening, jaw pores with dark rim, small black patch just behind the eye of about eye size or more, gill opening with dark rim, two branchial pores, predorsal vertebrae 4, preanal vertebrae 55-58 and total vertebrae 133-138, three large fang like median intermaxillary teeth, uniserial maxillary and vomerine teeth. The new species is compared with all short brown unpatterned moray eels known from the world.

The caudal skeleton of Arambourgthurus scombrurus (Arambourg, 1967), a Paleogene oceanic surgeonfish

Abstract A detailed description of the caudal skeleton of the Paleogene nasine surgeonfish Arambourgthurus scombrurus is provided herein. The compound (urostylar) centrum is fused with a large, nearly triangular, thick hypural plate, formed by consolidated hypurals 1–4. The compound centrum supports a large autogenous parhypural bearing a thick and blunt hypurapophysis. Hypural 5 is a small triangular bone. There is a single elongate autogenous uroneural and three epurals, the first of which is remarkably stout and elongate, with its proximal end embraced by the open neural arch of the second preural vertebra. The haemal spines of the second and third preural vertebrae are fused to their respective centra. The phylogenetic relationships of Arambourgthurus are discussed. Arambourgthurus shares some features with the Eocene Sorbinithurus and the Miocene Marosichthys, and together they constitute a monophyletic group that represents the sister group of the pair formed by the extant genus Naso and the fossil ...

Vertebral column regionalisation in Chinook salmon, Oncorhynchus tshawytscha.

Teleost vertebral centra are often similar in size and shape, but vertebral-associated elements, i.e. neural arches, haemal arches and ribs, show regional differences. Here we examine how the presence, absence and specific anatomical and histological characters of vertebral centra-associated elements can be used to define vertebral column regions in juvenile Chinook salmon (Oncorhynchus tshawytscha). To investigate if the presence of regions within the vertebral column is independent of temperature, animals raised at 8 and 12 °C were studied at 1400 and 1530 degreedays, in the freshwater phase of the life cycle. Anatomy and composition of the skeletal tissues of the vertebral column were analysed using Alizarin red S whole-mount staining and histological sections. Six regions, termed I-VI, are recognised in the vertebral column of specimens of both temperature groups. Postcranial vertebrae (region I) carry neural arches and parapophyses but lack ribs. Abdominal vertebrae (region II) carry neural arches and ribs that articulate with parapophyses. Elastic- and fibrohyaline cartilage and Sharpey's fibres connect the bone of the parapophyses to the bone of the ribs. In the transitional region (III) vertebrae carry neural arches and parapophyses change stepwise into haemal arches. Ribs decrease in size, anterior to posterior. Vestigial ribs remain attached to the haemal arches with Sharpey's fibres. Caudal vertebrae (region IV) carry neural and haemal arches and spines. Basidorsals and basiventrals are small and surrounded by cancellous bone. Preural vertebrae (region V) carry neural and haemal arches with modified neural and haemal spines to support the caudal fin. Ural vertebrae (region VI) carry hypurals and epurals that represent modified haemal and neural arches and spines, respectively. The postcranial and transitional vertebrae and their respective characters are usually recognised, but should be considered as regions within the vertebral column of teleosts because of their distinctive morphological characters. While the number of vertebrae within each region can vary, each of the six regions is recognised in specimens of both temperature groups. This refined identification of regionalisation in the vertebral column of Chinook salmon can help to address evolutionary developmental and functional questions, and to support applied research into this farmed species.

Gymnothorax pseudotile sp. nov. (Muraenidae: Muraeninae) from Bay of Bengal India

Gymnothorax pseudotile sp. nov., is described based on nine specimens (337–503 TL) collected from the northern Bay of Bengal. The species has intermaxillary teeth in three longitudinal rows, consisting of a median row of three depressible fang-like teeth and a single row of 6 teeth on each side; dorsal-fin origin above the posterior half of the gill opening; both dorsal and anal fin low with pale margin; predorsal vertebrae 12–13, preanal vertebrae 56–59, total vertebrae 126–129 (MVF: 13-58-128). The closely-related Gymnothorax tile, for which a brief description is included, can be differentiated from the new species by having teeth moderately stout, intermaxillary teeth in 5 rows; dorsal-fin origin over or slightly before the gill opening; dorsal and anal fins high with a pale margin, and predorsal vertebrae 9–11.

A new species of the genus Diaphenchelys (Anguilliformes: Muraenidae) from Thailand

A new species of moray eel, Diaphenchelys dalmatian is described based on five specimens [289.8–503.0 mm total length (TL)] collected from the western coast of peninsular Thailand and the Gulf of Thailand. It can be easily distinguished from Diaphenchelys pelonates McCosker and Randall 2007, another species of the genus Diaphenchelys McCosker and Randall 2007, by its coloration (ground color white with brown dalmatian-like spots vs. brown with pale vermiculate pattern). The present new species also differs from D. pelonates in its longer tail (62.0–64.6% TL vs. 59.6–61.5%), fewer infraorbital pores along upper lip (three vs. four), fewer mandibular pores (five vs. six or seven), and fewer vertebral counts (preanal vertebrae 43–46 vs. 55–58; total 126–131 vs. 153–155). Diaphenchelys is closely similar to the genus Strophidon McClelland 1844 in the shape of neurocranium, the elongate body, low vertical fins, eye location, jaw shape, and presence of inner mandibular teeth. However, both differ in the vertebral counts (126–155 in Diaphenchelys vs. 164–208 in Strophidon) and coloration (prominent pattern vs. uniform).

Osteological characters of the axial skeleton and pectoral girdles in some species of the Euroasian freshwater fishes of the family Cottidae

The structure of the pectoral fin, its girdle and osteological details of the axial skeleton and a skeleton of the caudal fin, including the structure of unpaired fins were studied in three species of three genera of the family Cottidae: the genus Cottus: European species C. koshewnikowi Gratzianov, 1907 and two species of Fareastern monotypic genera: Trachidermus fasciatus Heckel, 1837 and Mesocottus haitej (Dybowsky, 1869). The species well differ in structure of the pectoral girdles and pleural ribs. Mesocottus haitej is characterized by absence of the interradial and coracoid fenestrae and by considerable reduction of pleural ribs in the abdomen part of the vertebral column. Сottus koshewnikowi and T. fasciatus have backwardly directed pleural ribs (3 pairs of ribs in M. haitej). Trachidermus fasciatus is characterized with the most number of plesiomorphic features: the presence of branched rays in the pectoral fin, greater numbers of vertebrae, rays in the second dorsal, anal and pectoral fins, big anteanal distance and by number of preural vertebrae, supporting the procurrent rays. In C. koshewnikowi, the first dorsal fin occupies the most anterior position: aID 32.6–38.0% SL vs 35.7–38.7% SL in T. fasciatus and 36.4–40.8% SL in M. haitej.

A new species of Apterichtus (Anguilliformes: Ophichthidae) from the Marquesas Islands.

A new finless ophichthid eel, Apterichtus succinus sp. nov., is described based on a single specimen collected from the Marquesas Islands. The new species closely resembles A. klazingai Weber, 1913 in the shape and coloration of its head and its total vertebral count. The former differs from the latter in having more preopercular pores (4 vs. 3), fewer preanal vertebrae (54 vs. 56-63), a single tooth on the prevomer (generally absent), a shorter head (14.8 in TL vs. 12-14 in TL), and larger spots on its head and nape. Three species of Apterichtus (A. succinus, A. klazingai, and Apterichtus mysi McCosker & Hibino, 2015) are recognized from the Marquesas Islands.

A new species of Leptoderma Vaillant, 1886 (Osmeriformes: Alepocephalidae) from the Pacific coast of Central America.

A new species of Leptoderma Vaillant, 1886 is described from a single specimen trawled at 1368-1406 m depth off El Salvador, Central America, tropical eastern Pacific. Leptoderma ospesca n. sp. can be readily distinguished from its congeners by the following combination of characters: dermal papillae absent along the lateral line, pectoral-fin rays 6, pelvic-fin rays 5, pre-dorsal length 54.9% of SL, both dorsal and anal fins separated from the caudal fin, dorsal- and anal-fin rays long, procurrent caudal-fin rays numerous and extending far forward on caudal peduncle, caudal-fin rays 16, and total pre-ural vertebrae 60. A key to the species of the genus is presented.

Notes on the congrid eel genus Parabathymyrus from the western Pacific Ocean, with the description of a new species (Pisces: Anguilliformes: Congridae).

The congrid eel genus Parabathymyrus from the western Pacific Ocean is reviewed and three species are recognized: Parabathymyrus macrophthalmus from Japan, Taiwan, Vietnam and Australia, P. brachyrhynchus from Taiwan, Vietnam, the Philippines, Vanuatu and Solomon Islands, and a new species, P. philippinensis sp. nov., is described based on two specimens collected from the Philippines. These three species can be distinguished from each other by the number of total vertebrae (128-137 in P. macrophthalmus, 162-173 in P. brachyrhynchus and 140-141 in P. philippinensis sp. nov.), preanal vertebrae (39-46, 49-58, and 42), preanal lateral-line pores (36-44, 46-54, and 40-42), total lateral-line pores (121-131, 159-169, and 140-141) and supraorbital pores (4, 4 and 3).

A new species of moray eel (Anguilliformes: Muraenidae) from Taiwan, with comments on related elongate unpatterned species.

The following nine elongate unpatterned muraenid species of the subfamily Muraeninae, including one new species, are recognized from Taiwan and adjacent waters: Gymnothorax albimarginatus (Temminck & Schlegel), G. dorsalis Seale, G. melanosomatus Loh, Shao & Chen, G. phasmatodes (Smith), G. prolatus Sasaki & Amaoka, G. sagmacephalus Böhlke, Pseudechidna brummeri (Bleeker), Strophidon sathete (Hamilton) and G. pseudomelanosomatus new species, described from two specimens. This new moray eel is distinguished from its similar species, G. melanosomatus, by the following features: grey brown body (vs. black), snout length 20.5% (vs. 17.8%) of head length, smaller eye diameter 8.2% (vs. 10.0%) of head length; preanal length 49.5% (vs. 58.5%) total length, and preanal vertebrae 89-89 (vs. 105-109). Phylogenetic relationships of the nine species were examined using nucleotide sequence data from partial sequences of mitochondrial ND5 gene (600 bp), and seven species form COI (600 bp). The genetic analyses suggest that G. pseudomelanosomatus is distinct from G. melanosomatus and the other six species of Gymnothorax. Morphological features and mitogenetic affinities strongly suggest that "G." dorsalis should be placed in Strophidon rather than in Gymnothorax. The results also suggest that employment of ND5 and COI gene sequences are rather useful for identification of species and for obtaining reasonable insights into the phylogeny of the muraenid species.

Saurenchelys gigas sp. nov., a new nettastomatid eel (Teleostei, Anguilliformes, Nettastomatidae) from the western central Pacific.

Some large Saurenchelys specimens collected from Daxi, Yilan, NE Taiwan, and Da Nang, Vietnam, by bottom trawl at depths of 100-200 m, are described as Saurenchelys gigas new species. They differ from all known adult Saurenchelys species by predorsal length 40.9-46.8, head length 36.8-39.3in % of preanal length, 38-40 preanal vertebrae, 63-70 precaudal vertebrae, 38-42 preanal lateral-line pores, 56-63 preanal dorsal fin rays, and larger size (the maximum size 1155 mm TL).

A new species of Neenchelys (Anguilliformes: Ophichthidae: Myrophinae) from the eastern Indian Ocean.

A new worm eel, Neenchelys andamanensis, is described based on a single specimen collected from a depth of 520-531 m, Andaman Sea, eastern Indian Ocean. The new species is similar to N. daedalus, N. nudiceps, and N. similis in its total vertebral count and slender body, however, it differs from the latter three in having a shorter tail (60% TL vs. 70-76%), more numerous preanal vertebrae (77 vs. 59-71), and shorter pectoral fins (2.4% HL vs. 21-27%). Although the new species resembles N. mccoskeri in some proportional characters, the former species is distinguishable from the latter by its higher total vertebral count (221 vs. 172-184), position of the dorsal-fin origin (horizontal distance from the origin to a vertical through mid-anus 65% of trunk length vs. 46-59%) and width of the interorbital region (4.5% of head length vs. 8.2-16%). A revised key to the species of Neenchelys is provided.

An Eocene anchovy from Monte Bolca, Italy: The earliest known record for the family Engraulidae

AbstractEngraulids, also known as anchovies, are a distinctive group of clupeoid fishes characterized by a series of derived morphological features of the snout and infraorbital bones, suspensorium and branchial arches. Although anchovies are very abundant today, they are scarcely represented in the fossil record. A new genus and species of anchovy, †Eoengraulis fasoloigen. et sp. nov., is described from the Eocene (late Ypresian,c. 50 Ma) locality of Monte Bolca, Italy. It is based on a single well-preserved articulated skeleton that exhibits a unique combination of characters that supports its recognition as a new genus of the family Engraulidae, including: nine branchiostegal rays; 40 preural vertebrae and 17 pairs of pleural ribs; pleural ribs – preural vertebrae ratio 0.42; seven supraneurals; dorsal-fin origin at about mid-length of the body; about 16 dorsal-fin rays; anal-fin origin slightly behind the base of the last dorsal-fin ray; 19 anal-fin rays; seven pelvic-fin rays; and small needle-like pre-pelvic scutes. The morphological structure of the single available specimen suggests that †Eoengraulis fasoloiis the sister taxon of all other engrauline taxa. †Eoengraulis fasoloiis the oldest member of the family Engraulidae known to date. This taxon suggests that the earliest phases of diversification of engrauline anchovies probably occurred in the coastal palaeobiotopes of the western Tethys during Eocene time.

Phylogenetic position and tentative generic placement for Cyprinodon martae STEINDACHNER, 1875 (Teleostei: Cyprinodontiformes), a killifish from northern Colombia

Examination of photographs and a radiograph of the holotype of Cyprinodon martae, a rare killifish from coastal northern Colombia, revealed that it is not a rivulid by not exhibiting any diagnostic apomorphic condition of the Rivulidae, as well as the character states diagnosing the suborder Aplocheiloidei are not present. On the other hand, besides possessing many characters common among cyprinodontoids but not found among aplocheiloids, it has diagnostic features of the suborder Cyprinodontoidei, such as neural and hemal spines of the preural vertebrae 3 distinctively wider than those spines of the anterior vertebrae. These characters associated to the jaw dentition morphology unambiguously support its inclusion among the Cyprinodontidae, whereas the presence of an enlarged supraoccipital crest strongly suggests that is a member of the Caribbean killifish genus Cubanichthys.