Preanal Vertebrae Research Articles

Parauchenoglanis stiassnyae (Siluriformes: Auchenoglanididae): A new species of giraffe catfish from Mfimi-Lukenie basin, central Africa, Democratic Republic of Congo.

A new, distinctively short-bodied giraffe catfish of Parauchenoglanis is described from the Ndzaa River, a small left-bank tributary of the Mfimi-Lukenie basin in the Central basin of the Congo River in the Democratic Republic of the Congo. The new species can be distinguished from all congeners by having 29 or fewer (vs. 33 or more) total vertebrae. It can further be distinguished from all congeners, except Parauchenoglanis zebratus Sithole et al., 2023 and Parauchenoglanis ngamensis (Boulenger 1911), by having 13 or 14 (vs. 16 or more) pre-anal vertebrae. The species is endemic to the Mfimi River basin, where it has been collected mainly in blackwater tributaries.

A new method for regionalization of the vertebral column in salmonids based on radiographic hallmarks.

Current procedures to establish vertebral column regionalization (e.g., histology) in fish are time consuming and difficult to apply. The aim of this study was to develop a more rapid and accurate radiology-based method for Atlantic salmon (Salmo salar). A detailed analysis of 90 animals (4 kg) led to the establishment of region-specific radiographic hallmarks. To elucidate its transferability to other salmonid species, radiography was carried out in brown trout (Salmo trutta), Arctic char (Salvelinus alpinus), rainbow trout (Oncorhynchus mykiss), pink salmon (Oncorhynchus gorbuscha), and Chinook salmon (Oncorhynchus tshawytscha). This method was also evaluated for whole ungutted fish. The vertebral column of Atlantic salmon can be subdivided into five regions (R1-R5) based on anatomy: postcranial (R1, V1, and V2), abdominal (R2, V3-V26), transitional (R3, V27-V36), caudal (R4, V37-V53), and ural (R5, V54-V59). The following specific radiographic hallmarks allow the identification of regions: (i) lack of ribs in R1, (ii) modified parapophysis of the first vertebra of R3, (iii) prominent hemal spine of the first vertebra of R4, and (iv) the separated hemal spine of the most cranial pre-ural vertebra of R5. These hallmarks were all transferable to the other salmonid species assessed. The results include a further description of various region-specific characteristics in Atlantic salmon. The method was found applicable for sedated/whole ungutted fish, verifying it as quick and easy compared to other regionalization methods. The regions defined by radiology in this study agree with the vertebral column regions recently defined for Chinook salmon (O. tshawytscha). Thus, and considering the results of this study on various salmonid species, the currently developed regionalization protocol can be generally used for salmonids.

Pathological caudal skeleton of an ichthyodectiform fish from the Upper Cretaceous Niobrara Formation of western Kansas, USA.

A series of 12 contiguous caudal vertebrae of an ichthyodectiform fish from the Smoky Hill Chalk Member of the Niobrara Formation is described. The vertebral centra exhibit extensive overgrowth of pathological bone and there is additional pathological bone within the centra and intervertebral spaces, which together resulted in the coossification of most centra. The extent of the pathology is greatest on preural vertebrae 1-3 and decreases anteriorly, which suggests that the pathology began posteriorly and progressed anteriorly. In addition to the pathological overgrowth on bones, the specimen preserves features interpreted as calcified and/or ossified soft tissues associated with the neural and haemal canals. The pathologies are unlike previously described examples of bony pathologies in fish, and it is suggested that they resulted from combined bacterial and fungal infections. As the pathologies developed, they would have adversely impacted the fish's swimming and feeding abilities, and presumably eventually led to the fish's death.

Two new species of the congrid eel genus Ariosoma (Anguilliformes, Congridae, Bathymyrinae) from Indian waters

Two new species have been described from Indian waters, based on the materials collected from Kochi coast, Arabian Sea, Gulf of Mannar and West Bengal coast along the Bay of Bengal. Ariosoma gracilesp. nov. is described, based on five specimens collected from the landings at Kalamukku Fishing Harbour, Arabian Sea. The new species is characterised by longer tail, 55.3–58.7% TL; dorsal-fin origin above pectoral-fin base; no dark or whitish bands on dorsal surface of head, ventral extremities of lower jaw and mid-portion with minute dark pigmentation patch; anus positioned well before the middle of total length; SO canal with 4 pores; 0 or 3 pores on ST canal; pre-dorsal vertebrae 9; pre-anal vertebrae 49–54; total vertebrae 140–142. Ariosoma gracilesp. nov. is closely related to Ariosoma dolichopterum and Ariosoma emmae by sharing similar morphometrics and pre-anal vertebral counts. However, it differs by having more total pores (132–135 vs. 121–129 in A. dolichopterum, 123–126 in A. emmae); fewer pre-anal pores (43–46 vs. 47–51 in A. dolichopterum, 50–53 in A. emmae); more pre-dorsal pores (9 vs. 5–9 in A. dolichopterum, 4–6 in A. emmae). Another new species, Ariosoma kannanisp. nov. is described on the basis of two specimens (157–171 mm TL) from Gulf of Mannar and one specimen (201 mm TL) collected from Shankarpur Fish Landing Centre, West Bengal. This species is similar to Ariosoma megalops, but readily differs by having smaller eyes, smaller interorbital distance and exhibits 10.8% genetic divergence from A. megalops from the Taiwan waters.

Discovery of a new Muraenichthys eel (Anguilliformes: Ophichthidae) from the Bay of Bengal, India, with its molecular characterization

Muraenichthys hibinoi sp. nov. is described herein based on two specimens collected from Shankarpur fishing harbor, West Bengal, India. The new species differs from Muraenichthys gymnopterus, Muraenichthys hattae, Muraenichthys longirostris, and Muraenichthys thompsoni by having less distance between the anus and the origin of the dorsal fin (61.8%–57.37% vs 73.8%–82% of HL). The new species has a close morphological affinity with M. gymnopterus and M. hattae with significant differences from both species. The new species differs from M. gymnopterus by having higher vertebral count, i.e., predorsal vertebrae (40– 41 vs 30), preanal vertebrae (50 vs 43), and total vertebrae (140–141 vs 130). The new species also differs from M. hattae, having fewer total vertebrae (141–142 vs 148–155) and fewer predorsal vertebrae (40–41 vs 48–53). The COI gene sequence of the new species has been generated and submitted to the NCBI database with accession number OP114397. The new species differs from all the available congeneric sequences of Myrophinae group available in NCBI or BOLD with K2P distances of 8.4% to 9.5%. Thus, both the genetic and morphometric data confirm the presence of a new species in Myrophinae from Indian waters.

A new deep-water conger eel of the genus Rhynchoconger (Anguilliformes: Congridae) from the southwest coast of India, Arabian Sea.

A new species of deep-water conger eel, Rhynchoconger bicoloratus sp. nov., is described herein based on three specimens collected from the deep-sea trawlers landing at Kalamukku fishing harbour, off Kochi, Arabian Sea, from a depth beyond 200 m. The new species is distinguished from its congeners by having the following combination of characters: head larger than trunk, rictus at posterior margin of pupil, dorsal fin origin slightly before the pectoral fin insertion, eye diameter 1.7-1.9 in snout, ethmovomerine teeth patch broader than long with 41-44 recurved pointed teeth in 6-7 rows, vomerine teeth patch pentagonal shaped with single tooth on posterior end, pre-anal vertebrae 35, body bicoloured, peritoneum and stomach black. Genetically, the new species differs from its congeners with a divergence of 12.9-20.1% in the mitochondrial COI gene.

A new short brown unpatterned moray eel (Anguilliformes, Muraenidae) from the southeast coast of India, Bay of Bengal

Gymnothorax tamilnaduensissp. nov., a new species of short brown unpatterned moray, is described, based on four specimens ranging from 272–487 mm total length collected from the trawl bycatch landings at Mudasalodai fish landing centre, off Cuddalore coast, Tamil Nadu, southeast coast of India. The new species is distinguished by the following combination of characters: origin of dorsal fin at middle of rictus and gill opening, anus just before mid-body, series of lines of small dark spots present on head and a single line of black spot-on mid-line of body, jaw pores with white rim, anal-fin margin whitish, 3 pre-dorsal vertebrae, 56–59 pre-anal vertebrae and 139–150 total vertebrae. The new species differs from its known Indian water congeners by having series of lines of small dark spots present on the head and a single line of black spots on the mid-line of the body (vs. absent in all the three congeners in India), serrated teeth (vs. smooth), jaw pores with white rim (vs. black to brown in others) and higher vertebral count (139–150 vs. 134–138 in others). Our morphological and molecular analyses show that the new species forms a distinct clade from its congeners and these data support the status as a new species.

Additional Data on Arctozenus australis Ho et Duhamel, 2019 (Pisces: Aulopiformes, Paralepididae) off Kerguelen Islands

This work clarifies the morphological data for the recently described species Arctozenus australis Ho et Duhamel, 2019. Specimens caught in the northwest of the known range of the species confirm the validity of diagnostic characters and expand the known range of the following parameters: predorsal length, prepelvic length, preanal length, distance between origins of dorsal and anal fins, head depth, distance between origins of dorsal and pelvic fins, interorbital width, caudal-peduncle depth, snout length, upper-jaw length, lower jaw, number of caudal vertebrae, preanal vertebrae, and anal fin rays.

A new congrid eel, Rhynchoconger randalli sp. nov. (Congridae: Anguilliformes), with a pentagonal pattern of vomer dentition from the Bay of Bengal, Indian waters.

A new species Rhynchoconger randalli sp. nov. is described herein on the basis of 2 specimens collected from Paradeep fishing harbor, Odisha, India along the Bay of Bengal from a depth of about 3640 meters. The pentagonal vomerine teeth pattern is unique among all the Rhynchoconger species described to date. The new species is characterized by predorsal vertebrae 78 and preanal vertebrae 2931. The new species closely resembles the recently described Rhynchoconger smithi, but differs in having a larger eye diameter (12.512.9% HL vs. 9.59.7% in R. smithi), smaller interorbital space (13.113.5% HL vs. 15.018.1 in R. smithi), lower dorsal-fin ray count before vent 4447 vs. 5458 in R. smithi, and unique pentagonal vomerine teeth pattern.

A new species of conger eel, Ariosoma (Congridae: Bathymyrinae), from the Bay of Bengal, India.

Ariosoma bengalense sp. nov. is described on the basis of two specimens having total length (TL) 216304 mm, collected from the northern part of the Bay of Bengal, India. The new species is characterized by the dorsal-fin origin positioned above the gill-opening margin and above the 9th lateral-line pores, supratemporal pore absent, 910 predorsal vertebrae; 4649 preanal vertebrae and 146149 total vertebrae. The new species most closely resembles the Indian species Ariosoma gnanadossi, the new species differs from A. gnanadossi having the snout length (SL) longer than eye diameter (snout length 1.42.0 in eye diameter) vs. snout length almost equal to the eye diameter in A. gnanadossi. Further, the new species has translucent pectoral fins vs. black pectoral fins in Ariosoma gnanadossi. The new species differs from four of the seven species reported from India: Ariosoma majus, A. melanospilos, A. maurostigma and A. indicum with absence of supratemporal pores vs. three in all the species mentioned.

A new species of the congrid eel genus Ariosoma (Anguilliformes: Congridae) from the south-west coast of India.

A new congrid eel species, Ariosoma maurostigma sp. nov., is described on the basis of 24 specimens collected from the deep-sea trawl by-catch, Kalamukku Fishing Harbour, off Kerala, Arabian Sea. The new species differs from all other congeners in having the following combination of characters: dark mark or spot on the posterodorsal margin of the eyes; dorsal surface of head with two faint darkish bands across the anterior and posterior margin of the eye; origin of the dorsal fin before the pectoral-fin base; short vomerine teeth patch, ST pores 3, 1 median pore and 1 lateral pore on each side just behind the median pore; preanal vertebrae 47-51; precaudal vertebrae 54-57; total vertebrae 136-142; total pores 129-134. The phylogenetic analysis reveals that the new species is closely related to Ariosoma melanospilos and Ariosoma anale, with divergences of 13.8% and 14.9%, respectively.

Development and malformations of the vertebra in the early stages of starry flounder Platichthys stellatus

The purpose of this study was to analyse the normal vertebral development and the status of malformations for Platichthys stellatus fed in artificial conditions. Eggs were taken from cultured parental P. stellatus, being incubated until larvae, juvenile in an artificial recirculating system. Specimens that were randomly collected from hatching to 75-day-old were dyed with alcian blue and alizarin red. Vertebral development as cartilage was initiated at 6-day-old by the emergence of the anterior haemal arches and spines in the haemal region, followed by the neural arches and spines. The vertebral centra were visible at 10-day-old. The initial ossification events happened on the exterior border surrounding the vertebral centra where the haemal and neural arches connected to the vertebral centra in the front of the haemal region at 14-day-old. The parapophysis firstly formed in the most posterior prehaemal region at 16-day-old. All parts of vertebral column were ossified at 30-day-old, except for the haemal and neural spines from preural vertebrae until the end of the experiment. The total vertebral numbers were no significant differences from Stage 3 to Stage 5. The observed skeletal malformations were classified into 22 types. Among all specimens analysed, 62.9% of the ones presented malformation in the skeleton. From these, 27.3% of the specimens showed only one malformation, and 35.5% revealed multiple malformations. The frequencies of malformations were increasing from Stage 2 to Stage 5 with the highest value of 66%.

Coloconger maculatus sp. nov., a species of short-tail eel from eastern Taiwan (Anguilliformes: Colocongridae).

A new species of Coloconger is described from a large female collected off eastern Taiwan. It can be distinguished from congeners by having a large black blotch on rear portion of tail; posterior end of tail white; and combination of characters: head small 15.7% TL; 4 supratemporal pores, middle 2 in pair; 7 supraorbital pores, 2 pores over posterior nostril; 12 or 14 infraorbital pores; 14 preoperculomandibular pores; 226 dorsal-fin rays and 122 anal-fin rays; preanal vertebrae 77 and total vertebrae 145; rictus through a vertical of posterior margin of pupil; snout shorter than eye diameter; distance between origins of pectoral and dorsal fins 69.4% pectoral-fin length; and body brownish gray dorsally, light gray ventrally, and dorsal fin dark gray. Data and variations of Coloconger japonicus found in Taiwan are provided and discussed.

A new species of the genus Cirrhimuraena (Anguilliformes: Ophichthidae) from the Bay of Bengal, India.

A new species of the genus Cirrhimuraena (Anguilliformes: Ophichthidae), Cirrhimuraena indica sp. nov., is described based on eight specimens collected from the Paradip (Odisha) and Petuaghat harbours (West Bengal) along the Bay of Bengal. The species is distinct in having the upper jaw fringed with 16-17 cirri before posterior nostril and 4-5 in between the anterior and posterior nostrils on the side; dorsal fin originates above the level of gill opening, predorsal length is 9.3-10.9 in total length; the head is relatively large, the length is 9.3-9.8 in total length; no infraorbital pores are observed between the nostrils; teeth are numerous, small, conical and in bands on each jaw; pores are present before the gill opening 10-11 and before anus 47-48; pectoral-fin length is 2.4-2.8 in head length; predorsal vertebrae are 8-10, pre-anal vertebrae 43-47 and total vertebrae 164-169. In the maximum likelihood tree analysis for COI gene, the new species belongs to the same clade as the other congener of Cirrhimuraena chinensis and is separated from the species morphologically and genetically.

A new deep-water species of snake eel, Xyrias anjaalai sp. nov. (Anguilliformes: Ophichthidae), from the Western Indian Ocean.

A new species of snake eel Xyrias anjaalai sp. nov. (Anguilliformes: Ophichthidae) is described from morphological analysis of 12 specimens and molecular analysis of four specimens, caught off Kollam, Kerala, southwestern India, by deep-sea trawling. X. anjaalai is distinguished from its congeners by having a large eye diameter, a short snout, a different dentition pattern as in the 3rd row of maxillary teeth beginning at the level of the 4th vomerine tooth between the two existing rows in the inner series of maxillary teeth, an irregular tooth patch for approximately 1/10th of the lateral side of the dental arch in the distal portion and a vertebral count of predorsal vertebrae 18-21, preanal vertebrae 73-76 and total vertebrae 147-149. Phylogenetic relationships of X. anjaalai with other species in Ophichthidae were examined using partial nucleotide sequences of the COI gene (617 bp). The genetic analyses suggest that the new species is closest to X. revulsus followed by Apterichtus klazingai with Kimura 2 parameter (K2P) values of 0.6 and 2.8% respectively. In the phylogenetic reconstruction, sequences of X. anjaalai formed a distinct clade demonstrating their uniqueness as a separate species.

Osteology of the posterior vertebral column and caudal skeleton of marine amphibious gobies (mudskippers) (Teleostei: Gobioidei)

Mudskippers are amphibious gobies (Teleostei: Gobioidei, Oxudercinae) that have served as models for the specialised physiology and behaviour of fishes out of water. In this study, a comparative analysis of the posterior vertebral column and the caudal skeleton of ten mudskipper species was conducted on the basis of X-ray imaging. The species considered were Apocryptes bato, Apocryptodon madurensis, Boleophthalmus dussumieri, Oxuderces dentatus, Periophthalmodon freycineti, Pn. schlosseri, Periophthalmus novemradiatus, Ps. waltoni, Pseudapocryptes borneensis, and Scartelaos tenuis. For the osteological description the new term 'modified caudal vertebra' is used for all those vertebrae that display visibly modified neural and/or haemal spines compared to the spines of a 'usual' caudal vertebra, but are not involved in the support of caudal rays. The results reveal that the most terrestrial forms (Pn. freycineti, Pn. schlosseri, Ps. novemradiatus, Ps. waltoni) possess distinct traits that are seldom found in the other species. Among these features are (a) the existence of at least two modified caudal vertebrae (also present in S. tenuis), (b) a particularly close, dovetailing association between the neural spines of the preural vertebrae two and three (restricted to Ps. novemradiatus and Ps. waltoni), and (c) thickening and shortening of the ventralmost principal caudal rays (also present in B. dussumieri and S. tenuis). These findings support the idea that the posterior caudal vertebrae and caudal skeleton of the mentioned species are modified to enhance locomotion on land. Moreover, a relationship between character development and degree of terrestrial adaptation is probable, as all three traits are most pronounced in Ps. waltoni, which correlates with its strikingly high level of adaptation to amphibious life. A further aspect of this study is that the newly recognized skeletal structures have good fossilization potential and could therefore facilitate recognition of fossil species of mudskippers, which are currently unknown.

Resurrection of Ophichthus zophistius (Actinopterygii: Anguilliformes: Ophichthidae), with a revised diagnosis of O. altipennis.

Pisoodonophis zophistius Jordan and Snyder 1901 is redescribed as a valid species of Ophichthus Ahl 1789 based on 46 specimens including the holotype. Although this name has been synonymized under Ophichthus altipennis (Kaup 1856), the former can be distinguished from the latter by a relatively acute snout (vs. strongly acute), presence of irregular obscure bars on the body (vs. bars absent), 11-13 predorsal and 61-63 preanal vertebrae (vs. 8-9 and 52-58, respectively) and 10-14 predorsal and 59-64 preanal lateral-line pores (vs. 7-9 and 55-61, respectively), dorsal-fin origin usually above or behind the pectoral-fin insertion (vs. anterior to the insertion), and tail broad and tapered slowly (vs. becoming slender and tapered rapidly). Furthermore, Ophichthys intermedius Regan 1905 and Microdonophis fasciatus Chu, Wu and Jin 1981 are junior synonyms of O. zophistius, and Ophichthus melanochir Bleeker 1864 is that of O. altipennis.

New Moray Eel Species of Strophidon genus (Muraenidae) from Vietnam

A new species, Strophidon dawydoffi sp. n., from Nha Trang Bay (South China Sea, Vietnam) was described. The new species is well distinguished from the cooccurring S. sathete species by a thinner and elongated body, tail lobiform-extended at the end, external absence of vertical fins, a much smaller number of preanal vertebrae, elongated vertebral centra in the middle portion of the caudal region of the vertebral column, the structure of neural arches and parapophyses, variegated coloring of the body and oral cavity, a larger number of teeth in the inner rows on maxillare and dentale, and two or three rows of papillae on the lips. Differences in the number of infraorbital pores and in the shape of the snout between S. sathete specimens are associated with individual variability.

Ophichthus kailashchandrai sp. nov. (Anguilliformes: Ophichthidae): a new species of snake eel from Indian waters, Bay of Bengal.

A new snake eel (Anguilliformes: Ophichthidae: Ophichthinae) species, Ophichthus kailashchandrai sp. nov., is described from three specimens, collected from the Shankarpur fishing harbour located on the northern part of the Bay of Bengal, West Bengal, India. Ophichthus kailashchandrai sp. nov. is distinguished from its congeners by having its dorsal-fin origin at the posterior third of the pectoral fin, preanal length 2.6-2.8 in TL, uniserial maxillary and mandibular teeth and vertebral count (predorsal vertebrae 14-15, preanal vertebrae 54-55, and total vertebrae 180-182).

A new record of congrid eel, <i>Bathycongrus bleekeri</i> (Congridae) from Vietnam

Three specimens of Bathycongrus bleekeri were collected during the survey in 2015 and 2017. The newly recorded species is described herein, a small, moderately elongate species of Bathycongrus with head and body compressed; vertical fins without black mark; tail slender, attenuated, but not filiform; trunk length 1.2 times greater than head length; teeth small, conical, in about three-four rows on jaws, in a small triangular patch on vomer; 28–29 preanal vertebrae, total of 111–113 vertebrae; 26–28 preanal lateral-line pores. Additional data on the morphology and distribution of the species increases the total number of known species in the family Congridae in Vietnamese waters to twelve.