Preanal Vertebrae Research Articles

Comparative morphology, phylogeny, and classification of West African callopanchacine killifishes (Teleostei: Cyprinodontiformes: Nothobranchiidae)

A phylogenetic analysis combining 63 morphological characters and DNA sequences (3296 bp), comprising segments of the mitochondrial genes 16S and ND2, and the nuclear gene 28S, for 19 taxa of the West African killifish tribe Callopanchacini and 11 out-group taxa, highly supported the monophyly of the tribe, and made it possible to provide the first unambiguous diagnoses for the included genera (Archiaphyosemion, Callopanchax, Nimbapanchax, and Scriptaphyosemion). The monophyly of the Callopanchacini is supported by six morphological synapomorphies: posterior portion of the mandibular channel consisting of a single open groove; basihyal pentagonal, as a result of a nearly rectangular basihyal cartilage and a triangular bony support; dorsal process of the urohyal usually absent, sometimes rudimentary; presence of a wide bony flap adjacent to the proximal portion of the fourth ceratobranchial; a broad bony flap adjacent to the proximal portion of the fifth ceratobranchial; and haemal prezygapophysis of the pre-ural vertebra 2 ventrally directed. The analysis indicates that the medially continuous rostral neuromast channel, commonly used to diagnose the tribe, is plesiomorphic. This study also indicates that, among African aplocheiloids, the annual life cycle style developed once in Callopanchax, and then again independently in the clade containing Fundulopanchax and Nothobranchius. © 2015 The Linnean Society of London

A review of the glyptosternine catfish genus Exostoma Blyth 1860 from Thailand, with descriptions of two new species (Teleostei: Siluriformes).

We review members of the sisorid catfish genus Exostoma known from Thailand. Three species are recognized, of which two from the headwaters of the Chao Phraya River drainage in northwestern Thailand, are described here as new: E. effrenum and E. peregrinator. In addition to the two new species, E. berdmorei (which is here redescribed) is also known from the Salween River drainage in western Thailand. The three species can be distinguished from each other and other congeners by the morphologies of the adipose and caudal fins, as well as morphometric data for the eye diameter, head width, dorsal-to-adipose distance, body depth at anus, caudal-peduncle length, caudal-peduncle depth, and numbers of branched pectoral-fin rays and preanal vertebrae.

Early Development of the Caudal Fin Skeleton of Capelin,Mallotus villosus(Osmeridae)

Development of the caudal fin skeleton of capelin, Mallotus villosus, is described based on observations of cleared-and-stained specimens from a wild caught growth series ranging in size from 4.2 mm notochord length (NL) to 144 mm standard length (SL). The sequence of chondrification and ossification for each element is described and compared with that of related salmonoid and esocoid fishes. Caudal fin elements are first chondrified in specimens that are 8.9 mm NL and all elements are ossified by 52 mm SL. In general, hypaxial elements (e.g., parhypural, hypurals, hemal arches and spines of preural vertebrae) develop before epaxial elements (e.g., epurals, uroneurals, neural arches and spines of preural vertebrae). Preural centra are among the last elements to form in the caudal skeleton of M. villosus. Interestingly, preural centrum 1 does not form. The caudal fin skeleton morphology of adult M. villosus is nearly identical to that of other osmerid species, and the developmental sequence of the caudal s...

Eocene round herring (Teleostei: Clupeidae) from Monte Bolca, Italy

Fishes of the subfamily Dussumieriinae, also known as round herrings, are a small subgroup of the family Clupeidae inhabiting tropical and subtropical marine coastal waters. A new genus and species of round herring, Trollichthys bolcensis gen. et sp. nov., is described from the lower Eocene micritic limestone of Monte Bolca, northern Italy. This new clupeid taxon is based on seven partially complete articulated skeletons that exhibit a unique combination of features, including: two supramaxillae, edentulous jaw and palate bones, 41–42 preural vertebrae and 22–24 pleural ribs, pleural ribs-preural vertebrae ratio ranging 0.52–0.57, five or six supraneural bones, dorsal-fin origin located at about mid-length of the body, dorsal fin with about 16 rays, two postcleithra, pelvic-fin insertion slightly behind the dorsal-fin origin, and pelvic fin with eight rays. Trollichthys bolcensis shares several features with the extant round herring genus Spratelloides. However, because of its unique combination of featur...

Classification and relationships of Assiculus and Assiculoides (Teleostei: Pseudochromidae).

The monotypic Australian pseudochromid fish genera Assiculus and Assiculoides had been previously included in the subfamily Pseudochrominae on the basis of symplesiomorphic characters. Osteological synapomorphies are identified in support of a closer relationship to the remaining pseudochromid subfamilies. Two synapomorphies (five or fewer infraorbital bones, haemal spine of preural vertebra 2 attached to centrum) diagnose a clade consisting of Assiculoides, Pseudoplesiopinae, Anisochrominae and Congrogadinae. Two additional synapomorphies (parhypural not separate from hypurals 1+2, total caudalfin rays modally 27 or fewer) diagnose a more inclusive clade that also includes Assiculus. Two new subfamilies are erected to reflect these relationships.

Scolecenchelys fuscogularis (Anguilliformes: Ophichthidae, Myrophinae), a new worm eel from Japan

A new species of worm eel (Ophichthidae, subfamily Myrophinae), Scolecenchelys fuscogularis, is described from two specimens collected at 90–147 m depth off the coast of Japan. The new species is characterized by its dorsal-fin origin, which is located posterior to a vertical through the anus, its high total number of vertebrae (146–149), and its uniserial dentition on jaws and vomer. The new species is similar to Scolecenchelys australis and Scolecenchelys tasmaniensis in having 148–152 total and 60–61 preanal vertebrae and its uniserial teeth, but can be distinguished from the latter two species as it has a larger head [8.5–8.8 % of total length (TL) vs. 7.8–8.3 %], a longer trunk (39 % TL vs. 34–35 %), and a shorter tail (52–53 % TL vs. 56–58 %). Although S. fuscogularis most resembles Scolecenchelys chilensis in having 146–159 total and 59–64 preanal vertebrae and uniserial teeth, as well as in the proportions of the head, trunk and tail, the new species differs from the latter in having a smaller head (8.5–8.8 % TL vs. 8.9–9.7 %), a more slender body (body depth 1.5–1.6 % TL vs. 2.3–2.9 %), a more posterior dorsal-fin origin (horizontal distance between the origin and a vertical through the anus 83 % of head length vs. 36–54 %), no groove on the ventral side of its snout, and a dark lower jaw with a patch of melanophores on the ventral side of its branchial basket.

Alectrias markevichi sp. nov.—A new species of cockscombs (Perciformes: Stichaeidae: Alectriinae) from the sublittoral of the Sea of Japan and adjacent waters

A new species of cockscombs, Alectrias markevichi sp. nov., is described from 46 individuals from the sublittoral of Peter the Great Bay and Moneron Island (the Sea of Japan), South Kuril Strait, southern Hokkaido, and northeastern Honshu (the northwestern Pacific). A. markevichi sp. nov. differs from all the known species of the genus in the presence of only three pores in the occipital commissure (no pores near crest base and no medial tubule), only four pores in the preopercular canal, only one shortened spine at the end of dorsal fin, and 11–18 preural vertebrae with wide neural processes.

Effect of egg incubation temperature on the occurrence of skeletal deformities in Solea senegalensis

Summary Temperature is a factor known to have a marked influence on metabolism and consequently on development, inducing ontogenetic plasticity in fish larvae. In this study, three different temperatures (15, 18 and 21� C) were assayed during Solea senegalensis embryonic development prior to hatching. After hatching all larvae were reared at the same temperature (21.0 ± 0.1� C) until 30 days. We observed that lowering the incubation temperature from 21 to 15� C reduced the incidence of skeletal deformities from 80 to 60%. Intermediate incubation temperature (18� C), resulted in larvae that displayed a rate of abnormalities close to that observed at 15� C (64%). A similar typology of deformities was observed in fish from all rearing temperatures, with caudal vertebra being the most affected structures and with a low incidence of cranial and appendicular deformities. The effect of temperature in developmental plasticity will lead to osteological abnormalities mainly affecting the caudal vertebrae at 18� C (30%) and particularly the preural vertebra at 15� C (55%). Our results, clearly demonstrate a significant effect of water temperature during egg incubation on the skeletal development of Senegalese sole, indicating that 18� C is the most appropriated temperature. These findings highlight the importance of tightly controlling temperature regimes during the early development of S. senegalensis, and the need for optimizing rearing protocols in order to avoid skeletal disorders or impaired growth.

Gymnothorax melanosomatus, a new moray eel (Teleostei: Anguilliformes: Muraenidae) from southeastern Taiwan

Gymnothorax melanosomatus new species, is described here on the basis of eight specimens collected from eastern coastal Taiwan at a depth 50–180 m. This new moray eel is distinguished from a closely similar species, G. prolatus, by a combination of the following characters: a uniformly black body when fresh (vs. brown), a relatively long preanal length 58.5 % of TL (vs. 48.9), shorter snout length 17.8 % of HL (vs. 20.0), interobital width 12.2 % of HL (vs. 14.3); more preanal vertebrae 105–109 (vs. 74–86) and total vertebrae 201–211 (vs. 174–190). The male and female are not different in body color and pattern, but the numbers of median intermaxillary teeth are different between the sexes, 0 in male and 2–3 in female.

Gymnothorax melanosomatus, a new moray eel (Teleostei: Anguilliformes: Muraenidae) from southeastern Taiwan

Gymnothorax melanosomatus new species, is described here on the basis of eight specimens collected from eastern coastal Taiwan at a depth 50–180 m. This new moray eel is distinguished from a closely similar species, G. prolatus, by a combination of the following characters: a uniformly black body when fresh (vs. brown), a relatively long preanal length 58.5 % of TL (vs. 48.9), shorter snout length 17.8 % of HL (vs. 20.0), interobital width 12.2 % of HL (vs. 14.3); more preanal vertebrae 105–109 (vs. 74–86) and total vertebrae 201–211 (vs. 174–190). The male and female are not different in body color and pattern, but the numbers of median intermaxillary teeth are different between the sexes, 0 in male and 2–3 in female.

Matanui, a new genus of deepwater triplefin fishes (Pisces: Tripterygiidae) from New Zealand

Matanui new genus is proposed for two New Zealand species, Forsterygion bathytaton Hardy, 1989 and F. profundum Fricke and Roberts, 1994, which are redescribed. Matanui differs uniquely from other tripterygiid genera in having lateral line scales with a notch at the upper posterior corner, two procurrent rays between the posterior epural and 5th hypural bone (HU5), one procurrent ray anterior to haemal spine of the 3rd preural vertebra (PU3), dorsal fin formula IV‐ 1N‐0–1 ‐0–1, pterygiophores of the first three segmented anal fin rays anterior to the haemal spine of the first caudal vertebra, the urohyal triangular ventrally with a narrow posterior end, suborbital sensory canal not extending over premaxilla, supratemporal canals not meeting mid‐dorsally, and large sensory pores. The genus is endemic to New Zealand, occurring in continental shelf waters from 12 to 550 m.

Description and familial allocation of the African fluvial genus Teleogramma to the Cichlidae

The external morphology, osteology, and myology of the African fluvial genus Teleogramma are described, and its familial allocation is discussed. Teleogramma is included in the family Cichlidae by loss of a major structural association between adductor mandibulae sections 2 and w, and by having an insertion of a large ventral division of adductor mandibulae section 2 onto the anguloarticular, expanded head of the fourth epibranchial, transversus dorsalis subdivided into four parts, functionally decoupled premaxillae and maxillae, the stomach's extendible blind pouch, the left-hand exit to the anterior intestine, the first intestinal loop at the left side, two epurals, seven branched rays on each upper and lower caudal fin lobe, free first uroneural from a united element of first preural and ural vertebra, and third preural vertebra fused with its haemal spine. Seven synapomorphies supporting the monophyly of Teleogramma are indicated, including the absence of or very low supraoccipital crest, the presence of a nostril tube, nonextended supraoccipital anteriorly, absence of extensive cartilaginous cap on the anterior border of the second epibranchial, presence of a beaklike projection on the cleithrum, caudal branched slip of epaxialis that inserts onto the upper two or three branched rays on the upper lobe of the caudal fin, and flexor dorsalis superior, which inserts onto the lower four unbranched rays on the upper lobe of the caudal fin.

The hemiramphid,Oxyporhamphus, is a flyingfish (exocoetidae)

Osteological and myological studies on the caudal complex of flying fishes (Exocoetidae) plusOxyporhamphus (of Hemiramphidae) revealed the following shared derived conditions: 1) neural spines of preural vertebrae broader than haemal spines; 2) spur present on posterior margin of preural vertebra 2;3) upper hypural plates steeply angled; 4) lower hypural plate extending strongly posteriorly; 5) lower hypural plate deeply surrounded by caudal fin rays; 6) flexor ventralis well developed, arising from neural spines; 7) flexor ventralis externus well developed; 8) adductor dorsalis well developed.Oxyporhamphus and exocoetids also share a lower jaw of adults not elongate and the premaxilla with a straight anterior margin. Therefore,Oxyporhamphus is transferred to the Exocoetidae, with which it shares a total of 10 derived conditions.

Dysomma opisthoproctus, a New Synaphobranchid Eel (Pisces: Synaphobranchidae) from the Northeastern Coast of Taiwan

A new species of synaphobranchid eel, Dysomma opisthoproctus, is described on the basis of a single specimen from the northeastern coast of Taiwan at depth about 200 m. It is characterized by a posteriorly positioned anus (1.5 times head length behind pectoral-fin base), well-developed cheek papillae, seven or eight compound dentary teeth, four compound vomerine teeth, four infraorbital pores, three supraorbital pores, seven preoperculomandibular pores, and 120 vertebrae (35 preanal vertebrae).

First Indo-Pacific Record of the Eel Family Myrocongridae, with the Description of a New Species of Myroconger

An eel collected in 640-320 m on the Kyushu-Palau Ridge, western North Pacific, and described as Myroconger gracilis n. sp., is referred to the Myrocongridae. This is the first record of the family outside the Atlantic where it has been known for more than a century from just one complete specimen of M. compressus Giinther collected at St. Helena. The new species is distinct from M. compressus in being more slender-bodied, with shorter head and predorsal, more prominent teeth and more preanal, precaudal and total vertebrae.

New species of Enchodus (Pisces: Enchodontoidei) from the lower Cenomanian of Ein-Yabrud, Israel

A new species, Enchodus brevis (Enchodontoidei: Enchodontidae), is described from lower Cenomanian beds in Ein-Yabrud, near Jerusalem. The species is characterized by the following features: the shortest enchodontid body; an ectopterygoid bearing one smooth canine terminal tooth; barbed dentary teeth; a huge front tooth of dentary with two anterior cutting edges; two supraneurals; second preural vertebra without a neural spine; and absence of lateral line scales except for a long hook-like terminal scale at the caudal peduncle. The systematic position of the new species suggests the emendment of the generic diagnosis.