Lobe Of Caudal Fin Research Articles

A New Gerreid Fish Species and Redescription of Gerres maldivensis Regan, 1902 from the Indian Ocean (Perciformes: Gerreidae)

Abstract A new gerreid fish species, Gerres mozambiquensis, is described on the basis of a holotype and one paratype from Larde Estuary, southern Nampura, Mozambique. The species is characterized by the following unique combination of characters: relatively deep body (greatest depth 46–47% SL); robust second anal-fin spine (greatest width of second spine/greatest width of third spine = 1.7–1.8); three supraneural bones configuration (0/0/0+2/); dorsal fin with nine spines and ten rays; lateral-line scales 43 or 44; 4 or 4½ scales between fifth dorsal-fin spine base and lateral line; caudal-fin lobes short, the tips rounded with growth; and six to eight indistinct dark vertical bars (bar width about half pupil diameter) on lateral surface of body. Gerres maldivensis Regan, 1902, formerly considered a junior synonym of G. erythrourus (Bloch, 1791) ( = G. abbreviatus), is reinstated as a valid Indo-Pacific species. It is characterized by body depth 43% SL, approximately eight faint dark vertical bars on b...

Nova espécie de Pimelodus (Siluriformes, Pimelodidae) dos rios Tapajós e Tocantins, Brasil

Pimelodus tetramerus sp. nov. difere das outras espécies de Pimelodus Lacepède por sua coloração típica, que consiste de quatro faixas escuras sobre os lados do corpo, a primeira, mais dorsal, iniciando logo após o final da placa pré-dorsal e terminando no final da base da nadadeira adiposa; a segunda, mais larga que a primeira, logo acima da linha lateral, percorre desde a borda lateral do processo supra-occipital até a base da nadadeira caudal. Ambas faixas estão fragmentadas em sua porção anterior, formando pontos escuros que, ocasionalmente, podem estar unidos, compondo um padrão vermiculado. Tais pontos escuros e/ou padrão vermiculado se distribui sobre a região pré-dorsal e cabeça. A terceira faixa, tão larga quanto a segunda, logo abaixo da linha lateral, inicia junto à região superior do processo pós-cleitral e estende-se até a base da nadadeira caudal e a quarta, de menor comprimento, podendo estar fraca ou ausente, inicia-se logo abaixo do processo pós-cleitral e finaliza até próximo à nadadeira pélvica. Além disso, constituem caracteres diagnósticos da nova espécie a presença de uma estreita faixa clara sobre a linha lateral, com aproximadamente 1/3 da largura da terceira faixa escura, e a presença de uma barra escura percorrendo longitudinalmente o lobo ventral da nadadeira caudal. A nova espécie compartilha o forâmen trigeminal tripartido com outras espécies de pimelodídeos.

The Genus Henonemus (siluriformes: Trichomycteridae) with a Description of a New Species from Venezuela

Abstract A new diagnosis for the trichomycterid genus Henonemus based on external characters is offered, and Henonemus triacanthopomus, new species, is described from the Orinoco River basin in Venezuela. The new species is distinguished from the other species of the genus by three or asymmetrically four opercular odontodes in specimens longer than 80 mm SL, a blackish ventral lobe of caudal fin, a row of mid-lateral dark blotches above the lateral line deflected dorsally on caudal peduncle, five interopercular odontodes inserted in the main series, and lower jaw teeth arranged in seven rows. Additionally we discuss the characters of external morphology that support monophyly of Henonemus, a less inclusive group within Stegophilinae comprising Acanthopoma, Apomatoceros, Henonemus, Megalocentor, Pareiodon, Parastegophilus, and Pseudostegophilus and a sister group relationship between Acanthopoma and Henonemus. Una nueva diagnosis para el genero tricomicterido Henonemus basada en caracteres externos es ofre...

Redescrição e osteologia de Bryconamericus exodon Eigenmann, 1907 (Ostariophysi, Characiformes, Characidae)

Apresenta-se a redescrição de Bryconamericus exodon Eigenmann (1907), espécie-tipo do gênero, uma descrição osteológica da espécie, uma comparação com outras espécies de Characiformes e comentários sobre seu relacionamento com outros caracídeos. Bryconamericus exodon é facilmente distinta de todas as demais espécies do gênero por possuir os lobos superior e inferior da nadadeira caudal castanho-escuros; aproxima-se das espécies de Bryconamericus com corpo alongado e baixo, menos de 30% do comprimento padrão, boca terminal e dentes da série externa do pré-maxilar desalinhados. Compartilha com outros Characidae um palatino fenestrado, perfurado ou adelgaçado, em sua porção médio-anterior, e um pós-cleitro 3 alongado e com aproximadamente a mesma largura em toda sua extensão, sinapomorfias adicionais para os Characidae com ii, 8 raios na nadadeira dorsal e quatro dentes na série interna do pré-maxilar.

New Species of Jupiaba (Characiformes: Characidae) from Rio Tiquié, Upper Rio Negro Basin, Brazil

Jupiaba poekotero, new species, is described from the Rio Tiquié, a tributary of the Rio Uaupés, in the upper Rio Negro system, estado do Amazonas, Brazil. It is distinguished from its congeners by the presence of an unpigmented, horizontally-oriented, roughly oval area on the proximal portion of the caudal-fin lobes, bordered posteriorly by dark pigmentation. Comments on the putative relationships of the new species are provided.

A new Stomatorhinus (Osteoglossomorpha: Mormyridae) from the Ivindo River, Gabon, West Central Africa

Stomatorhinus ivindoensis n. sp. is described from the basin of the Ivindo River, a tributary of the Ogooué River, in Gabon, West Central Africa. This species is characterized by its very small size which is not known to exceed 56 mm standard length. It is distinguished from S. fuliginosus from the Congo basin, the only described Stomatorhinus for which all members of the type series are within the size range of S. ivindoensis, by a smaller caudal peduncle depth to length ratio, a narrower head, a greater number of lateral line scales with visible tubes and pores and by rounded caudal fin lobes. It is distinguished from the similar S. polli, also from the Congo basin, by a longer snout, a smaller eye and a greater interorbital width relative to head length. It is distinguished from S. walkeri, the only other species described from the Ogooué River basin, by its smaller size, smaller snout to pectoral fin distance (relative to standard length) and by its reduced numbers of pectoral rays, vertebrae, and lateral line scales with visible tubes and pores. Stomatorhinus ivindoensis is endemic to the Ivindo River basin of Gabon and is allopatrically distributed with respect to S. walkeri which, although found elsewhere in the Ogooué River basin, has never been recorded from the Ivindo River. Stomatorhinus ivindoensis may be the smallest species of mormyrid fish yet described.Stomatorhinus ivindoensis n. sp. est décrite de la rivière Ivindo, un affluent du fleuve Ogooué, au Gabon, Afrique Centrale. Cette espèce est caractérisée par sa très petite taille, qui ne dépasse pas 56 mm en longueur standard. Elle se distingue de S. fuliginosus du bassin du Congo, la seule espèce de Stomatorhinus décrite dont l’intervalle de taille des spécimens types est compris dans celui de S. ivindoensis, par un rapport largeur sur longueur du pédoncule caudal plus petit, une tête plus étroite, un nombre d’écailles percées le long de la ligne latérale plus grand et une nageoire caudale aux lobes arrondies. Elle se distingue de S. polli, une autre espèce similaire du bassin du Congo, par un museau plus long, un oeil plus petit, et une distance interorbitale plus grande par rapport à la longueur de la tête. Elle se distingue de S. walkeri, la seule autre espèce de Stomatorhinus décrite du

New Knodus (Ostariophysi: Characiformes: Characidae) from the Upper Rio Paraguay Basin, Brazil

Abstract A new Knodus is described from the rio do Peixe, a tributary of the rio Cabacal, in the upper portions of the rio Paraguay basin in Mato Grosso state, Brazil. It can be distinguished from its congeners, and in fact from all remaining characid fishes, by the presence of two symmetric, large dark blotches basally on caudal fin lobes. Comments on the disputed recognition of the genus Knodus are provided.

Two new species of roughy (Trachichthyidae: Optivus) from coastal waters of southern Australia

Names are provided for two allopatric species of Optivus occurring in shelf waters of southeastern and southwestern Australia that have been treated in recent Australian literature. Optivus agastos n.sp., distributed from southern Queensland to central Victoria and northeastern Tasmania, and at Lord Howe Island, differs from the very similar O. elongatus, which is limited to New Zealand, in having fewer gill rakers (22-24, rarely 25, versus 25-27, rarely 24), slightly smaller eye, longer snout, and enlarged teeth along the inner margin of the premaxilla. Optivus agrammus n.sp., distributed from western South Australia to southwestern Western Australia, can be distinguished from congeners most readily by the lack of stripes on its caudal-fin lobes, curved dorsal outline of its nape and head in lateral profile, relatively deeper and shorter caudal peduncle, and lower dorsal and anal fins.

Hemiodus jatuarana, a new species of Hemiodontidae from the rio Trombetas, Amazon Basin, Brazil (Teleostei, Characiformes)

Hemiodus jatuarana, a new species of the Hemiodontidae from Oriximin , rio Trombetas, Amazon Basin, Brazil, is described. The new species can be readily distinguished from its congeners by the presence of a horizontally elongated dark spot on the caudal peduncle, and by the absence of any other dark pigmentation pattern on the body. Hemiodus jatuarana is readily separated from H. immaculatus, another species without dark pigmentation on the body, by having 25 27 epibranchial and 36 37 ceratobranchial gill rakers on the first branchial arch, and caudal-fin lobes without longitudinal stripes, vs. 14 16 and 21 25 gill rakers, and a conspicuous longitudinal stripe on each caudal-fin lobe in H. immaculatus. The new species is only known from its type-locality, where it cooccurs with H. immaculatus.

Moenkhausia bonita: A New Small Characin Fish from the Rio Paraguay Basin, Southwestern Brazil (Characiformes: Characidae)

Abstract Moenkhausia bonita, new species, is described from the Rio Baia Bonita, a tributary of the Rio Miranda, Rio Paraguay basin, Bonito, Mato Grosso do Sul, southwestern Brazil. The new species is distinguished from all congeners by the combination of the presence in alcohol-preserved specimens of a black midlateral stripe, a black posterior margin on each caudal fin lobe, the presence of a black lozenge-shaped blotch on the caudal peduncle that extends to the posterior limit of the median caudal fin rays, and the presence of seven gill rakers on the upper limb and 12 gill rakers on the lower limb of the first gill arch. Comments are included on the phylogenetic placement, ecology, and behavior of the species.

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.

A new subspecies, Polynemus melanochir dulcis , from Tonle Sap Lake, Cambodia, and redescription of P. m. melanochir Valenciennes in Cuvier and Valenciennes, 1831 with designation of a neotype

A poorly known threadfin, Polynemus melanochir Valenciennes in Cuvier and Valenciennes, 1831, is redescribed (as P. melanochir melanochir) on the basis of a newly designated neotype and a large number of specimens. Polynemus melanopus Sauvage, 1881 and 3 species commonly regarded as valid, Galeoides microps Steindachner, 1869, P. borneensis Bleeker, 1857, and Trichidion hilleri Fowler, 1905, are all considered junior synonyms of P. m. melanochir. In addition, a new subspecies, P. melanochir dulcis, is described on the basis of 3 specimens. Polynemus m. dulcis differs from P. m. melanochir in having a greater snout length [7% of SL vs. mean 6% (range 5–6%) of SL in the latter] and shorter upper caudal-fin lobe length [35% (34–35%) of SL vs. 39% (35–44%) of SL]. The former is currently known only from Tonle Sap Lake, Cambodia, whereas the latter is known from the Mekong River (Cambodia and southern Vietnam) and Kalimantan (=Borneo; Malaysia and Indonesia).

Gerres phaiya: A New Species of Gerreid Fish (Teleostei: Perciformes: Gerreidae) from India, with Comments on Gerres poieti and the Gerres erythrourus Complex

Two species of gerreid fishes have been confused under the name Gerres poieti Cuvier, 1829, a name originally assigned to the gerreid fish from Indonesia illustrated and named “ikan-poeti” in Renard, 1719. A year later, Cuvier published a description of Gerres poeti (incorrect subsequent spelling) based on a 150 mm SL fish from Mahé, southwest coast of India, which he stated was the same species as Renard's ikan poeti. Iwatsuki et al. recognized Renard's fish as Gerres longirostris (Lacepède, 1801); consequently, Gerres poieti Cuvier, 1829, becomes a synonym of G. longirostris. Despite several discrepancies between Cuvier's description of the Indian fish and Renard's illustration of ikan poeti, the name poieti (or poeti) has been used as the valid name for both G. longirostris and an undescribed species from the southwest coast of India. The Indian species misidentified as Gerres poeti (sic) by Cuvier in 1830 is here described as a new species, Gerres phaiya, of the Gerres erythrourus species complex. This new species is characterized by an exceptionally robust second anal fin spine (ratio of greatest width of second spine/greatest width of third spine = 1.5–2.4), three supraneural bones (0/0 0/2/), dorsal fin with nine spines and 10 rays, 36–40 lateral line scales, four or 4.5 scales between fifth dorsal fin spine base and lateral line, 12–15 total gill rakers on first gill arch, caudal fin lobes rounded posteriorly, body depth 46–52% SL, and the silvery body often with 6–10 dusky vertical bars. Additional data are given for G. erythrourus (Bloch, 1791).

Polydactylus bifurcus , a new species of threadfin from Lombok Island, Indonesia (Perciformes: Polynemidae)

Polydactylus bifurcus sp. nov. is described on the basis of a single specimen collected from Lombok Island, Indonesia. The new species is distinguished from all other Indo-Pacific Polydactylus species by the following combination of characters: 15 pectoral fin rays, 5 pectoral filaments, 69 pored lateral line scales, 30 gill rakers, second spine of first dorsal fin very strong and lateral line bifurcated on caudal fin base, extending to posterior margins of upper and lower caudal fin lobes.

Rabaulichthys suzukii , a new anthiine fish from Japan

Rabaulichthys suzukii is described as a new species of anthiine fish, family Serranidae, from three specimens collected in 5–15 m off the Izu Peninsula, Shizuoka Prefecture, Japan in February 1999 and February 2000. It represents the third species of the genus, the most characteristic feature of which is the very high dorsal fin of the male. R. suzukii is most closely related to R. altipinnis Allen from New Britain, differing in its larger size (to 64.2 mm SL, compared to 45.5 mm for R. altipinnis), higher dorsal fin (29.3% SL, compared to 26.2% for R. altipinnis), lack of a filament on the caudal-fin lobes, 19 pectoral rays (modally 20 in R. altipinnis), 9–10 + 23 gill rakers (8–9 + 21–22 in R. altipinnis), and in color. Because the Izu Peninsula collection sites have been heavily dived for many years, the recent appearance of R. suzukii is believed to the result of transport of postlarvae from a population to the south.

A new genus, Leptomelanosoma , for the polynemid fish previously known as Polydactylus indicus (Shaw, 1804) and a redescription of the species

A new genus, Leptomelanosoma, is proposed for the polynemid fish, Polydactylus indicus (Shaw, 1804). The genus differs from all other genera in the family Polynemidae by the following combination of characters: anterior one-third of lower jaw with small teeth extending onto lateral surface, adjacent portion of lip poorly developed; ethmoid not covered dorsally by frontals; sphenotics visible dorsally between anterior margins of parietal and pterotic; upper and lower caudal fin lobes very long, filamentous; swimbladder with many appendages inserted into lateral walls of abdominal cavity; grayish-black body. The type species, Polydactylus indicus, is redescribed as Leptomelanosoma indicum.

New Species ofGerresfrom the Southern Malay Peninsula, Belonging to theGerres setiferComplex (Perciformes: Gerreidae)

Gerres silaceus n. sp. is described from the holotype and two paratypes from the southern Malay Peninsula. The species is included as the fourth species in the “G. setifer complex” [G. chrysops Iwatsuki, Kimura and Yoshino, G. decacanthus (Bleeker), G. setifer (Hamilton), G. silaceus n. sp.], differing from all other congeners from the Indo-Pacific in having two supraneural bones and small size (less than 100 mm in standard length vs three supraneural bones and adults > 100 mm SL). The new species is further characterized by presence of IX, 10 dorsal fin rays, 34 or 35 lateral line scales, 3.5 scales between the 5th dorsal fin spine base and lateral line, caudal fin short (mean 29% of SL), slender second anal fin spine, pelvic fin ray with a wide white margin posteriorly, and a uniformly silvery ocher body. Gerres silaceus differs from G. setifer and G. decacanthus in body color, the last dorsal fin spine slightly shorter or similar length to the penultimate spine, higher gillraker counts and broadly rounded caudal fin lobes; it differs from G. chrysops in higher gillraker counts, rounded caudal fin lobe posterior margin and body color. The four species are generally distributed allopatically in the Indo-western Pacific.

Two new species of the cobitid genus Botia from the Lao Mekong basin

Two new cobitid species, Botia longidorsalis and B. caudipunctata, are described from the Lao Mekong basin. These species are fell into modesta-group of subgenus Hymenophysa in having short rostral and maxillary barbels, relatively large mental lobes, each with a pair of fleshy papillae at its anterior end, ordinary premaxillae not surrounding a cavity and a fontanelle on the top of the cranium. B. longidorsalis is the most similar to B. morleti, but is distinguishable from it and other species of modesta-group by the combination of the following characters : 9-10 branched dorsal fin rays, 30-31 total vertebrae, 13-18 narrow, irregular, brownish bars on the body sides, a broad, brownish bar on the caudal peduncle, and numerous small brownish spots on the caudal fin lobes. B. caudipunctata shows morphological similarities to B. lecontei and B. modesta, but differs from them and all other species by the combination of the following characters : 8 branched dorsal fin rays, 32-33 total vertebrae, brownish, saddle-shaped bands on the body behind the dorsal fin, a large, blurred blotch on the caudal peduncle, and pale dorsal, anal, pectoral and pelvic fins. The caudal fin has numerous small, brownish spots.

Description of a New Neolebias (Characiformes; Distichodontidae) from the Upper Zambezi Drainage of Zambia

A new distichodontid fish from small streams on the fringes of the Upper Zambezi River floodplain, Zambia, is described. Individuals of the new species, Neolebias lozii n. sp., are small (maximum 18.0 mm SL) and distinguished from all other members of the genus by a series of tall, black vertical bars along the flanks, short caudal peduncle, and broadly rounded, caudal-fin lobes. Neolebias lozii appears to be most closely related to Neolebias (=Dundocharax) bidentatus (Poll, 1967) from the Chicapa River drainage (Zaire basin) of northern Angola. In addition to its unique pigmentation pattern, Neolebias lozii differs from N. bidentatus in having a taller body, a shorter blunter snout, a shorter postorbital head length, shorter predorsal and preanal lengths, broader dorsal and anal fins, and broadly rounded instead of acutely angled caudal-fin lobes. The new species is the only southern African representative of the genus known to occur outside of the Zaire River system. SPECIES of the genus Neolebias Steindachner, 1894, are diminutive fishes of the African characiform family Distichodontidae (Teleostei, Characiformes) that inhabit small streams and swamps. According to Poll and Gosse (1963, 1982), the genus Neolebias contains eight nominal species. Based on a phylogenetic analysis of the Distichodontidae, Vari (1979) synonymized the genera Congocharax Matthes, 1964, and Dundocharax Poll, 1967 with Neolebias to eliminate polyphyletic taxa. Poll and Gosse (1982) challenged Vari's conclusion on the grounds that some skeletal and dentition characters were not given appropriate consideration in the analysis. Recently, Teugels and Roberts (1990) described an additional species, Neolebias powelli, from the Niger River delta. If we accept Vari's taxonomy, N. powelli brings the number of Neolebias species to 11. Here we describe a new species of Neolebias from the Upper Zambezi River drainage of Zambia's Western Province. Prior to this discovery, representatives of the genus were known only from the Zaire and Niger River basins. The new species appears to be most closely allied to Neolebias bidentatus from Angola, a species originally described by Poll (1967) as the sole member of the genus Dundocharax.

ThoracopterusBronn (Osteichthyes: Actinopterygii): A gliding fish from the Upper Triassic of Europe

ABSTRACT The Late Triassic gliding fishes of the genus Thoracopterus (Actinopterygii, Peltopleuriformes) are reviewed, and Thoracopterus martinisi, sp. nov. is described. We consider the family Thoracopteridae a valid taxon, but place it closer to Peltopleurus, rather than to Perleidus or Luganoia, especially on the basis of the pattern of skull roofing bones, shape of the preopercular, scale similarities, and caudal fin structure. Morphological characters of three species of Thoracopterus, such as length of paired fins, proportion of caudal fin lobes, and position of dorsal and anal fins, are compared with corresponding characters in extant monoplane and biplane gliding fishes. On the basis of this comparison, Thoracopterus is viewed as a biplane gliding fish, so far the only one known outside the extant “flying fishes” of the family Exocoetidae.