RESUMO
The family Myrocongridae comprises some of the rarest and least known benthopelagic eel species. It is composed of a single genus, Myroconger Günther, 1870, and five valid species: M. compressus Günther, 1870, from the Atlantic Ocean; M. gracilis Castle, 1991, M. prolixus Castle Béarez, 1995, and M. nigrodentatus Castle Béarez, 1995, from the Pacific Ocean; and M. seychellensis Karmovskaya, 2006, from the Indian Ocean. Herein, we report on an additional species from the Atlantic Ocean, Myroconger pietschi n. sp., based on a specimen obtained on the Aracati Bank, North Brazilian ridge, off Ceará State, western South Atlantic. Myroconger pietschi can be diagnosed by having 190 anal-fin rays, a short pectoral fin (16.6% HL), the posterior portion of the ethmovomerine teeth arranged in a single row, teeth on lower and upper pharyngeal tooth plate 24 and 27, and 10 branchiostegal rays.
Assuntos
Enguias/anatomia & histologia , Enguias/classificação , Animais , Oceano Atlântico , BrasilRESUMO
A new species of Characidium Reinhardt, 1867 endemic to tributaries of the upper rio Paraguaçu in the Chapada Diamantina, Bahia, Brazil, is described. The new species can be distinguished from its congeners except C. bahiense, C. bimaculatum, C. laterale, C. nana, C. nupelia, and C. xavante, by having a conspicuous peduncular blotch in addition to the basicaudal spot on the base of the middle caudal-fin rays. Among other features, the new species differs from C. bahiense, C. laterale, C. nana, C. nupelia, and C. xavante by having a complete lateral line with 32-36 perforated scales (vs. lateral line short, with 9-11 perforated scales), and from C. bimaculatum by the body pigmentation pattern, with secondary bars present (vs. absent), total bars 11-16 (vs. 10-12), peduncular blotch rounded (vs. horizontally elongated), and mature males not having a darker dorsal fin (vs. proximal third of dorsal fin darker in mature males). Characidium bimaculatum, a poorly known species from Northeastern Brazil, is redescribed.
Assuntos
Caraciformes/anatomia & histologia , Caraciformes/classificação , Animais , Brasil , Feminino , Masculino , Especificidade da EspécieRESUMO
A new species of Corydoras is described from tributaries of the rio Arinos, rio Teles Pires and rio Preto, all in the rio Tapajós basin. The new species is a member of a group that includes 36 species with spots on the body. Within this group, the new species can be readily distinguished by having a smaller dorsal-fin spine than the first three subsequent soft dorsal-fin rays; pectoral, pelvic and anal fins hyaline; dorsal-fin interradial membrane hyaline; rounded spots on trunk restricted to dorsolateral body plates and dorsal portion of ventrolateral body plates, not reaching the base of pelvic and anal fins. The new species can be further distinguished from Corydoras xinguensis by having spots with diffuse edges, and from all other species of spotted Corydoras except C. multimaculatus, by the absence of ventral platelets. A phylogenetic analysis recovered the new species plus Corydoras metae and C. araguaiensis in a clade sharing the presence of a pointed process on the maxilla for insertion of the retractor tentaculi muscle. In addition, the presence in the new species of an elongated anterior portion of the mesethmoid and a triangular uncinate process of the epibranchial 3 suggests a close relationshipwith Corydoras metae.(AU)
Assuntos
Animais , Especificidade da Espécie , Peixes/classificação , Bacias Hidrográficas/análise , Classificação , Biodiversidade , FilogeniaRESUMO
A new species of Corydoras is described from tributaries of the rio Arinos, rio Teles Pires and rio Preto, all in the rio Tapajós basin. The new species is a member of a group that includes 36 species with spots on the body. Within this group, the new species can be readily distinguished by having a smaller dorsal-fin spine than the first three subsequent soft dorsal-fin rays; pectoral, pelvic and anal fins hyaline; dorsal-fin interradial membrane hyaline; rounded spots on trunk restricted to dorsolateral body plates and dorsal portion of ventrolateral body plates, not reaching the base of pelvic and anal fins. The new species can be further distinguished from Corydoras xinguensis by having spots with diffuse edges, and from all other species of spotted Corydoras except C. multimaculatus, by the absence of ventral platelets. A phylogenetic analysis recovered the new species plus Corydoras metae and C. araguaiensis in a clade sharing the presence of a pointed process on the maxilla for insertion of the retractor tentaculi muscle. In addition, the presence in the new species of an elongated anterior portion of the mesethmoid and a triangular uncinate process of the epibranchial 3 suggests a close relationshipwith Corydoras metae.