RESUMO
Urophycis Gill 1864 is a genus of demersal fish composed by eight valid species with anti-tropical distributions in the western Atlantic. Only two species occur in the South Atlantic: U. brasiliensis (Kaup 1858) and U. mystacea Miranda Ribeiro 1903. These species have similar ranges from southeastern Brazil to northern Argentina, but U. brasiliensis occurs in more shallow waters than U. mystacea. Both species are important fishery resources in southern Brazil and Uruguay. Herein, we redescribe U. brasiliensis based on comparison of types and additional specimens, including the description of the Sagitta otolith, formerly place U. latus Miranda Ribeiro 1903 as a junior synonym of U. brasiliensis, and provide an updated map of distribution.
Assuntos
Gadiformes/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Argentina , Tamanho Corporal , Feminino , Gadiformes/anatomia & histologia , Gadiformes/crescimento & desenvolvimento , Masculino , Tamanho do Órgão , Terminologia como Assunto , UruguaiRESUMO
The present study evaluated the possible occurrence of cryptic species among Merluccidae from Argentina by examining sequences of cytochrome c oxidase subunit I (coI) mtDNA. This approach can discriminate Merluccius hubbsi and Merluccius australis; specimens with morphological diagnostic characters of Merluccius patagonicus formed a cohesive cluster with M. hubbsi specimens. BIN analysis confirmed the effectiveness of barcoding within a global context.
Assuntos
Código de Barras de DNA Taxonômico , Gadiformes/classificação , Animais , Argentina , Sequência de Bases , DNA Mitocondrial/genética , Gadiformes/genética , FilogeniaRESUMO
The high intraspecific variation among and the conservative external morphology of Merluccius spp. have resulted in serious identification difficulties. Four hundred and twenty fresh and preserved specimens of Merluccius were analyzed, including the type series of Merluccius australis, M. tasmanicus and M. hubbsi; specimens of M. hubbsi from Argentina, Brazil and Uruguay, and individuals of M. australis from Argentina and New Zealand were examined. The nomenclatural status of the type specimens of M. australis is discussed and the designation of a lectotype and a paralectotype is proposed. The comparative study of morphology, meristic, traditional and landmark-based morphometry, both external and internal, and through DNA-based Barcoding molecular tools demonstrates that Merluccius tasmanicus is a junior synonym of Merluccius australis. Meristic and morphometric characters of types of M. tasmanicus completely overlap those of M. australis, whereas M. hubbsi show fewer scales along the lateral line, total vertebrae, second dorsal and anal-fin rays. A trend of a longer snout and wider head in M. australis and M. tasmanicus, and larger eyes and longer pelvic fins, in M. hubbsi was observed. While discriminant characters were found in the internal elements (hyomandibula, urohyal and sagitta otolith) between M. hubbsi and M. australis, none were observed between M. australis and those reported for M. tasmanicus. DNA barcoding analyses found no evidence of the existence of other species of Merluccius besides M. hubbsi and M. australis.
Assuntos
Gadiformes/classificação , Gadiformes/genética , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Argentina , Tamanho Corporal , Feminino , Gadiformes/anatomia & histologia , Gadiformes/crescimento & desenvolvimento , Masculino , Tamanho do Órgão , Filogenia , Terminologia como AssuntoRESUMO
Genetic variation and divergence among samples of Chilean hake Merluccius gayi, from three localities off the coast of Chile and one locality off the coast of northern Peru, were assessed using sequences from the control region of mitochondrial DNA. Homogeneity tests revealed occurrence of at least three distinct genetic stocks of M. gayi within the region sampled. Factors potentially contributing to genetic divergence among M. gayi probably include hydrodynamics and behaviour.
Assuntos
DNA Mitocondrial/genética , Gadiformes/classificação , Gadiformes/genética , Variação Genética , Animais , Chile , Genética Populacional , Haplótipos , Dados de Sequência Molecular , Peru , Especificidade da EspécieRESUMO
The aims of the present study were to compare, using multivariate analyses, the degree of similarity of the endoparasite fauna of five fish species belonging to the order Gadiformes: Merluccius gayi, Merluccius australis, Macruronus magellanicus (Gadoidei) and Micromesistius australis and Nezumia pulchella (Macrouroidei), from the southern and central Chilean coast, and to evaluate whether the composition of the endoparasite fauna was determined by phylogenetic or ecological relationships. We employed our database of Merluccius australis, M. magellanicus and Micromesistius australis, which was complemented with published information for M. magellanicus, Merluccius australis, Micromesistius australis, M. gayi and N. pulchella. A higher number of endoparasite species was recorded for Merluccius australis, Micromesistius australis and M. magellanicus, namely Anisakis sp. and Hepatoxylon trichiuri, which is the most prevalent parasite among these hosts. Aporocotyle wilhelmi and Hysterothylacium sp. were detected only in M. gayi, whereas Lepidapedon sp. was found exclusively in N. pulchella. These results suggest that fish ecology rather than host phylogeny was the most important factor for the determination of similarity in parasite composition. This result could be explained by the similar trophic patterns of hosts and by the predominance of generalist larval species among these fish parasite communities.
Assuntos
Doenças dos Peixes/parasitologia , Gadiformes/parasitologia , Especificidade de Hospedeiro , Parasitos/fisiologia , Animais , Chile , Ecologia , Gadiformes/classificação , Gadiformes/crescimento & desenvolvimento , Parasitos/classificação , Parasitos/isolamento & purificação , FilogeniaRESUMO
Morphologically, both classic and landmark-based morphometry and meristic analyses of 241 specimens of Merluccius, along with the re-examination of six paratype specimens of Merluccius hubbsi, the holotype and three paratypes of Merluccius patagonicus and the syntype of Merluccius australis revealed the presence of only two species of Merluccius in Argentinean waters. Internal structures (hyomandibula, urohyal and sagitta otolith) of M. hubbsi were compared to those reported for M. patagonicus and were shown to have identical morphology. Type specimens of M. patagonicus showed a complete overlap in morphometric and meristic characters with M. hubbsi, whereas M. australis had a greater number of second dorsal and anal-fin rays, and more lateral-line scales. In addition, M. australis had a smaller eye and longer snout than M. hubbsi and M. patagonicus. The results indicate that there is no evidence for a third hake species in Argentinean waters. Merluccius patagonicus is a synonym of M. hubbsi.
Assuntos
Gadiformes/classificação , Nadadeiras de Animais/anatomia & histologia , Animais , Argentina , Oceano Atlântico , Tamanho Corporal , Osso e Ossos/anatomia & histologia , Feminino , Gadiformes/anatomia & histologia , Masculino , Especificidade da EspécieRESUMO
A new species of the macrourine genus Nezumia is described from specimens collected from the crest of Fieberling Guyot in the eastern North Pacific Ocean. The new species is distinguishable from all other Nezumia species chiefly on the basis of a high number of pelvic fin rays, a relatively high number of first dorsal fin soft rays, a steep blunt snout lacking scales ventrally, a relatively weak suborbital ridge, and a moderately long, thin barbel. Although possibly endemic to the Baja California Seamount Province, the new species appears to lack close relatives among the other Nezumia species of the eastern North Pacific Ocean. It might have arrived there either from a disjunct Tethyan distribution, thus retaining close relatives among the Atlantic Ocean species of Nezumia, or by way of stepping-stone dispersal from the Indo-west Pacific Ocean.
Assuntos
Animais , Feminino , Gadiformes/classificação , Gadiformes/anatomia & histologia , Geografia , Oceano PacíficoRESUMO
Two unusual specimens of the grenadier genus Coryphaenoides were collected by the deep-submersible vehicle Johnson Sea-Link off the Galápagos. Unlike any other member of the genus, the snout in these specimens was rounded, non-protruding, naked anteriorly and ventrally, with no tubercular scales marking the terminal and lateral angles. They are herein described as Coryphaenoides gypsochilus. Additional specimens of grenadiers were procured by the Johnson Sea-Link, including the second and third specimens of Nezumia ventralis and the first record of Caelorinchus canus from these waters. Three species and one subspecies of Galápagos grenadiers are endemic.
Assuntos
Animais , Masculino , Gadiformes/classificação , Equador , Gadiformes/anatomia & histologiaRESUMO
Two unusual specimens of the grenadier genus Coryphaenoides were collected by the deep-submersible vehicle Johnson Sea-Link off the Galápagos. Unlike any other member of the genus, the snout in these specimens was rounded, non-protruding, naked anteriorly and ventrally, with no tubercular scales marking the terminal and lateral angles. They are herein described as Coryphaenoides gypsochilus. Additional specimens of grenadiers were procured by the Johnson Sea-Link, including the second and third specimens of Nezumia ventralis and the first record of Caelorinchus canus from these waters. Three species and one subspecies of Galápagos grenadiers are endemic.
Assuntos
Gadiformes/classificação , Animais , Equador , Gadiformes/anatomia & histologia , MasculinoRESUMO
A new species of the macrourine genus Nezumia is described from specimens collected from the crest of Fieberling Guyot in the eastern North Pacific Ocean. The new species is distinguishable from all other Nezumia species chiefly on the basis of a high number of pelvic fin rays, a relatively high number of first dorsal fin soft rays, a steep blunt snout lacking scales ventrally, a relatively weak suborbital ridge, and a moderately long, thin barbel. Although possibly endemic to the Baja California Seamount Province, the new species appears to lack close relatives among the other Nezumia species of the eastern North Pacific Ocean. It might have arrived there either from a disjunct Tethyan distribution, thus retaining close relatives among the Atlantic Ocean species of Nezumia, or by way of stepping-stone dispersal from the Indo-west Pacific Ocean.