نتایج جستجو برای: teleostei
تعداد نتایج: 2699 فیلتر نتایج به سال:
Ninety individuals of the characid fish Astyanax fasciatus (Cuvier, 1819) were collected at Água da Madalena stream (Botucatu, São Paulo, Brazil) and analyzed for diploid chromosome number 2n and karyotype composition as well as for the chromosomal location of the 5S and 18S ribosomal DNA (rDNA). Whereas no chromosome differences were associated with sex, three different karyomorphs with diploi...
Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization i...
Natural populations subjected to strong environmental selection pressures offer a window into the genetic underpinnings of evolutionary change. Cavefish populations, Astyanax mexicanus (Teleostei: Characiphysi), exhibit repeated, independent evolution for a variety of traits including eye degeneration, pigment loss, increased size and number of taste buds and mechanosensory organs, and shifts i...
Boxfishes (Teleostei: Ostraciidae) are rigid-body, multi-propulsor swimmers that exhibit unusually small amplitude recoil movements during rectilinear locomotion. Mechanisms producing the smooth swimming trajectories of these fishes are unknown, however. Therefore, we have studied the roles the bony carapaces of these fishes play in generating this dynamic stability. Features of the carapaces o...
Schistura andrewi, a new species of loach, is described from a tributary of Kaladan River in Mizoram, northeastern India. It is distinguished from its congeners in having the following combination of characters: long axillary pelvic lobe; complete lateral line with 82-95 pores; 2 unbranched dorsal and anal fin rays; 6-7 broad, wider than interspace, black bars on the body; 2 rows of black spots...
A new species of damselfish, Altrichthys aleliasp. n. is described from specimens collected in shallow water (1-8m depth) off Busuanga Island, Palawan Province, Philippines. It differs from the other two species in the genus, A. curatus and A. azurelineatus, in various features including having golden upper body lacking dark edges of dorsal and caudal fins, higher modal number of tubed lateral ...
Determining the costs of sexual ornaments is complicated by the fact that ornaments are often integrated with other, non-sexual traits, making it difficult to dissect the effect of ornaments independent of other aspects of the phenotype. Hybridization can produce reduced phenotypic integration, allowing one to evaluate performance across a broad range of multivariate trait values. Here we asses...
Fishes currently assigned to Pethia gelius Hamilton from West Bengal are shown to belong to a closely-related group of three species: P gelius, its erstwhile synonym P canius Hamilton and a new species, P aurea. The three species are distinguished from all other species of Pethia by having the lateral line incomplete, with 3-4 pored scales; 20-26 scales in lateral series on body; ½4-5/l/2-3½ sc...
Atherinella blackburni is a silverside species whose occurrence on the Brazilian coast was not properly registered until recently. So far, records of its distribution along the Brazilian shore were limited to Itaparica Island, Bahia State, and Porto Inhaúma, Rio de Janeiro State. In a recent survey of the ichthyofauna of Itamambuca Beach, Ubatuba, São Paulo State, 100 specimens of this species ...
Lophotidae, or crestfishes, is a family of rare deep-sea teleosts characterised by an enlarged horn-like crest on the forehead. They are poorly represented in the fossil record, by only three described taxa. One specimen attributed to Lophotidae has been described from the pelagic fauna of the middle-late Eocene Zagros Basin, Iran. Originally considered as a specimen of the fossil lophotid †Pro...
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