Revisão taxonômica do gênero Achirus (Pleuronectiformes: Achiridae) e a descrição anatômica das espécies Achirus declivis e Achirus lineatus da região sudeste do Brasil

Abstract

The genus Achirus is composed by nine species present in oceans and rivers on both sides of North, Central, and South America. Due to a lack of adequate anatomical descriptions and a recent study that encompasses all species comprising the genus, the species are often difficult to be identified and studied under a phylogenetic/biogeographycal perspective. This study reviewed the taxonomy of the genus Achirus by a morphological/osteological analysis of some species (cf. Achirus lineatus and Achirus declivis), comparing them with existing data in literature. The results suggest that all species are valid, however, shows a lack of information on Achirus mucuri and Achirus zebrinus. Achirus declivis differed from Achirus lineatus by a steeper dorsal region, the premaxillary ascending process of the blind side obliquely directed with an expanded anterior process, and a well developed pectoral fin. Achirus achirus presented a geographical range significantly greater than documented in the literature. Additionally, we present an identification key comprising all species of the genus Achirus as well as a review of its geographical distribution, comparing them with biogeographical models for neotropical taxa proposed in literature.