Caracterização taxonômica e variação morfológica de Squaliforma gr. emarginata (Valenciennes, 1840) (Siluriformes: Loricariidae) da Amazônia brasileira

Abstract

The species of the genus Squaliforma from the Brazilian Amazon were revised and genus comprises species that were grouped into the Hypostomus emarginatus group. The taxonomic revision was made through the analysis of digital images of the species-type, original descriptions and material deposited in ichthyological collections. The recognition of valid species was based on the original descriptions and by means of morphological and meristic data of specimens analyzed, as well as through analysis of external anatomy. We examined 547 specimens of Squaliforma from the Brazilian Amazon basin deposited in the collections of the INPA, MPEG and MZUSP. In the present work, five valid were recognized as valid and distinguished from each other: Squaliforma annae occurring on the Tocantins-Araguaia River, S. emarginata in Amazonas-Solimões River and tributaries, S. horrida occurring exclusively in the Guaporé River, S. phrixosoma in Ucayali River and Upper Jurua River, and S. squalina occurring in the Branco River. A diagnosis, description (or redescription), coloring in alcohol, ecological notes, comments and map of geographical distribution is given for all the species. Three other species were synonymized with Squaliforma emarginata: S. biseriata, S. scopularia and S. virescens. In this paper five new species are proposed: Squaliforma sp. n. "Aripuanã", Squaliforma sp. n. "Roraima", Squaliforma sp. n. "Tapajos," Squaliforma sp. n. "Tocantins" and Squaliforma sp. n. "Xingu". An identification key of the nine valid Squaliforma valid species of the Amazon basin is provided.