Unexpectedly high diversity in a small basin: A taxonomic revision of Eurycheilichthys (Siluriformes: Loricariidae), with descriptions of seven new species

• Autor(a) principal: Reis,Roberto E.
• Data de Publicação: 2017
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Neotropical ichthyology (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000100211
• topic: Biodiversity; Catfish; Endemism; Identification key; Systematics

ABSTRACT A taxonomic revision of Eurycheilichthys is provided, and seven new species are described in addition to the two previously known species in this genus: E. pantherinus from the upper rio Uruguay, and E. limulus from the upper rio Jacuí. The genus is diagnosed based on the uniquely derived presence of seven branched pectoral-fin rays, and on the possession of reduced filamentous gill rakers in the oral surface of the hyobranchial skeleton, and presence of a distinct fleshy flap along the posterodorsal margin of the pectoral-fin spine in adult males. The seven new species are described from tributaries to the rio Taquari basin, itself a tributary to the rio Jacuí in Rio Grande do Sul State, southern Brazil. The new species are diagnosed based on color variation, abdominal plate morphology, lip size, parieto-supraoccipital shape, the number of dermal plates, the number of teeth, and body proportions. The high diversity and degree of species endemism in a limited area are discussed and compared to other fish groups. Genetic sequences (GenSeq) of mitochondrial and nuclear DNA, distribution maps, an identification key, and illustrations are presented for all species.