Redescription of Astyanax multidens Eigenmann, 1908 (Characiformes: Characidae), a small characid of the Brazilian Amazon

Astyanax multidens is redescribed based on syntypes and additional specimens from the rio Amazonas at Silves, Amazonas State and Obidos, Para State, and the rios Trombetas, Tapajos, Xingu, and Araguaia. Astyanax multidens is distinguished from congeners by the unique combination of five to seven max...

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Bibliographic Details
Published in:Neotropical ichthyology 2013-01, Vol.11 (1), p.45-54
Main Authors: Marinho, MMF, Birindelli, JLO
Format: Article
Language:English
Subjects:
Astyanax multidens
Freshwater
Jupiaba paranatinga
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Summary:Astyanax multidens is redescribed based on syntypes and additional specimens from the rio Amazonas at Silves, Amazonas State and Obidos, Para State, and the rios Trombetas, Tapajos, Xingu, and Araguaia. Astyanax multidens is distinguished from congeners by the unique combination of five to seven maxillary teeth, 31 to 34 pored lateral-line scales, 20 to 23 branched anal-fin rays, and a dark triangular blotch restricted to the middle caudal-fin rays. Astyanax multidens was collected syntopically with Jupiaba paranatinga in the rio Tapajos basin and with Jupiaba cf. essequibensis in the rio Xingu basin, which have paired anteriorly oriented pelvic-fin spines, a antipredatory mechanism. Based on the external morphological similarity between Astyanax multidens and the two species of Jupiaba, their sympatric occurrence, and their distinct phylogenetic position, we interpret this a case of Batesian mimicry.Original Abstract: Astyanax multidens e redescrita com base no exame dos sintipos e especimes adicionais do rio Amazonas em Silves, AM e Obidos, PA e rios Trombetas, Tapajos, Xingu e Araguaia. Astyanax multidens distingue-se dos congeneres pela exclusiva combinacao de cinco a sete dentes no maxilar, 31 a 34 escamas perfuradas na linha lateral, 20 a 23 raios ramificados na nadadeira anal, e uma macula triangular escura restrita aos raios medianos da nadadeira caudal. Astyanax multidens foi coletada sintopicamente com Jupiaba paranatinga na bacia do rio Tapajos, e com Jupiaba cf. essequibensis na bacia do rio Xingu, que possuem espinho pelvico voltado para frente, um mecanismo antipredatorio. Baseado na similaridade morfologica externa entre Astyanax multidens e estas duas especies de Jupiaba, sua ocorrencia simpatrica, e sua distante posicao filogenetica, nos interpretamos como um caso de mimetismo Batesiano.
ISSN:1679-6225
1982-0224
DOI:10.1590/S1679-62252013000100005