Deconstructing an octongeneric misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin

• Published in: Journal of fish biology 2019-04
• Main Authors: Tencatt, L F C, Lima, F C T, Britto, M R
• Format: Article
• Language: English
• ISSN: 1095-8649

After 80 years of misidentifications, the analysis of the holotype of Corydoras arcuatus plus several non-type specimens attributed to this species allowed its recognition and also revealed a new species, both sharing the following diagnostic features: a long, arched, continuous black stripe that runs parallel to the dorsal profile of the body and extends at least from the anterior margin of the first dorsolateral body plate to the posterior portion of caudal peduncle; absence of transverse black bars on caudal fin; infraorbital 2 in contact with sphenotic and compound pterotic. In addition to these features, C. arcuatus can be distinguished from congeners by having the posterior margin of both dorsal and pectoral spines with laminar serrations directed towards their origins. Also, it an be distinguished from the new species by presenting the following combination of features: ventral surface of trunk entirely or partially covered by relatively large and coalescent platelets; absence of spots or blotches on dorsal fin; posterior margin of both dorsal and pectoral spines with serrations directed towards their tips. Finally, an identification key to all arc-striped species of Corydoras is provided. This article is protected by copyright. All rights reserved.