A new species of sexually dimorphic and rheophilic ghost knifefish (Apteronotidae: Gymnotiformes) from the Amazon basin

Author(s)

Peixoto, Luiz Antonio Wanderley ^[1] ; Datovo, Alessio ^[1] ; Menezes, Naercio Aquino ^[1] ; de Santana, Carlos David ^[2]

Affiliation

^[1] Univ Sao Paulo, Museu Zool, BR-04263000 Sao Paulo, SP - Brazil

^[2] Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Div Fishes, MRC-159, Washington, DC - USA

• Document type: Journal article
• Source: Journal of Fish Biology; v. 98, n. 3 JAN 2021.
• Web of Science Citations: 0

Abstract

A new species of ghost knifefish, Apteronotus, is described from high-energy environments in the Rios Mapuera and Trombetas (at Cachoeira Porteira waterfalls), Brazil. X-ray microcomputed tomography (mu CT scan) was used to access the internal anatomy of the type series. The new species is distinguished from all congeners by the anteriormost position of the anus, with its posterior margin extending less than one eye diameter beyond the vertical through the caudal limit of the posterior nostril, the low number of anal-fin rays (117-125) and the reduced number of branchiostegal rays (three). A series of modifications associated with secondary sexual dimorphism on the preorbital region of mature males are depicted and discussed. In addition, comments on homologies of the branchiostegal rays in Apteronotidae are provided. (AU)

• FAPESP's process: 16/19075-9 - Diversity and evolution of Gymnotiformes (Teleostei, Ostariophysi)
• Grantee: Naercio Aquino Menezes
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/05084-1 - Evolution of the skeletal musculature of the Gymnotiformes (Teleostei: Ostariophysi)
• Grantee: Luiz Antonio Wanderley Peixoto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral