Wednesday, November 10, 2021

[Ichthyology • 2021] Apteronotus albertoi • The Description of A Rare and Critically Endangered Species of Ghost Knifefish (Gymnotiformes: Apteronotidae) from the Amazon Basin, Brazil

Apteronotus albertoi
Peixoto, Dutra, Datovo, Menezes & De Santana, 2021

A new species of ghost knifefish is described from the Rio Uatumã at Cachoeira do Miriti, Amazon basin, Brazil. It is distinguished from all species of Apteronotus by the absence of a clear stripe from the chin to the dorsal portions of the head and/or dorsum, a reduced number of anal-fin rays (118–122), and by having four branchiostegal rays. More specifically, the new species resembles Apteronotus quilombola by the low number of anal-fin rays; however, the number of branchiostegal rays and several additional counts and measurements differentiate the species. Furthermore, the new species co-occurs with A. lindalvae, and it can be distinguished by the number of premaxillary teeth. The occurrence area of the new species was highly impacted after the construction of Balbina dam. Thus, considering the threats to the species and the restricted area of distribution, its conservation status was assessed as critically endangered.

Lateral view of the type series of Apteronotus albertoi:
(A) INPA 16149, holotype, male, 71.9 mm TL. Paratypes: (B) INPA 59635, female, 63.6 mm LEA. Undetermined sex specimens: INPA 59635: (C) 57.1 mm LEA;
(D) 56.0 mm LEA; (E) 54.7 mm LEA; (F) MZUSP 125829, 55.8 mm LEA.
Arrow indicates position of the dorsal organ.

Apteronotus albertoi, new species

Etymology.— The specific epithet albertoi (a patronym in genitive case) is in honor of Dr. Alberto Carvalho, who is the manager of the ‘‘Laboratorio Multiusuário de Processamento de Imagens de Microtomografia Computadorizada de Alta Resolução do Museu de Zoologia da Universidade de São Paulo,’’ in recognition of his kind support in generating lCT scan images for MZUSP researchers, especially for the project ‘‘Diversity and Evolution of the Gymnotiformes.’’

 Geographical distribution.— Apteronotus albertoi is only known from its type locality, the Uatumã River at Cachoeira do Miriti, Amazon basin, Brazil (Fig. 3).

Luiz Antônio Wanderley Peixoto, Guilherme Moreira Dutra, Aléssio Datovo, Naércio Aquino Menezes and Carlos David De Santana. 2021. The Description of A Rare and Critically Endangered Species of Ghost Knifefish from the Amazon Basin (Ostariophysi: Gymnotiformes: Apteronotidae). Ichthyology & Herpetology. 109(4); 1002-1009. DOI: 10.1643/i2020157