A new species of Eigenmannia Jordan & Evermann (Gymnotiformes: Sternopygidae) from rio Tapajós, Brazil, with discussion on its species group and the myology within Eigenmanniinae.

Luiz Antônio Wanderley Peixoto,Willian M Ohara,Claudia Patricia Tambussi

doi:10.1371/journal.pone.0220287

Luiz Antônio Wanderley Peixoto, Willian M Ohara + Show 1 more

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https://doi.org/10.1371/journal.pone.0220287

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Abstract

A new species of Eigenmannia is described from the rio Mutum, tributary of upper rio Juruena, rio Tapajós basin, Comodoro, Mato Grosso, Brazil. The new species is distinguished from all congeners by coloration pattern, position of the mouth, number of scales rows above lateral line, number of premaxillary and dentary teeth, number of precaudal vertebrae, orbital diameter, mouth width, relative depth of posterodorsal expansion on infraorbitals 1+2 and relative size of coronomeckelian bone. Comments on potentially useful characters in phylogenetic studies derived from musculature, discussion on Eigenmannia species-group and the first dichotomous key for Eigenmannia are provided.

Highlights

IntroductionSpecies allocated in Eigenmannia Jordan & Evermann are small- to medium-sized omnivores (up to 350 mm of total length), with insectivorous trends [1,2,3]
Species allocated in Eigenmannia Jordan & Evermann are small- to medium-sized omnivores, with insectivorous trends [1,2,3]
Anatomical studies in Gymnotiformes follow the trend of efforts implemented in other Teleostei groups and focused on detailed descriptions of distinct osteological complexes (e.g., [15,32,48]), neuroanatomical structures or anatomical components associated with electrogenesis and electroreception (e.g., [37,38,49,50,51])

Summary

Introduction

Species allocated in Eigenmannia Jordan & Evermann are small- to medium-sized omnivores (up to 350 mm of total length), with insectivorous trends [1,2,3]. They inhabit floodplains, terra firme streams, river channels or caves [4,5], and use a monophasic electric organ discharge to discharges ranging from 100 to 780 Hz in order to communicate and explore environment [6]. Despite several taxonomic contributions (e.g., [11,12,13,14,15,16,17]), the monophyly of Eigenmannia is currently doubtful (cf. [18,19,20,21]), and its taxonomy is grounded on group of species, a similar condition found in several Neotropical fishes that are waiting for taxonomic and phylogenetics efforts to bring light to its classification (e.g. Apistogramma Regan, Corydoras Lacepède, Hyphessobrycon Durbin, Moenkhausia Eigenmann).

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