Deep phylogenetic divergence and lack of taxonomic concordance in species of astronotus (cichlidae).

Olavo Pinhatti Colatreli,Natasha Verdasca Meliciano,Izeni Pires Farias,Daniel Toffoli,Tomas Hrbek

doi:10.1155/2012/915265

Abstract

The neotropical cichlid genus Astronotus currently comprises two valid species: A. ocellatus Agassiz, 1831 and A. crassipinnis Heckel, 1840. The diagnosis is based on color pattern and meristics counts. However, body color pattern is highly variable between regions and the meristic counts show a considerable overlap between populations differing in color patterning. They do not represent true synapomorphies that diagnose species. Purportedly the only truly diagnostic character is the presence or absence of one or more ocelli at the base of the dorsal fin, diagnosing A. ocellatus and A. crassipinnis, respectively. Using the 5′ portion of the mitochondrial COI gene and EPIC nuclear markers, the validity of the dorsal ocelli as diagnostic character was tested in individuals sampled from ten localities in the Amazon basin. Analyses rejected the hypothesis that dorsal ocelli are diagnostic at the species level. However, they revealed the existence of five hypothetical, largely allopatrically distributed morphologically cryptic species. The phylogeographic structure is not necessarily surprising, since species of the genus Astronotus have sedentary and territorial habits with low dispersal potential. The distribution of these hypothetical species is coincident with patterns observed in other Amazonian aquatic fauna, suggesting the role of common historical processes in generating current biodiversity patterns.

Highlights

The neotropical cichlid genus Astronotus currently comprises two valid species: A. ocellatus Agassiz, 1831 and A. crassipinnis Heckel, 1840 [1]
There are reported differences in color hue and patterning where A. crassipinnis is darker than A. ocellatus, the first light vertical bar is above the anal fin base in A. ocellatus versus more anteriorly in A. crassipinnis, and A. crassipinnis has two more or less well-separated dark vertical bars in the position of the first light bar in
While the presence of ocelli on the dorsal fin is considered a diagnostic character of A. ocellatus, Kullander ([1]; see http://www2.nrm.se/ve/pisces/acara/astronot.shtml), only individuals from Peru were analyzed by Kullander [1] in his reanalysis of the genus

Summary

Introduction

The neotropical cichlid genus Astronotus currently comprises two valid species: A. ocellatus Agassiz, 1831 and A. crassipinnis Heckel, 1840 [1]. Kullander [1] reports a number of diagnostic characters, with the exception of the presence of ocelli at the base of the dorsal fin in A. ocellatus and their absence in A. crassipinnis, all other characters show considerable overlap in their statistical distributions. While the presence of ocelli on the dorsal fin is considered a diagnostic character of A. ocellatus, Kullander ([1]; see http://www2.nrm.se/ve/pisces/acara/astronot.shtml), only individuals from Peru were analyzed by Kullander [1] in his reanalysis of the genus. The geographic distribution of A. ocellatus spans the whole Amazon basin and the Oyapock and Approuague drainages. It does not include the Bolivian basin which is a subbasin of the Amazon basin

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