Epigean and subterranean ichthyofauna in Cordisburgo karst area, eastern Brazil

Abstract

After an ichthyofaunistic survey conducted in May 2007 on surface (epigean) water bodies of Cordisburgo karst area, State of Minas Gerais, 13 species were recorded, mostly characiforms; in addition three non-troglomorphic (normally eyed and pigmented) and one troglomorphic catfish (siluriforms) species were recorded in two caves surveyed at different occasions, totaling 17 fish species for the area. All the nominal species herein reported for Cordisburgo area have been previously reported for the Rio das Velhas basin. None of the species observed in caves were found in epigean habitats and vice-versa. The four cave species are distributed throughout subterranean stream reaches, with individuals at different size/age classes. This, associated to the lack of conspicuous morphological differences in relation to epigean congeners, indicate that Trichomycterus brasiliensis, Gymnotus cf. carapo and Pimelodella cf. vittata are troglophiles (species encompassing individuals able to live and complete their life cycle either in the surface or in the subterranean environment) in the Morena Cave; the latter forms a large population and may be at the beginning of a differentiation process due to isolation in the subterranean habitat, as indicated by a slight reduction in eye size. Topographic isolation may be the cause for the incipient, but unmistakable troglomorphism of the Rhamdiopsis population found in the Salitre Cave, allowing for its classification as troglobite (exclusively subterranean species). The Cordisburgo area is subject to significant anthropic pressure, mainly represented by deforestation for agriculture, cattle raising and timbering. Tourism is an additional important threat for cave communities, calling for urgent protection measures.

First report of armored catfishes Callichthyinae Bonaparte, 1838 (Siluriformes: Callichthyidae) in the subterranean domain of northern and northeastern Brazil

“…Even in the extensive fieldworks focusing the ichthyofauna of Brazilian subterranean drainages, the record of Callichthyidae is quite uncommon (see Bichuette and Trajano 2003, Mattox et al 2008, Trajano et al 2009a, 2009b, Cordeiro et al 2013, Secutti and Bichuette 2013. Recently, the first troglobitic Callichthyidae was described from a cave system in Central Brazil, Aspidoras mephisto Tencatt and Bichuette, 2017, and the fact that this species is the only species of Callichthydae occurring in a cave system of about 6 km indicates that perhaps members of this family has some ecological and/ or behavioral assumptions and maybe they cannot syntopically occur or are excluded in a competition for space and/or other resources in the subterranean drainages.…”

“…Bichuette and Trajano 2003, Mattox et al 2008, Trajano et al 2009a, 2009b, Cordeiro et al 2013, Secutti and Bichuette 2013 (Fig. 4).…”

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“…Trabalhos dessa natureza no Brasil, além de serem poucos, têm sido realizados somente em duas bacias, a do rio Tocantins (Bichuette e Trajano, 2003;De Paula et al, 2012) e a do rio São Francisco (Mattox et al, 2008;Trajano et al, 2009;Secutti e Bichuette, 2013). Apesar disso, esses trabalhos têm revelado novas populações de espé-cies troglófilas, e também contribuído para descoberta de novas espécies troglóbias.…”

Ictiofauna da área cárstica de Presidente Olegário, estado de Minas Gerais, com ênfase nas espécies subterrâneas

“…A área cárstica de Presidente Olegário, é extremamente escassa de estudos no que concerne a ictiofauna, sendo o presente o primeiro que foca ambientes subterrâneos. Trabalho semelhante para a mesma bacia hidrográfica foi realizado em Cordisburgo, norte de Minas Gerais (Trajano et al, 2009), revelando quatro espécies novas de peixes (três troglófilas e uma troglóbia), demonstrando a importância de estudos com este foco.…”