Epigean and subterranean ichthyofauna from the São Domingos karst area, Upper Tocantins River basin, Central Brazil

Abstract

In a survey of epigean and cave streams in the São Domingos karst area, 38 species were present in the stream reaches, including 10 characiforms, 19 siluriforms, seven gymnotiforms and two perciforms. One species of Astyanax and the new armoured catfish species Parotocinclus were the most common epigean fishes in São Domingos. The most conspicuous non‐troglomorphic cave fishes were Hoplerythrinus unitaeniatus, Astyanax sp., Brycon sp. and two species of Imparfinis, with I. hollandi being the most common fish in most caves. São Domingos karst area has the most diverse and abundant Brazilian cavefish fauna, not only in terms of troglobitic species but also in general fish richness, with 22 non‐troglomorphic species recorded in caves in addition to five troglobitic ones. Most fishes examined for stomach contents had at least partially full stomachs. The studied fishes were carnivorous, feeding primarily on aquatic insects. Fishes with developed gonads recorded in caves were I. hollandi, Rhamdia quelen, Pseudocetopsis plumbeus, Hoplerythrinus unitaeniatus and Cichlasoma araguaiensis, indicating a potential for reproduction in the subterranean habitat.

Morphology and distribution of the cave knifefish Eigenmannia vicentespelaea Triques, 1996 (Gymnotiformes: Sternopygidae) from Central Brazil, with an expanded diagnosis and comments on subterranean evolution

“…and E. vicentespelaea lacks phylogenetic support. On the other hand, these are the only members of the Clade F of Eigenmanninae (sensu Albert & Campos da Paz, 1998) found in the study area (Bichuette & Trajano, 2003). Thus, the most parsimonious geographic hypothesis (to be tested in a phylogenetic framework), which would involve no local extinctions of other species closer to any of the two above mentioned, is that of a sister-group relationship between them.…”

“…captured in subterranean stream reaches may be related to a lower pressure of predation in this environment (corroborated by the record of potential predators in the epigean Rio da Lapa -Brycon sp. -see Bichuette & Trajano, 2003). This may be associated to a low interspecific competition in caves because it seems that food represented by prey living on the large amount of vegetal debris carried during floods into the studied caves is not limiting for these fishes in hypogean habitats (Bichuette, 2003).…”

“…and four gymnotiforms, Sternopygus sp., Sternarchorhynchus mesensis, Archolaemus blax, and Porotergus sp.). The epigean Eigenmannia species coexists, in the Rio da Lapa, with characiforms (Brycon undescribed species, Characidium sp., and Creagrutus britski) and siluriforms (Pseudocetopsis plumbeus, Aspidoras poecilus, Parotocinclus undescribed species, Hypostomus sp., Ancistrus sp., Phenachorhamdia tenebrosa, and Imparfinis hollandi) (Bichuette & Trajano, 2003).…”

“…(Bichuette, 2003;Bichuette & Trajano, 2003), specimens of the cave E. vicentespelaea and an epigean species were collected, allowing a comparative study of their external morphology. The identification of the epigean species equivocal became because some character states (overlapping of OD:HL and SNL:HL proportions -R. Campos-daPaz, pers.…”

Natural history and population data of fishes in caves of the Serra do Ramalho karst area, Middle São Francisco basin, northeastern Brazil

“…This, allied to the apparent isolation of the subterranean drainage, indicates that these erythrinids may be troglophilic in the Gruna do Enfurnado. Erythrinids hypothesized as troglophilic have also been recorded in caves located in some other areas, such as the São Domingos karst area, state of Goiás, and Altamira-Itaituba sandstone karst area, state of Pará (Bichuette & Trajano 2003). In spite of the rather unstable environment, subject to flash floods almost yearly, the ichthyofauna from Gruna do Enfurnado, basically composed by two species, a troglobitic and troglophilic one, is quite stable since the number of fish observed in consecutive years was fairly constant.…”