Maria Elina Bichuette

Pimelodella spelaea: A New Cave Catfish from Central Brazil, with Data on Ecology and Evolutionary Considerations (Siluriformes: Heptapteridae)

Abstract Pimelodella spelaea, new species, is described from a subterranean stream tributary to the São Bernardo River inside the São Bernardo Cave, in the São Domingos karst area, upper Tocantins River basin, central Brazil. The new species can be distinguished from its epigean (surface) congeners by derived troglomorphic features such as smaller eyes and fainter coloration, which are nevertheless less reduced than in the other known troglobitic (exclusively subterranean) species, Pimelodella kronei, from southeast Brazil. Ecological data such as habitat characteristics, population data based on mark-recapture techniques, and distributions of frequencies of standard length, weight, and condition factor, were obtained during the dry season of 2000 (May to September). A relatively high population density (about one individual per m−2) was recorded for the accessible habitat, which is probably much lower in the nonaccessible, phreatic area of distribution. The low condition factor recorded for P. spelaea, which tended to decrease along the study period, indicates a regime of severe food limitation, intensifying along the dry season. An allopatric model of differentiation is hypothesized, either because of topographic isolation or because of local extinction of epigean relatives, or both factors combined. The conservation status of the new species is also discussed.

A new species of Glaphyropoma: the first subterranean copionodontine catfish and the first occurrence of opercular odontodes in the subfamily (Siluriformes: Trichomycteridae)

A new species of the rare copionodontine genus Glaphyropoma is described from subterranean waters in the Diamantina Plateau, Bahia State, central northeastern Brazil. This is the first troglomorphic species in the subfamily Copionodontinae. It is distinguished from all other copionodontines by the presence of opercular odontodes, and further distinguished from its only congener, G. rodriguesi, by the reduction of dark integumentary pigmentation. The new species shares the single synapomorphy previously proposed for Glaphyropoma, the marked narrowing of the first hypobranchial and indirect character evidence also supports its inclusion in the genus. The presence of opercular odontodes in the new species, in combination with a reviewed hypothesis of sister group relationship between Copionodontinae and Trichogeninae, indicate that the absence of opercular odontodes in previously-known copionodontines is secondary, rather than primitive.

Surface and subterranean ichthyofauna in the Serra do Ramalho karst area, northeastern Brazil, with updated lists of Brazilian troglobitic and troglophilic fishes

After an ichthyofaunistic survey in several epigean (surface) water bodies of the Serra do Ramalho, southern Bahia, conducted in May 2007, 44 species were recorded; in addition, three non-troglomorphic (normally eyed and pigmented) and two troglomorphic species were recorded only in caves, totaling 49 species of fishes for the area, which represents a little more than one fourth of the total registered in the literature for the entire Rio Sao Francisco basin. In these caves, which have been studied since 2005, eight non-troglomorphic species were sampled and their presence in both epigean and subterranean habitats, associated to the lack of morphological differences, indicate that they may be either troglophiles (species encompassing individuals able to live and complete their life cycle either in the surface or in the subterranean environment), trogloxenes (individuals regularly found in subterranean habitats, but which must return periodically to the surface in order to complete their life cycle) or even accidental in caves. In addition, two troglomorphic species (with reduced eyes and melanic pigmentation when compared to close epigean relatives), belonging respectively to the genera Rhamdia and Trichomycterus, were recorded exclusively in caves, thus classified as troglobites. Interestingly, no epigean representative of the genus Trichomycterus was collected. The new data are integrated into updated lists of Brazilian troglobitic and troglophilic fishes, based on published data and new records recently confirmed.

Ituglanis mambai, a new subterranean catfish from a karst area of Central Brazil, rio Tocantins basin (Siluriformes: Trichomycteridae)

Ituglanis mambai, new species, is described from a cave in the Mambai karst area, State of Goias, Central Brazil. The new species distinguishes from epigean and cave congeners by the combination of the following characteristics: posterior supraoccipital fontanel absent; pectoral-fin rays usually i,7; six pleural ribs; total vertebrae 37-38 behind Weberian apparatus; shorter predorsal length (65.1-70.8% SL); shorter caudal peduncle length (8.4-11.9% SL); shorter dorsal-fin base length (7.7-11.3% SL); wider interobital width (29.2-36.5% HL); larger mouth width (43.4-64.0% HL); intermediate between epigean and other cave Ituglanis species as regards to both eyes (diameter varying from 0.5 to1.0 mm in adults, 7.8-10.1 % HL) and pigmentation, composed by irregular light brown spots along the body. The latter indicate the troglobitic status for I. mambai. In addition, this species has the maxillae with a discrete medial-posterior projection; fronto-lacrimal one half-length of the maxillae and pointed backwards; posterior process of palatine half its length, with a tenuous medial concavity; 14 dorsal and 12 ventral procurrent rays. In the natural habitat, I. mambai displayed cryptobiotic habits, trying to hide in the graveled bottom or under boulders when disturbed, apparently showing a negative response to light. It was observed a preference to slow-moving waters. Recent flood marks were observed in the stream conduit in March/April 2007 (end of the rainy season) when less individuals were observed on 300 m of the subterranean stream compared to September 2004 (end of the dry season).

Spots of high diversity of troglobites in Brazil: the challenge of measuring subterranean diversity

Subterranean ecosystems are among the most fragile and threatened worldwide. Among organisms living in the subterranean domain, source populations restricted to subterranean habitats are called troglobites, generally distinguished by sets of morphological, physiological, and ecological specializations. The singularities at both systemic (high dark and phylogenetic diversities) and species levels greatly contribute to regional and global biodiversity. However, good descriptive and interpretative knowledge about this diversity, which is important as a basis for effective conservation policies, is lacking especially for tropical areas. We describe and characterize Brazilian karst areas recognized as spots of high diversity of troglobites, highlighting particularly important cave systems. We considered not only taxonomic richness but also indicators of phylogenetic (e.g., presence of relictual taxa) and genetic diversities, the latter based on degree of specialization of individual species, i.e., accumulation of autapomorphies. For this, we used available literature and our own data, both published and unpublished. Only identifications validated by a taxonomist were considered, while all data based on parataxonomy were disregarded. We propose hypotheses based on models of origin of troglobites aiming to explain the differences between karst areas.

Taxonomic distinctness and conservation of a new high biodiversity subterranean area in Brazil

Subterranean environments, even though they do not possess a primary production (photosynthesis), may present high biodiversity, faunistic originality, endemism, phylogenetic isolations and unique ecological and/or evolution events, in addition to rare taxa. Studies investigating the biological diversity in Neotropical caves are relatively rare and recent, and most of them have been conducted in Brazil. We sampled caves from the state of Bahia, northeastern Brazil, and through sampling sufficiency tests and richness estimators, we demonstrate that the normatization for the Brazilian cave laws is not adequate for its conservation and that only α diversity index is not enough to verify faunistic patterns. We suggest that a phylogenetic diversity index be more robust and accurate for conservation purposes, particularly the Taxonomic Distinctness index. Moreover, we propose that the sandstone complex caves from Chapada Diamantina National Park need to be classified as being of high subterranean biodiversity in a global scope.

Does the Cave Environment Reduce Functional Diversity

Caves are not colonised by all taxa present in the surface species pool, due to absence of light and the tendency to food limitation when compared to surface communities. Under strong species sorting during colonisation and later by the restrictive environmental filter, traits that are not adaptive in subterranean habitats may be filtered out. We tested whether cave communities were assembled by the restrictive regime propitiated by permanent darkness or by competitive exclusion due to resource scarcity. When compared to surface communities, the restrictive subterranean regime would lead to lower functional diversity and phenotypic clustering inside the caves, and the opposite should be expected in the case of competitive exclusion. Using isopods (Oniscidea) as model taxa, we measured several niche descriptors of taxa from surface and cave habitats, used a multivariate measure of functional diversity, and compared their widths. We found phenotypic overdispersion and higher functional diversity in cave taxa when compared to surface taxa. On the one hand, the dry climate outside of caves hampered the survival of several taxa and their ecological strategies, not viable under severe desiccation risk, culminating in the clustering of functional traits. In contrast, this restriction does not occur inside of caves, where isopods find favourable conditions under lower predation pressures and more amenable environmental parameters that allow occupation and subsequent diversification. Our results showed that, at least for some taxa, caves may not be such a harsh environment as previously thought. The high functional diversity we found inside caves adds an additional reason for the conservation of these sensitive environments.

Tmesiphantes hypogeus sp. nov. (Araneae, Theraphosidae), the first troglobitic tarantula from Brazil

A new species of Tmesiphantes Simon, 1892, is described from sandstone/quartizitic caves of Chapada Diamantina, Bahia State, Brazil. This is the fifth species of the genus and the first record of a troglobitic mygalomorph in Brazil. A key is presented for all Tmesiphantes species.

Rediscovery and redescription of the unusual subterranean characiform Stygichthys typhlops, with notes on its life history

The rediscovery of the enigmatic subterranean characiform Stygichthys typhlops is reported almost a half-century after the collection of the holotype, the only specimen previously known. Thirty-four specimens were collected in two shallow hand-dug wells at the region of the type locality, c. 13 km south-west of the town of Jaíba, Minas Gerais, Brazil. These specimens provide new information on the morphology of this species, and for the first time on its life history. The conservation status of S. typhlops is discussed. The species is severely threatened by habitat loss caused by exploitation of the aquifer.

Ituglanis boticario, a new troglomorphic catfish (Teleostei: Siluriformes: Trichomycteridae) from Mambaí karst area, central Brazil

A new subterranean and troglomorphic species of Ituglanis Costa and Bockmann, 1993 is described from the carbonatic karst area of northeastern Goias state, upper Tocantins River Basin, central Brazil, representing the sixth subterranean species of the genus described from the same region. Ituglanis boticario sp. nov. is diagnosed by a combination of unusual characters for the genus: body pigmentation forming longitudinal stripes, 7-8 pairs of ribs, presence of the anterior segment of the infraorbital laterosensory canal, and usually 8 pectoral-fin rays. Due to the absence of epigean populations and the presence of some degree of morphological specialization to the subterranean environment, it can be classified as a troglobite (i.e., exclusively subterranean). The description of this species increases the importance of the northeastern Goias region as a biodiversity spot for subterranean ichthyofauna, mainly Ituglanis. The region demands urgent political efforts to ensure the preservation of its speleobiological patrimony, including the Tarimba cave system, one of the largest caves in Brazil and type-locality of I. boticario sp. nov.