First amphibious Crinocheta (Isopoda, Oniscidea) from the Neotropics with a troglobitic status: a relictual distribution.

The first freshwater amphibian representative of Crinocheta (Oniscidea) from the Neotropics is described from caves within the Brazilian Cerrado biome, state of Mato Grosso do Sul. Kadiweuoniscusrebellisgen. et sp. nov. is placed in the family Philosciidae. The present work represents a significant contribution to future studies seeking to understand the ecological and evolutionary processes of Crinocheta within the Neotropical region. Moreover, it highlights the importance of biodiversity surveys in subterranean environments toward effective conservation efforts of these unique habitats and their surroundings.

Invertebrates diversity in mountain neotropical quartzite caves: which factors can influence the composition, richness, and distribution of the cave communities?

Twenty caves located in a high altitudinal quartzite area in Brazil were examined for invertebrate richness and composition and in terms of environmental factors that determine community structure. We evaluate how distance, altitude, cave extension, environmental stability, number and size of cave entrances and stream presence can act on species composition and richness. The caves presented a high richness of troglophilic (463 spp.) and troglobitic species (6 spp.) in relation to other siliciclastic caves around the world. The average richness was 39.55 species per cave (sd = 21.87), the quantitative similarity among caves was 41% and turnover was βrepl. = 0.769. Araneae (20% of the sampled species), Diptera (18%) and Coleoptera (14%) were the dominant orders regarding species richness. Only twenty percent of the caves were placed out of the confidence interval of the average taxonomic distinctness (∆+); however, the ∆+ decreased with the increase of environmental stability. Cave extension and stream presence were the main factors determining the variation of species composition among caves. Cave extension also influenced species richness variations. Furthermore, the total richness and richness of troglobitic species increased with cave extension. The threats to these habitats further revealed that the fauna is at risk due to tourism, trampling and natural soil erosion that can promote microhabitat alterations. Therefore, quartzite caves also require special attention regarding conservation actions in order to keep their natural biological dynamics.

Population density and habitat of an endangered cave fish Eigenmannia vicentespelaea Triques, 1996 (Ostariophysi: Gymnotiformes) from a karst area in central Brazil

The troglobitic electric fish Eigenmannia vicentespelaea, endemic to a single cave-system and included in the Brazilian Red List of Threatened Fauna, was studied in relation to population densities and habitat. For comparison, we used the epigean species, E. trilineata. We verify if the population densities recorded for E. vicentespelaea follow the pattern observed for other subterranean fishes; if there are seasonal fluctuations in these densities and which environmental variables explain the densities variation. We estimated abundances and population densities during three consecutive dry seasons concomitant with habitat description and physicochemical variables measurements. For E. vicentespelaea: in six stream reaches in the São Vicente II cave. For E. trilineata: from counts of active fish in rio da Lapa. The mean population density recorded for E. vicentespelaea is considered low (0.17 ind.m-2), similar to those of E. trilineata (0.13 ind.m-2), without significant differences between the years, but with marked fluctuations during dry seasons within each year, suggesting seasonality. Estimated population size of E. vicentespelaea is considered low (270 individuals in average). Depth, water current and substrate, allied to plant debris explain better the variation of densities. Urgent actions for E. vicentespelaea conservation include protection of headsprings in Terra Ronca State Park.

O peixe troglóbio Eigenmannia vicentespelaea, endêmico de um único sistema de cavernas e incluído na Lista Brasileira de Fauna Ameaçada foi estudado em relação às densidades populacionais e hábitat. Para comparação utilizamos a espécie epígea E. trilineata. Verificamos se as densidades populacionais registradas para E. vicentespelaea seguem o padrão observado para outros peixes subterrâneos; se há flutuações sazonais nestas densidades e quais variáveis ambientais explicam as variações nas densidades. Estimamos as abundâncias e densidades populacionais ao longo de três estações secas consecutivas, concomitantes à descrição do habitat e das variáveis físico-químicas. Para E. vicentespelaea: em seis trechos de rio ao longo da caverna São Vicente II. Para E. trilineata: na contagem de peixes ativos no rio da Lapa. A densidade populcional média registrada para E. vicentespelaea é baixa (0,17 ind.m-2), similar à observada para E. trilineata (0,13 ind.m-2), sem diferenças significativas entre os anos, mas com flutuações marcantes ao longo das estações secas dentro de cada ano, sugerindo sazonalidade. O tamanho populacional estimado para E. vicentespelaea é considerado pequeno (270 indivíduos em média). Profundidade, correnteza, substrato, aliadas à concentração de detrito vegetal explicam melhor a variação nas densidades. Ações urgentes para conservação de E. vicentespelaea incluem a proteção das nascentes do Parque Estadual de Terra Ronca.

A new genus and species for the first recorded cave-dwelling Cavernicola (Platyhelminthes) from South America.

Species diversity of Brazilian cave fauna has been seriously underestimated. A karst area located in Felipe Guerra, northeastern Brazil, which is a hotspot of subterranean diversity in Brazil, has revealed more than 20 troglobitic species, most of them still undescribed. Based on recent samplings in this karst area, we document the occurrence of the suborder Cavernicola (Platyhelminthes) in South American hypogean environments for the first time and describe a new genus and species for this suborder. Hausera Leal-Zanchet & Souza, gen. n. has features concordant with those defined for the family Dimarcusidae. The new genus is characterized by two unique features, viz. an intestine extending dorsally to the brain and ovovitelline ducts located dorsally to the nerve cords, which is complemented by a combination of other characters. The type-specimens of Hauserahauseri Leal-Zanchet & Souza, sp. n. are typical stygobionts, unpigmented and eyeless, and they may constitute an oceanic relict as is the case of other stygobiotic invertebrates found in this karst area in northeastern Brazil.