Two new species of terrestrial isopods are described from iron ore caves in Brazil, within the Amazon biome, Circoniscus mendesi López-Orozco, Campos-Filho & Bichuette sp. nov. and C. xikrin López-Orozco, Campos-Filho & Carpio-Díaz sp. nov. (Scleropactidae). In addition, the knowledge of the distribution of Ctenorillo ferrarai Campos-Filho, Araujo & Taiti, 2014 (Armadillidae) is extended to Parauapebas, and Benthanoides tarzan Cardoso & Ferreira, 2023 to south area of the Campos Ferruginosos National Park, both in the State of Pará. Moreover, a distribution map and photographs of the species are given.

Two new troglobitic species of Xangoniscus are described from two caves of Serra do Ramalho karst area, Bambuí geomorphological group, state of Bahia. Xangoniscus lapaensis sp. nov. is described from Gruna Boca da Lapa cave, and X. loboi sp. nov. from Gruna da Pingueira II cave. Both species are blind and depigmented and show amphibious habits, as observed for all species of Xangoniscus described until now. Xangoniscus lapaensis sp. nov. occurs in travertine pools fed by water of the upper aquifer, and X. loboi sp. nov. occurs in a small stream, an upper vadose tributary. Both species occur in fragile microhabitats. Ecological and behavioral data, conservation remarks, and IUCN conservation assessments are included to provide background data for conservation efforts in this unique karst area.

Two new species of Pectenoniscus from two caves in karst areas of the Brazilian semiarid region are described. Pectenoniscus pankaru Campos-Filho, Torres & Bichuette, sp. nov. from Gruna do Govi cave, Serra do Ramalho karst area, state of Bahia, and Pectenoniscus fervens Campos-Filho, Taiti & Bichuette, sp. nov. from Toca Coroa do Frade cave, Barra Bonita karst area, state of Piauí. In addition, specimens of Cylindroniscus flaviae from Gruta da Tapagem (= Caverna do Diabo), Açungui karst area were also recorded. An updated diagnosis of Pectenoniscus and a distribution map of the species examined herein are given.

The caves of Igatu, municipality of Andaraí, belonging to the region known as Chapada Diamantina represent a new hotspot of subterranean fauna. These caves are siliciclastic, which are sedimentary rocks where silica predominates, such as sandstones and (following metamorphism) quartzites, which makes them even more relevant from the point of view of subterranean diversity. For five caves, which we named Igatu Cave System (ICS), thirty-seven obligate cave species were found, of which thirty-five were troglobitic and two were stygobitic. The troglobitic taxa for ICS belong to three phyla, nine classes, 18 orders, and 32 families, representing a high phylogenetic diversity. Some taxa were, for the first time, reported as troglobitic in Brazil and even worldwide, such as Acari and scutigeromorphans (Chilopoda). We started the studies in 2009 and continue trough long-term monitoring projects. Some threats, severe in the past, such as “garimpo’’ (illegal small-scale artisanal mining) continue nowadays in an incipient way; however, the urban expansion due to the touristic appeal is also considered a threat. Our data ranked ICS as the Brazilian hotspot with the highest number of troglobitic/stygobitic species.

A new genus and two new species of Chelodesmidae are described from two caves of the João Rodrigues river system in Bahia state, northeastern Brazil: Strongylosomides troglobius sp. nov. and Rotundotergum elevatum gen. nov., sp. nov. The former species differs from congeners primarily by the gonopods showing the prefemoral process strongly fused caudally along its basal half to the acropodite and, in showing such troglomorphic traits as a nearly unpigmented and fragile body with thin tegument, it seems the first troglobiont to be documented in the genus. Moreover, this new species seems to be so remarkably similar to Leptodesmus stercoriarius Schubart, 1956, from Minas Gerais state, that the following new combination is warranted: Strongylosomides stercoriarius (Schubart, 1956), comb. nov. ex Leptodesmus de Saussure, 1859. The new genus, Rotundotergum gen. nov., seems to be especially similar to Eucampesmella Schubart, 1955, but differs clearly by the absence of a secondary process on the gonopodal prefemoral process, coupled with the latter being unusually long and strongly separated from the acropodite. The type species R. elevatum sp. nov., being partly clearly pigmented, seems to be only troglophilic. The region generally supports a typical dry tropical climate, whereas the caves represent sites with high humidity, this being essential for the survival of these and other species. However, these habitats remain unprotected by Brazilian law, while the João Rodrigues River system is threatened by irrigation projects, potential limestone exploitation, asphalt and road widening or construction that pass across the system and can collapse the rock, and pollution of the subterranean drainage. We hope that the new species described here could help us protect their type localities and the João Rodrigues River system as a whole.