Gross morphology of the brain and some sense organs of subterranean pencil catfishes of the genus Ituglanis Costa and Bockmann, 1993 (Siluriformes, Trichomycteridae), with a discussion on sensory compensation versus preadaptation in subterranean fishes.

Subterranean organisms provide excellent opportunities to investigate morphological evolution, especially of sensory organs and structures and their processing areas in the central nervous system. We describe the gross morphology of the brain and some cephalic sensory organs (olfactory organ, eye, semicircular canals of the inner ear) and the swim bladder (a non-sensory accessory structure) of subterranean species of pencil catfishes of the genus Ituglanis Costa and Bockmann, 1993 (Siluriformes, Trichomycteridae) and compare them with an epigean species of the genus, Ituglanis goya Datovo, Aquino and Langeani, 2016. We compared qualitatively the size of the different brain regions and sense organs of the subterranean species with those of the epigean one, searching for modifications possibly associated with living in the subterranean environment. Our findings suggest that species of Ituglanis exhibit sensory characteristics that are preadaptive for the subterranean life, as only slight modifications were observed in the brains and sense organs of the subterranean species of the genus when compared with the epigean one. Because most subterranean fish species belong to lineages putatively preadapted for subterranean life, our results, discussed in the context of available information on the brain and sense organs of other subterranean species, help identify general trends for the evolution of the brain and sensory organs of subterranean fishes in general.

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.

Groundwater is a hidden global keystone ecosystem.

Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes. To foster timely global conservation of groundwater, we propose elevating the concept of keystone species into the realm of ecosystems, claiming groundwater as a keystone ecosystem that influences the integrity of many dependent ecosystems. Our global analysis shows that over half of land surface areas (52.6%) has a medium-to-high interaction with groundwater, reaching up to 74.9% when deserts and high mountains are excluded. We postulate that the intrinsic transboundary features of groundwater are critical for shifting perspectives towards more holistic approaches in aquatic ecology and beyond. Furthermore, we propose eight key themes to develop a science-policy integrated groundwater conservation agenda. Given ecosystems above and below the ground intersect at many levels, considering groundwater as an essential component of planetary health is pivotal to reduce biodiversity loss and buffer against climate change.

Three new species of Loxosceles Heinecken & Lowe, 1832 (Araneae, Sicariidae) from Brazilian caves

Three new species of recluse spiders are described from Brazilian caves with both males and females. Loxosceles boqueirao Bertani & Gallão sp. nov. is found in the State of Bahia, in the Serra do Ramalho karst area, it belongs to the rufescens species group, and is closely related to L. cardosoi Bertani, von Schimonsky & Gallão, 2018 and L. carinhanha Bertani, von Schimonsky & Gallão, 2018 from the same karst area. Thus, there are now three species in the Serra do Ramalho karst area closely related, but noticeably distinct morphologically from other species of Loxosceles. Loxosceles planetaria Bertani & Gallão sp. nov. and L. bodoquena Bertani & Gallão sp. nov. are found in the State of Mato Grosso do Sul, in the Serra da Bodoquena karst area. They belong to the gaucho species group and are closely related to L. gaucho Gertsch, 1967. These are the first species of Loxosceles described from this karst area in the State of Mato Grosso do Sul. Loxosceles boqueirao sp. nov. and L. bodoquena sp. nov. bear some troglomorphisms and are, herein, proposed as troglobitic species, whereas L. planetaria sp. nov. is proposed as a troglophilic species. Brazil has now 22 described species of Loxosceles.

A New Species of Spelaeometra Polhemus & Ferreira, 2018 (Hemiptera: Heteroptera: Hydrometridae) from a Hotspot of Troglobites in Brazil, Serra do Ramalho Karst Area.

Spelaeometra Polhemus & Ferreira, 2018 (Hemiptera: Heteroptera: Hydrometridae) is a monotypic and troglobitic genus, recently described based on material collected in the state of Minas Gerais, Brazil. From specimens collected in the Gruna do Enfurnado Cave in the Serra do Ramalho karst area, municipality of Coribe, state of Bahia, Brazil, we describe Spelaeometra hypogea Cordeiro & Moreira, sp. nov. and compare it with Spelaeometra gruta Polhemus & Ferreira, 2018. The new species is diagnosed by the general body color being pale-yellow to light-brown; antennal segments I and II being subequal in length; the reduced gular lobe, not covering any labial segment; the male proctiger without apical projections; and the male paramere with convex dorsal margin after the curvature, with a narrow hook-like apex.

Everything is similar, everything is different! Trichorhina (Oniscidea, Platyarthridae) from Brazilian caves, with descriptions of 11 new species / Tudo é parecido, tudo é diferente! Trichorhina (Oniscidea, Platyarthridae) de cavernas brasileiras, com descrições de 11 novas espécies

Abstract The present work describes 11 new species of the genus Trichorhina from Brazilian caves in the states of Bahia, Mato Grosso do Sul, Minas Gerais, Pará, and São Paulo. Moreover, the distribution of T. tomentosa has been expanded to include the states of Mato Grosso and Minas Gerais. Additionally, a distribution map and a key for all Brazilian species of Trichorhina, including epigean ones, are provided.

Resumo O presente trabalho descreve 11 novas espécies do gênero Trichorhina de cavernas brasileiras nos estados da Bahia, Mato Grosso do Sul, Minas Gerais, Pará e São Paulo. Além disso, a distribuição de T. tomentosa foi ampliada para incluir os estados de Mato Grosso e Minas Gerais. Adicionalmente, são fornecidos um mapa de distribuição e uma chave para todas as espécies brasileiras de Trichorhina, incluindo as epígeas.

Coarazuphium bambui (Carabidae: Zuphiini), a new cave-dwelling beetle from the threatened region of Serra do Ramalho, Brazil.

To date, 20 species of obligate cave-dwelling beetles are known from Brazil, and 12 belong to the Coarazuphium genus. In this paper, we describe Coarazuphium bambui sp. n., from two specimens, one male and one female, collected in the Gruna Boca da Lapa cave located in the municipality of Feira da Mata (Bahia state, Brazil). The most striking difference between C. bambui and other species of the genus is the presence of three pairs of fixed setae posteriorly on the head, combined with the slightly elytral sinuosity. We also provide an updated key for species identification of the Coarazuphium genus. Finally, we highlight the importance of the Serra do Ramalho karst area for the conservation of troglobite diversity in the Brazilian context.

Expanding the knowledge on the diversity of the cavernicolous Styloniscidae Vandel, 1952 (Oniscidea, Synocheta) from Brazil, with descriptions of two new species from the semiarid karst regions.

Two new species of Pectenoniscus from two caves in karst areas of the Brazilian semiarid region are described. Pectenoniscuspankaru Campos-Filho, Torres & Bichuette, sp. nov. from Gruna do Govi cave, Serra do Ramalho karst area, state of Bahia, and Pectenoniscusfervens Campos-Filho, Taiti & Bichuette, sp. nov. from Toca Coroa do Frade cave, Barra Bonita karst area, state of Piauí. In addition, specimens of Cylindroniscusflaviae 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.

A new genus and two new species of the millipede family Chelodesmidae from Bahia state, northeastern Brazil, including a likely troglobiont (Diplopoda, Polydesmida)

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.

Under the surface: what we know about the threats to subterranean fishes in Brazil

The present work brings information on threats to the subterranean fishes in Brazil. Currently, at least 36 species are known, 22 of which are already formally described. Endemism is the rule for most of them. Regarding their conservation, these fishes are in general considered threatened: and most of the already formally described species are included in national lists of threatened fauna, and only four of them are included in the global list of the IUCN. Regarding habitats, Brazilian subterranean fishes occur in alluvial sediments (part of the hyporheic zone), shallow base-level streams, flooded caves, lakes in the water table, upper vadose tributaries, and epikarst aquifers. We detected 11 main threats, mainly related to agriculture, pasture, and hydroelectric plans, but unmanaged tourism and pollution are also significant threats. Two threats affect a high number of species (physical change of the habitat and food restriction). The river basins with the higher number of identified threats are the upper Tocantins (eight) followed by the upper Paraguaçu (six). Effective proposals to protect this neglected component of the Brazilian biodiversity are still scarce, such as monitoring projects and their function in the subterranean communities, besides education projects aiming to develop public awareness.(AU)

O presente trabalho traz informações sobre as ameaças aos peixes subterrâneos no Brasil. Atualmente, são conhecidas pelo menos 36 espécies, 22 das quais já foram formalmente descritas. O endemismo é a regra para a maioria destas espécies. Em relação à conservação, esses peixes são em geral considerados ameaçados: a maioria das espécies já descritas está incluída em listas regionais de fauna ameaçada e apenas quatro delas estão incluídas na lista global da IUCN. Em relação aos habitats, os peixes subterrâneos brasileiros ocorrem em sedimentos aluviais (parte da zona hiporreica), riachos de nível de base, cavernas inundadas, lagos no lençol freático, tributários vadosos superiores e aquíferos no epicarste. Detectamos onze ameaças principais, a maioria relacionada à agricultura, pecuária e projetos hidrelétricos, entretanto, turismo sem planos de manejo e poluição também representam ameaças significativas. Duas ameaças afetam um grande número de espécies: a mudança física do habitat e a restrição de alimento. As bacias hidrográficas com o maior número de ameaças identificadas são a do alto Tocantins (oito) seguida pela do alto Paraguaçu (seis). Propostas eficazes para proteger esse componente negligenciado da biodiversidade brasileira são ainda escassos, como os projetos de monitoramento e sua função nas comunidades subterrâneas, além de projetos relacionados à educação, visando a sensibilização do público.(AU)

Spooky Interaction at a Distance in Cave and Surface Dwelling Electric Fishes.

Glass knifefish (Eigenmannia) are a group of weakly electric fishes found throughout the Amazon basin. Their electric organ discharges (EODs) are energetically costly adaptations used in social communication and for localizing conspecifics and other objects including prey at night and in turbid water. Interestingly, a troglobitic population of blind cavefish Eigenmannia vicentespelea survives in complete darkness in a cave system in central Brazil. We examined the effects of troglobitic conditions, which includes a complete loss of visual cues and potentially reduced food sources, by comparing the behavior and movement of freely behaving cavefish to a nearby epigean (surface) population (Eigenmannia trilineata). We found that the strengths of electric discharges in cavefish were greater than in surface fish, which may result from increased reliance on electrosensory perception, larger size, and sufficient food resources. Surface fish were recorded while feeding at night and did not show evidence of territoriality, whereas cavefish appeared to maintain territories. Surprisingly, we routinely found both surface and cavefish with sustained differences in EOD frequencies that were below 10 Hz despite being within close proximity of about 50 cm. A half century of analysis of electrosocial interactions in laboratory tanks suggest that these small differences in EOD frequencies should have triggered the "jamming avoidance response," a behavior in which fish change their EOD frequencies to increase the difference between individuals. Pairs of fish also showed significant interactions between EOD frequencies and relative movements at large distances, over 1.5 m, and at high differences in frequencies, often >50 Hz. These interactions are likely "envelope" responses in which fish alter their EOD frequency in relation to higher order features, specifically changes in the depth of modulation, of electrosocial signals.

Nutrient availability in tropical caves influences the dynamics of microbial biomass.

Few studies have evaluated the trophic level in tropical caves, and none related the microbial biomass dynamics in the immobilization of carbon and nitrogen. Here, four tropical caves of Terra Ronca State Park, Brazil, were studied: Angélica, São Bernardo, Terra Ronca I, and Terra Ronca II caves. Physical, chemical, and microbiological parameters (microbial biomass and respiration) were estimated in the dry and wet seasons. São Bernardo, Terra Ronca I, and Terra Ronca II caves presented higher nitrogen and microbial biomass nitrogen (MBN) values in the wet season than in the dry season. On the other hand, the Angélica cave showed larger amounts of nitrogen and lower MBN values in the dry season. These results indicate that caves can be adjusted in two ecological theories known as "stoichiometric decomposition" and "microbial nitrogen mining"-to the effects of nutrient availability on organic matter decomposition. The caves studied showed different environmental dynamics in relation to organic matter decomposition, which allows them to be considered unique and possess specific characteristics. Microbial biomass dynamics can be an important parameter to evaluate the availability of nutrients and ecological dynamics of the trophic network in subterranean environments.

A new centipede Schendylops Cook from eastern Brazil: the first troglobitic geophilomorph for South America (Geophilomorpha, Schendylidae).

Schendylops janelao sp. n. is described from a limestone cave located in eastern Brazil. There are several reports of geophilomorphs in Brazilian caves, however, the new species represents the first troglobite species for South America and the first for Gruta do Janelão Cave, northern Minas Gerais State. Schendylops janelao sp. n. is described based on a male specimen and differs from its congeners by a combination of 10 characters. We discuss the character-states related to subterranean life and the conservation status of the species.

Two new species and new records of terrestrial isopods (Crustacea, Isopoda, Oniscidea) from Brazilian caves.

To date, approximately 190 species of terrestrial isopods are known from Brazil and only 14 are considered troglobiotic. After the examination of a large collection from caves in Bambuí and Una geomorphological areas, along the states of Bahia, Minas Gerais and Goiás, two new troglobiotic species were recognized. Pectenoniscus liliae Campos-Filho, Bichuette Taiti sp. n. (Styloniscidae) is described from Serra do Ramalho karst area, and Benthana xiquinhoi Campos-Filho, Bichuette Taiti sp. n. (Philosciidae) from sandstone caves of Chapada Diamantina region. The latter constitutes the second troglomorphic species of the genus. Xangoniscus aganju (Styloniscidae) is also recorded from two caves in the Serra do Ramalho karst area. The systematic position of Iuiuniscus iuiuensis is briefly discussed and Venezillo congener (Armadillidae) is redescribed from São Domingos karst area.

Cylindroniscus platoi (Isopoda: Oniscidea: Styloniscidae), a new cave-dwelling species from Lagoa Santa Karst, Southeastern Brazil.

The new species Cylindroniscus platoi n. sp. is herein described. As far as known, the species occurs only in three caves developed in a continuous limestone outcrop at Pedro Leopoldo municipality, Minas Gerais State. Cylindroniscus platoi n. sp. is regarded as an endemic troglobite based on its limited distribution and on non-obvious troglomorphisms found on its body surface.

A synopsis of centipedes in Brazilian caves: hidden species diversity that needs conservation (Myriapoda, Chilopoda).

This study revises centipede fauna found in Brazilian caves, focusing on troglomorphic taxa and emphasizing conservation status. We present 563 centipede specimens from 274 caves across eleven Brazilian states. Of these, 22 records were derived from existing literature and 252 are newly collected. Specimens represent four orders, ten families, 18 genera, and 47 morphospecies. Together, the cave records represent 21 % of Brazil's centipede fauna. Scolopendromorpha was the most representative order (41 %), followed by Geophilomorpha (26 %), Scutigeromorpha (23 %), and Lithobiomorpha (10 %). Six species were found only in caves, with four considered troglobitic. The distribution of Cryptops iporangensis, the first Brazilian troglobitic centipede species to be discovered, was expanded to other three caves. Cryptops spelaeoraptor and Cryptops iporangensis are two troglobitic species considered Vulnerable and Endangered, respectively, according to the IUCN Red List. Main threats to Brazilian caves are mining, hydroelectric projects, water pollution, and unregulated tourism.

Brazilian obligatory subterranean fauna and threats to the hypogean environment.

The subterranean environment harbors species that are not capable of establishing populations in the epigean environment, i.e., the obligatory subterranean species. These organisms live in a unique selective regime in permanent darkness and usually low food availability, high air humidity in terrestrial habitats, and low temperature range allied to other unique conditions related to lithologies and past climatic influences. The pressure to increase Brazil's economic growth relies on agricultural/pastoral industries and exporting of raw materials such as iron, limestone, ethanol, soybean, cotton, and meat, as well as huge reservoir constructions to generate electricity. Mining (even on a small scale), agricultural expansion, and hydroelectric projects are extremely harmful to subterranean biodiversity, via the modification and even destruction of hypogean habitats. The Brazilian subterranean species were analyzed with respect to their distributions, presence on the IUCN Red List, and current and potential threats to hypogean habitats. A map and three lists are presented, one with the described obligatory subterranean species, one with undescribed taxa, and one with the current and potential threats to the hypogean environment. To date, 150 obligatory subterranean species have been recorded in Brazil, plus at least 156 undescribed troglomorphic taxa, totaling 306 Brazilian troglobites/obligatory cave fauna. We also analyzed the current and potential cave threats and the conservation actions that are underway to attempt to compensate for loss of these habitats. In according to the Brazilian legislation (Decree 6640) only caves of maximum relevance are fully protected. One strategy to protect the subterranean fauna of Brazil is the inclusion of these species in the IUCN Red List (one of attributes that determines maximum relevance for caves); however, one of the IUCN assumptions is that the taxa must be formally described. It is clear that the description and proposed protection of Brazilian subterranean biodiversity depends on more systematics studies.

A new species of cave dwelling Neocarus (Acari: Opilioacaridae) from Bahia state, Brazil, with remarks on taxonomic characters.

Neocarus coronatus n. sp., is described from caves and the surrounding epigean habitats from a karst area of São Desidério county, Bahia state, Brazil. A dissection procedure is presented for the better use of scarce Opilioacaridae material, especially to analyze gut contents. Sexual dimorphism is presented, mainly differences in the density of setae on the dorsal shield in the prominent triangular anterior region. Females have an ovipositor with 3 pairs of smooth digitiform projections and 6-8 eugenital setae. Adults have a palpal tibiotarsus with 4 d setae. Using Low-Temperature Scanning Electron Microscopy (LT-SEM), evaluation of the chaetotaxy (especially setal shape) and morphology are greatly improved over standard light microscopy techniques enhancing the interpretation of characters for species differentiation. Also, we discuss the fragility of microinvertebrates in cave habitats.

Influence of substrate on the richness and composition of Neotropical cave fauna.

The food base in the subterranean environment consists mainly of allochthonous materials. In this environment the resources are distributed generally in a heterogeneous dispersed way and the distribution of resources and their availability determine where the terrestrial invertebrates will reside, which is important for understanding ecological relationships and to establish conservation strategies. Thus, we tested how the complexity of substrates influences the richness and composition of the subterranean terrestrial invertebrates in the Presidente Olegário karst area, southeastern Brazil. We carried out collections in six caves during both dry and wet seasons, using combined collection methods. We observed different distributions in relation to the substrate, because the environmental heterogeneity increases the amount of available niches for the fauna. Some taxa showed a preference for specific substrates, probably related to the availability of food resources and humidity and to body size restriction, emphasizing the niche differentiation between species. Anthropogenic impacts can cause irreversible alterations in the subterranean fauna because the subterranean environment is dependent on the surface for input of trophic resources. On-going impacts in the Presidente Olegario karst area, like agriculture, pastures, gas extraction, and hydroelectric projects, are therefore a serious threat to subterranean biodiversity and this region should be prioritized for conservation.

Influence of substrate on the richness and composition of Neotropical cave fauna

ABSTRACT The food base in the subterranean environment consists mainly of allochthonous materials. In this environment the resources are distributed generally in a heterogeneous dispersed way and the distribution of resources and their availability determine where the terrestrial invertebrates will reside, which is important for understanding ecological relationships and to establish conservation strategies. Thus, we tested how the complexity of substrates influences the richness and composition of the subterranean terrestrial invertebrates in the Presidente Olegário karst area, southeastern Brazil. We carried out collections in six caves during both dry and wet seasons, using combined collection methods. We observed different distributions in relation to the substrate, because the environmental heterogeneity increases the amount of available niches for the fauna. Some taxa showed a preference for specific substrates, probably related to the availability of food resources and humidity and to body size restriction, emphasizing the niche differentiation between species. Anthropogenic impacts can cause irreversible alterations in the subterranean fauna because the subterranean environment is dependent on the surface for input of trophic resources. On-going impacts in the Presidente Olegario karst area, like agriculture, pastures, gas extraction, and hydroelectric projects, are therefore a serious threat to subterranean biodiversity and this region should be prioritized for conservation.