In this paper we describe a new type of subterranean habitat associated with dry watercourses in the Eastern Iberian Peninsula, the “Alluvial Mesovoid Shallow Substratum” (alluvial MSS). Historical observations and data from field sampling specially designed to study MSS fauna in the streambeds of temporary watercourses support the description of this new habitat. To conduct the sampling, 16 subterranean sampling devices were placed in a region of Eastern Spain. The traps were operated for 12 months and temperature and relative humidity data were recorded to characterise the habitat. A large number of species was captured, many of which belonged to the arthropod group, with marked hygrophilous, geophilic, lucifugous and mesothermal habits. In addition, there was also a substantial number of species showing markedly ripicolous traits. The results confirm that the network of spaces which forms in alluvial deposits of temporary watercourses merits the category of habitat, and here we propose the name of “alluvial MSS”. The “alluvial MSS” may be covered or not by a layer of soil, is extremely damp, provides a buffer against above ground temperatures and is aphotic. In addition, compared to other types of MSS, it is a very unstable habitat. It is possible that the “alluvial MSS” may be found in other areas of the world with strongly seasonal climatic regimes, and could play an important role as a biogeographic corridor and as a refuge from climatic changes.

In this study, the invertebrate fauna of a colluvial Mesovoid Shallow Substratum (MSS) is Eastern Spain was characterized, and the importance of the MSS as refuge for endemic and rare species was assessed. Ten pitfall traps were buried up to 1 m deep inside multiperforated PVC tubes across a stone debris. Several environmental variables were measured in each sampling point. The completeness of the inventory was assessed, and different diversity patterns—variation in abundance, species richness and species composition—were analyzed. 4150 individuals and 164 species were captured, most of them arthropods. The number of individuals and species varied considerably among traps. Half of the species were represented by one or two individuals, and neither the species accumulation curves nor the curves for the non-parametric estimators showed any sign of stabilizing. Individuals of abundant species aggregated in one or a few traps. No consistent diversity patterns were found, except that distance among traps partially explained the similarity in species composition when considering only the most abundant species. This is a very rich but uneven assemblage that shows a high degree of species turnover between traps. One-sixth of the species can be classified as either troglobionts or troglophiles, but there is a significant presence of edaphic species. Obtaining complete fauna inventories in the MSS has proven to be a challenging task. The study of the MSS reveals important faunistic information, providing new taxa to science as well as interesting records of poorly known species.

Subsurface biota extends over a wide variety of habitats that can be spatially interconnected. The largest communities of this subsurface biota inhabit cavities and are well known mainly in caves where biologists are able to have access. Data about deep subterranean communities and arthropods living under one thousand meters was unknown. An expedition to world’s deepest cave, Krubera-Voronja in Western Caucasus, revealed an interesting subterranean community, living below 2000 meters and represented by more than 12 species of arthropods, including several new species for science. This deep cave biota is composed of troglobionts and also epigean species, that can penetrate until -2140 m. Deep subterranean ecosystems should not be seen only as an evolutionary dead end towards the troglomorphic syndrome, but also as a shelter for epigean species populations, especially during long periods of time when surface conditions are severe for their survival. Most of the subsurface biota depends on allochthonous sources of organic carbon coming from: water percolating from the surface, sinking streams that enter caves, and activities of animals moving in and out of caves. The biocoenosis and the vertical distribution of invertebrate fauna of Krubera-Voronja are provided, from its entrance to the remarkable depth of 2140 meters, including the discovery of world’s deepest dwelling arthropod.

Twenty-nine specimens of Diplura collected from eight caves in China and Myanmar contain two new genera, Hubeicampa Sendra & Lips gen. nov. and Mueggejapyx Sendra & Komerički gen. nov., as well as four new species, Anisuracampa ywangana Sendra & Komerički sp. nov., Hubeicampa melissa Sendra & Lips gen. et sp. nov., Pacificampa wudonghuii Sendra sp. nov. and Mueggejapyx brehieri Sendra & Komerički gen. et sp. nov. These cave-adapted taxa showcase an impressive diversity in morphological adaptation (troglomorphy) to cave ecosystems. Their sensorial equipment, setae and receptors in the cupuliform organ have unique forms (H. melissa gen. et sp. nov.), as well as the pretarsus sticky surface (A. ywangana sp. nov. and H. melissa gen. et sp. nov.). Recent contributions on Asian diplurans, together with the taxonomic novelties shown in the present study, highlight the biogeographical importance of the Asian biodiversity. Asia is revealed as a continent with vast karst regions still waiting to be explored and new dipluran species waiting to be discovered.

Krubera-Voronya cave and other deep systems in Arabika Massif are being explored during many speleological expeditions. A recent Ibero-Russian exploration expedition (summer of 2010) took place in this cave with the aim of providing a study of the biocenosis of the deepest known cave in the world. Four new species of Collembola were found at different depths:Schaefferia profundissiman. sp.,Anurida stereoodoratan. sp.,Deuteraphorura kruberaensisn. sp., andPlutomurus ortobalaganensisn. sp., the last one at -1980 m deep. The identification and description of the new species have required the careful study of all congeneric species, implying a revision of each genus. As a result of this work tables and keys to all significant characters for each species are presented.