Two new species of the genus Otacilia Thorell 1897 are described from the Vang Vieng Karst in northwestern Laos: O. tham spec. nov., the first species of the entire family that lives in caves and is ...blind, i.e. has only non-functional remnants of the four lateral eyes, and O. saszykaska spec. nov., a cave-dwelling species with eight eyes, and posterior median eyes strongly reduced in size. A distribution map of E- and SEAsian genera of Phrurolithidae is provided.
Abstract
Diplurans (Hexapoda) are considered the ‘ideal cavernicolous animal’ having one of the highest ratios of cave-adapted vs. non-cave-adapted species. They are successful colonizers of ...subterranean habitats, thriving in all cryptic, dark, terrestrial environments. Diplurans play an important role in the decomposition of organic matter below the ground and are sensitive to anthropogenic pressures. We present the first comprehensive review about cave Diplura diversity, ecology, evolution, distribution and biogeography. We provide a roadmap for research questions regarding the ecology, aimed at stimulating the pursuit of new studies on this fascinating group. Filling these current knowledge gaps will contribute to conservation efforts for cave ecosystems.
Four new species of the genus
Redikorzev, 1938 are described from caves in the provinces of Tak (
and
), Chiangmai (
), and Nakhon Ratchasima (
). An identification key is provided to all known world ...representatives of the genus
.
The species Masirana glabra (Komatsu 1957) is redescribed based on fresh specimens collected in the type locality, 65 years after its original description. The female is recorded and described for ...the first time. Habitus and genitalia of both sexes are illustrated in detail and the DNA barcode of the species is provided. Additional notes on the ecology of the species are reported. Our morphological and ecological observations further support M. glabra as a true troglobiont.
A redescription of the genus Antrosedes Reitter, 1912 is given. An identification key for both species of the genus, as well as data on their distribution is provided.
During 2010–2012 the diversity and distribution patterns of Collembola were surveyed in 28 karst and pseudokarst caves of the Western Carpathians, Slovakia. In total 90 species were recorded, 18 of ...which were closely associated with caves (eutroglophiles), obligate cave forms (troglobionts) were represented by 13 species assigned to the genera Pseudosinella (5), Deuteraphorura (3), Megalothorax (2), Protaphorura (1), Pygmarrhopalites (1) and Neelus (1). Cave entrance elevation, internal air temperature and geographic location played an important role in the distribution of cave Collembola. Species diversity was positively correlated with internal air temperature and negatively with cave elevation and latitude. Non‐metric multidimensional scaling (NMS), cluster and indicator value (IndVal) analyses showed that communities of cave Collembola display a clear geographic pattern in the Western Carpathians. The Slovak and Aggtelek Karst and adjacent areas in the south‐eastern part of the Western Carpathians have higher species diversity and number of troglobionts in contrast with karst areas of the central part that have only a few obligate cave forms. Northern karst areas are obviously less diverse and troglomorphic taxa are absent there. The study supports the idea that southern and central karst units of the Western Carpathians might represent important glacial refugia for subterranean fauna.
Aim
To disentangle the role of evolutionary history, competition and environmental filtering in driving the niche evolution of four closely related subterranean spiders, with the overarching goal of ...obtaining a mechanistic description of the factors that determine species' realized distribution in simplified ecological settings.
Location
Dinaric karst, Balkans, Europe.
Taxon
Dysderidae spiders (Stalita taenaria, S. pretneri, S. hadzii and Parastalita stygia).
Methods
We resolved phylogenetic relationships among species and modelled each species' distribution using a set of climatic and habitat variables. We explored the climatic niche differentiation among species with n‐dimensional hypervolumes and shifts in their trophic niche using morphological traits related to feeding specialization.
Results
Climate was the primary abiotic factor explaining our species' distributions, while karstic and soil features were less important. Generally, there was a high niche overlap among species, reflecting their phylogenetic relatedness, but on a finer scale, niche shifts explained the realized distribution patterns. Trophic interaction was another important factor influencing species distributions – the non‐overlapping distributions of three morphologically indistinguishable Stalita species is seemingly the outcome of competitive exclusion dynamics. The distribution of the fourth species, Parastalita stygia, overlaps with that of the other species, with several instances of coexistence within caves. As inferred from the morphology of the mouthparts, the mechanism that minimizes interspecific competition is the shift in the trophic niche of P. stygia towards a more specialized diet.
Main conclusions
We showed that similarity in niches only partly correlated with the phylogenetic distance among species, and that overlaps in species distributions are possible only when a parallel shift in diet occurs. Our work emphasized how even simplified environments still maintain the potential for diversification via niche differentiation. Ultimately, we provide an ecological explanation for the diversification of life in an important hotspot of subterranean diversity.
Aim
Quantifying the relative contribution of environmental filtering versus limiting similarity in shaping communities is challenging because these processes often act simultaneously and their effect ...is scale‐dependent. Focusing on caves, island‐like natural laboratories with limited environmental variability and species diversity, we tested: (i) the relative contribution of environmental filtering and limiting similarity in determining community assembly in caves; (ii) how the relative contribution of these driving forces changes along environmental gradients.
Location
Europe.
Time period
Present.
Major taxa studied
Subterranean spiders.
Methods
We used data on distribution and traits for European cave spiders (n = 475 communities). We estimated the trait space of each community using probabilistic hypervolumes, and obtained estimations of functional richness independent of the species richness of each community via null modelling. We model functional diversity change along environmental gradients using generalized dissimilarity modelling.
Results
Sixty‐three percent of subterranean spider communities exhibited a prevalence of trait underdispersion. However, most communities displayed trait dispersion that did not depart significantly from random, suggesting that environmental filtering and limiting similarity were both exerting equally weak or strong, yet opposing influences. Overdispersed communities were primarily concentrated in southern latitudes, particularly in the Dinaric karst, where there is greater subterranean habitat availability. Pairwise comparisons of functional richness across caves revealed these effects to be strongly scale‐dependent, largely varying across gradients of cave development, elevation, precipitation, entrance size and annual temperature range. Conversely, geographical distance weakly affected trait composition, suggesting convergence in traits among communities that are far apart.
Main conclusions
Even systems with stringent environmental conditions maintain the potential for trait differentiation, especially in areas of greater habitat availability. Yet, the relative influence of environmental filtering and limiting similarity change with scale, along clear environmental gradients. The interplay of these processes may explain the assembly of species‐poor subterranean communities displaying high functional specialization.
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