Macroecologists seek to identify drivers of community turnover ( β -diversity) through broad spatial scales. However, the influence of local habitat features in driving broad-scale β -diversity patterns remains largely untested, owing to the objective challenges of associating local-scale variables to continental-framed datasets. We examined the relative contribution of local- versus broad-scale drivers of continental β -diversity patterns, using a uniquely suited dataset of cave-dwelling spider communities across Europe (35–70° latitude). Generalized dissimilarity modelling showed that geographical distance, mean annual temperature and size of the karst area in which caves occurred drove most of β -diversity, with differential contributions of each factor according to the level of subterranean specialization. Highly specialized communities were mostly influenced by geographical distance, while less specialized communities were mostly driven by mean annual temperature. Conversely, local-scale habitat features turned out to be meaningless predictors of community change, which emphasizes the idea of caves as the human accessible fraction of the extended network of fissures that more properly represents the elective habitat of the subterranean fauna. To the extent that the effect of local features turned to be inconspicuous, caves emerge as experimental model systems in which to study broad biological patterns without the confounding effect of local habitat features.
Diplura is a group of entognathous hexapods, often considered a sister group to insects. They play an important role in recycling organic matter in soil and subterranean terrestrial ecosystems. The Campodeidae is the most diverse family, divided into four subfamilies. The subfamily Plusiocampinae has a subterranean life-style with many species distributed in the Euro-Mediterranean area. The incertae sedis tachycampoids (“lignée Tachycampoïde”) is a group within the family Campodeidae that share with the Plusiocampinae a strong preference for subterranean habitats and several morphological characters, such as slender body shape, elongated appendages, considerable increment in the number of antennomeres and cercal articles, and complexity of sensorial structures. The present monograph provides a taxonomic revision of the subfamily Plusiocampinae and the genera belonging to the tachycampoid lineage from Europe and the Mediterranean region. It comprises detailed morphological descriptions and illustrations together with data on the habitats and distributions of 87 species, 10 subspecies and 11 affinis forms. Seven new species are described among those, namely: Plusiocampa (Plusiocampa) apollo Sendra, Giachino & Vailati sp. nov., P. (P.) chiosensis Sendra & Gasparo sp. nov., P. (P.) dublanskii Sendra & Turbanov sp. nov., P. (P.) hoffmanni Sendra & Paragamian sp. nov., P. (P.) rhea Sendra sp. nov., P. (P.) ternovensis Sendra & Borko sp. nov. and P. (Venetocampa) ferrani Sendra & Delić sp. nov.
The spider genus Dysdera is a species‐rich clade of specialized woodlice predators, composed typically of complexes of sibling species. Here, we analyse the Dysdera ninnii complex, distinguishing three species that exhibit slight but constant differences in the morphology of their copulatory organs, and in their genetic background. We designate a neotype for D. ninnii and redescribe it. We consider Dysdera pavesii Thorell, 1873 to be a junior synonym of Dysdera ninnii Canestrini, 1868. In addition, we describe two new species (Dysdera moravica sp. nov. and Dysdera microdonta sp. nov.). All three species occur in the region of north‐eastern Italy, Slovenia, and north‐western Croatia. Dysdera moravica sp. nov. expanded to central Europe. The species occur allopatrically or parapatrically. All three species possess the same diploid number and X0 sex chromosome determination. In some individuals we found chromosome fusions, and such polymorphism is common in spiders with holokinetic chromosomes. The analysis of mitochondrial (cytochrome c oxidase subunit I, COI) and nuclear ribosomal (internal transcribed spacer 2, ITS2) DNA markers revealed two clades, one formed by D. ninnii and D. microdonta sp. nov., and a second by D. moravica sp. nov. Species of the first clade are not well defined by DNA markers. We noticed only weak separation of maternally inherited COI, and even overlap of autosomally inherited ITS2 sequences. We suggest that either short speciation time, unfinished lineage sorting, or rare hybridization events caused this pattern. In one sample of D. microdonta sp. nov. we detected the coxA gene of a Rickettsia species, which is the first record of this parasitic bacteria from the spider family Dysderidae. Dysdera microdonta sp. nov. occurs at higher altitudes than D. ninnii, and their distribution ranges form a long contact zone. Remarkably, we did not record any overlap of the two distribution ranges, suggesting that the lack of a precopulatory interspecific barrier causes a loss of reproduction potential. We hypothesize that because of the unsolved interspecific barrier together with only tiny differences in morphology and COI sequences, and no differences in karyotypes and ITS2 sequences, the D. ninnii species complex is evolutionarily young. © 2014 The Linnean Society of London
Spiders (Arachnida: Araneae) are widespread in subterranean ecosystems worldwide and represent an important component of subterranean trophic webs. Yet, global-scale diversity patterns of subterranean spiders are still mostly unknown. In the frame of the CAWEB project, a European joint network of cave arachnologists, we collected data on cave-dwelling spider communities across Europe in order to explore their continental diversity patterns. Two main datasets were compiled: one listing all subterranean spider species recorded in numerous subterranean localities across Europe and another with high resolution data about the subterranean habitat in which they were collected. From these two datasets, we further generated a third dataset with individual geo-referenced occurrence records for all these species. Data from 475 geo-referenced subterranean localities (caves, mines and other artificial subterranean sites, interstitial habitats) are herein made available. For each subterranean locality, information about the composition of the spider community is provided, along with local geomorphological and habitat features. Altogether, these communities account for > 300 unique taxonomic entities and 2,091 unique geo-referenced occurrence records, that are made available via the Global Biodiversity Information Facility (GBIF) (Mammola and Cardoso 2019). This dataset is unique in that it covers both a large geographic extent (from 35° south to 67° north) and contains high-resolution local data on geomorphological and habitat features. Given that this kind of high-resolution data are rarely associated with broad-scale datasets used in macroecology, this dataset has high potential for helping researchers in tackling a range of biogeographical and macroecological questions, not necessarily uniquely related to arachnology or subterranean biology.
Sardinia is the second largest island in the Mediterranean and, together with Corsica and nearby mainland areas, one of the top biodiversity hotspots in the region. Th e origin of Sardinia goes back to the opening of the western Mediterranean in the late Oligocene. Th is geological event and the subsequent Messinian Salinity Crisis and Pleistocene glacial cycles have had a major impact on local biodiversity. Th e Dysdera woodlouse hunter spiders are one of the most diverse ground-dweller groups in the Mediterranean. Here we describe the fi rst two species of this genus endemic to Sardinia: Dysdera jana sp. n. and Dysdera shardana sp. n. Th e two species show contrasting allopatric distribution: D. jana sp. n. is a narrow endemic while D. shardana sp. n. is distributed throughout most of the island. A multi-gene DNA sequence phylogenetic analysis based on mitochondrial and nuclear genes supports the close relationships of the new species to the type species of the genus Dysdera erythrina. Age estimates reject an Oligocene origin of the new Dysdera species and identify the Messinian Salinity Crises as the most plausible period for the split between Sardinian endemics and their closest relatives. Phylogeographic analysis reveals deep genetic divergences and population structure in Dysdera shardana sp. n., suggesting that restriction to gene fl ow, probably due to environmental factors, could explain local speciation events.
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