Review of the cave-dwelling species ofPseudotyrannochthonius Beier (Arachnida: Pseudoscorpiones: Pseudotyrannochthoniidae) from mainland Australia, with description of two troglobitic species

Three new species of dragon pseudoscorpions (Pseudoscorpiones, Pseudotyrannochthoniidae) from China

Three new pseudoscorpions in the family Pseudotyrannochthoniidae are described from China: Allochthoniushispidus sp. nov. from Chongqing (Wushan County), Spelaeochthoniushuanglaoensis sp. nov. from Beijing (Fangshan District), and Spelaeochthoniustuoliangensis sp. nov. from Hebei (Pingshan County). Detailed diagnoses and illustrations of all new species are provided.

A new pseudoscorpion genus (Garypinoidea: Garypinidae) from the Eocene supports extinction and range contraction in the European paleobiota

During the Paleogene, the Holarctic experienced drastic climatic oscillations, including periods of extensive glaciation. These changes had a severe impact on both the flora and fauna causing widespread extinction and range shifts with some taxa retreating to refugia in the Mediterranean Basin. Here we provide evidence for this hypothesis using fossils from the pseudoscorpion family Garypinidae Daday, 1889 (Arachnida: Pseudoscorpiones). This family comprises 21 extant genera from all continents except Antarctica but is restricted to low mid-latitudes (<44°N) in the Northern Hemisphere. We provide the second record of garypinids from the European succinite ambers of the Eocene by describing the first extinct genus in Garypinidae, Baltamblyolpium gen. nov., which includes two species: Baltamblyolpium gizmotum sp. nov. from Baltic amber and Baltamblyolpium grabenhorsti sp. nov. from Bitterfeld amber. The new genus exhibits a morphology that closely resembles Neoamblyolpium Hoff, 1956 from western North America and the genus Amblyolpium Simon, 1898, which is widespread but includes taxa restricted to Mediterranean refugia in Europe. The discovery of a new fossil genus of Garypinidae from Europe confirms that the family was found at more northerly latitudes during the Eocene, however, extinction and range contraction resulted in their present-day relictual distribution in southern Europe like many other lineages that once thrived in the European "Baltic amber forest" of the Eocene.

Evolutionary morphology of coxal musculature in Pseudoscorpiones (Arachnida)

Pseudoscorpions are an ancient and globally distributed lineage of arachnids with more than 4000 species. Despite being present in virtually all terrestrial habitats, their morphology and anatomy has rarely been studied to date, which hampers homology statements both within and between other arachnid orders. All pseudoscorpions share a morphological peculiarity, the fixation of the coxae of all the walking legs. The same morphological condition is seen in certain other arachnid taxa, such as Solifugae or Scorpiones - potential sistergroups of Pseudoscorpiones. To investigate the musculature apparatus of this unusual feature, we reconstructed the musculature in the coxae of walking legs in three species of pseudoscorpions that represent the three major clades within this order. Using micro-computed tomography (μCT), we show that pseudoscorpions have the highest number of coxal muscles amongst the arachnid orders (12 vs. fewer than 10 in others), and that the muscular composition of the first two legs differs from that in the hind legs, correlating with the difference in function, i.e. pulling in the front legs and pushing in the hind legs. Pseudoscorpions are also unique amongst the arachnids in lacking endoskeletal structures (coxal apodeme or costa coxalis) inside the coxae. We observed that within pseudoscorpions, there is a trend towards a reduction of the number of coxal muscles, with the most basal-branching taxon having the highest number and more derived taxa exhibiting lower counts. We hypothesize the muscular ground pattern for Pseudoscorpiones and discuss the evolution of this system by comparing it to the (scanty) data on other arachnids available in the literature.

Selachochthonius naledi sp. nov. (Pseudoscorpiones, Pseudotyrannochthoniidae), a new troglobitic species from South Africa

A new pseudoscorpion species, Selachochthonius naledisp. nov., is herein described. It can be distinguished from the other species of the genus mainly by the absence of eyes, number and morphology of chelal teeth and coxae setae and by the appendices proportions. This new species represents the fourth record for the genus in South Africa. We also provide some ecological remarks of the new species and recommendations for future research.

Climate variability impacts on diversification processes in a biodiversity hotspot: a phylogeography of ancient pseudoscorpions in south-western Australia

The south-western division of Australia is the only biodiversity hotspot in Australia and is well-known for extreme levels of local endemism. Climate change has been identified as a key threat for flora and fauna, but very few data are presently available to evaluate its impact on invertebrate fauna. Here, we derive a molecular phylogeography for pseudoscorpions of the genus Pseudotyrannochthonius that in the south-west are restricted to regions with the highest rainfall. A dated molecular phylogeny derived from six gene fragments is used for biogeographic reconstruction analyses, spatial mapping, environmental niche-modelling, and to infer putative species. Phylogenetic analyses uncover nine clades with mostly allopatric distributions and often small linear ranges between 0.5 and 130 km. Molecular dating suggests that the origins of contemporary diversity fall into a period of warm/humid Palaeogene climates, but splits in the phylogeny coincide with major environmental shifts, such as significant global cooling during the Middle Miocene. By testing several models of historical biogeography available for the south-west, we determine that Pseudotyrannochthonius is an ancient relict lineage that principally follows a model of allopatric speciation in mesic zone refugia, although there are derivations from this model in that some species are older and distribution patterns more complex than expected. Ecological niche models indicate that drier and warmer future climates will lead to range contraction towards refugia of highest rainfall, probably mimicking past variations that have generated high diversity in these areas. Their conservation management will be crucial for preserving the unique biodiversity heritage of the south-west.

Biogeography and speciation of terrestrial fauna in the south-western Australian biodiversity hotspot

The south-western land division of Western Australia (SWWA), bordering the temperate Southern and Indian Oceans, is the only global biodiversity hotspot recognised in Australia. Renowned for its extraordinary diversity of endemic plants, and for some of the largest and most botanically significant temperate heathlands and woodlands on Earth, SWWA has long fascinated biogeographers. Its flat, highly weathered topography and the apparent absence of major geographic factors usually implicated in biotic diversification have challenged attempts to explain patterns of biogeography and mechanisms of speciation in the region. Botanical studies have always been central to understanding the biodiversity values of SWWA, although surprisingly few quantitative botanical analyses have allowed for an understanding of historical biogeographic processes in both space and time. Faunistic studies, by contrast, have played little or no role in defining hotspot concepts, despite several decades of accumulating quantitative research on the phylogeny and phylogeography of multiple lineages. In this review we critically analyse datasets with explicit supporting phylogenetic data and estimates of the time since divergence for all available elements of the terrestrial fauna, and compare these datasets to those available for plants. In situ speciation has played more of a role in shaping the south-western Australian fauna than has long been supposed, and has occurred in numerous endemic lineages of freshwater fish, frogs, reptiles, snails and less-vagile arthropods. By contrast, relatively low levels of endemism are found in birds, mammals and highly dispersive insects, and in situ speciation has played a negligible role in generating local endemism in birds and mammals. Quantitative studies provide evidence for at least four mechanisms driving patterns of endemism in south-western Australian animals, including: (i) relictualism of ancient Gondwanan or Pangaean taxa in the High Rainfall Province; (ii) vicariant isolation of lineages west of the Nullarbor divide; (iii) in situ speciation; and (iv) recent population subdivision. From dated quantitative studies we derive four testable models of historical biogeography for animal taxa in SWWA, each explicit in providing a spatial, temporal and topological perspective on patterns of speciation or divergence. For each model we also propose candidate lineages that may be worthy of further study, given what we know of their taxonomy, distributions or relationships. These models formalise four of the strongest patterns seen in many animal taxa from SWWA, although other models are clearly required to explain particular, idiosyncratic patterns. Generating numerous new datasets for suites of co-occurring lineages in SWWA will help refine our understanding of the historical biogeography of the region, highlight gaps in our knowledge, and allow us to derive general postulates from quantitative (rather than qualitative) results. For animals, this process has now begun in earnest, as has the process of taxonomically documenting many of the more diverse invertebrate lineages. The latter remains central to any attempt to appreciate holistically biogeographic patterns and processes in SWWA, and molecular phylogenetic studies should - where possible - also lead to tangible taxonomic outcomes.