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.     

Restored meadow harvestman communities (Opiliones) in the Bílé Karpaty Protected Landscape Area, Czech Republic

Harvestman communities inhabiting plots treated differently for grassland restoration were investigated at the Vyzkum site near Malá Vrbka village (Bílé Karpaty Protected Landscape Area). Harvestman were sampled by pitfall trapping from 1999 to 2003 on plots sown with native haymeadow seed mixture, also on plots where narrow strips of regional seed mixtures were sown either within a matrix of commercial grass mixture or within vegetation cover in natural regeneration state and on plots in a natural regeneration state. Additionally, harvestman were collected in a field under permanent crop rotation and in a neighbouring xerothermic deciduous forest. In total, 5,086 individuals of harvestman representing 15 species from three families were obtained. Phalangium opilio was dominant (78%) and P. opilio, Rilaena triangularis and Zachaeus crista were the most frequent species. The results confirmed colonisation and subsequent development of harvestman communities on meadows in various state of restoration, including plots with spontaneous plant succession. Nevertheless, biotope character and successive formation of plant cover evidently influenced the structure of harvestman communities. The highest number of taxa (12) was recorded on plots with natural regeneration; the lowest one (9) was recorded in the field with permanent crop rotation. The highest values of diversity and equitability indices of harvestman communities were found in neighbouring forest habitats representing possible sources of harvestman migration.     

Evolutionary conservation and versatility of a new set of primers for amplifying the ribosomal internal transcribed spacer regions in insects and other invertebrates

The evolutionary conservation and versatility of a new set of nuclear primers for the amplification of the ribosomal internal transcribed spacer regions in insects and other invertebrates have been studied. These primers, conserved across Insecta and other invertebrates, are based on a comprehensive taxonomic survey of the current DNA sequence databases. Their versatility was demonstrated by extensive polymerase chain reaction assays in 16 species from two arachnid orders, eight insect orders, three invertebrate and vertebrate chordate orders and by direct sequencing of the amplified products. The availability of these primers to the insect research community should facilitate the use of internal transcribed spacer regions in intraspecific studies as well as phylogenetic analysis of closely related taxa.     

Morphology of locomotor appendages in Arachnida: evolutionary trends and phylogenetic implications

The morphological diversity of locomotor appendages in Arachnida is surveyed lo reconstruct phylogenetic relationships and discover evolutionary trends in form and function. The appendicular skeleton and musculature of representatives from the ten living arachnid orders ate described, and a system of homology is proposed. Character polarities are established through comparison with an outgroup. Limulus polyphemus Xiphosura). Cladistic analysis suggests that Arachnida is monophyletic and that absence of extensor muscles is a primitive condition. Extensors are primitively absent in Araneae. Amblypygi, Uropygi, Palpigradi, Ricinulei and Acari. Most similarities in the appendages of these orders are symplesiomorphic so that phylogenetic relationships among the 'extensorless' groups cannot be resolved solely on the basis of appendicular characters. Extensor muscles appear to have evolved once, and their presence is considered a synapomorphic feature of Opiliones, Scorpiones, Pseudoscorpiones and Solifugae. Solifugae lack extensors, but a parsimonious interpretation of other characters indicates that this is a secondary, derived condition. The phylogenetic relationships among these four orders are clarified by modifications of the patellotibial joint. Cladistic analysis indicates that Opiliones may be the sister group of the other three orders and that Scorpiones is the sister group of Pseudoscorpiones and Solifugae. Conclusions concerning phylogenetic relationships and evolutionary morphology presented here differ substantially from those of earlier studies on the locomotor appendages of Arachnida.     

The accoutrements of spiders' eggs (Araneae) with an exploration of their functional importance

Analysis is presented of the characteristics of spheres coating the chorion surface of the eggs from 41 species belonging to 15 families of spiders. Examples of eggs from the arachnid orders Opiliones, Amblypygi and Uropygi are illustrated for the first time. The spheres are unique, among arachnids, to the Araneae. Their form and size class distributions overlap considerably between families and the spheres are present in all 22 families of Araneae that have been examined; they represent a very conservative morphological feature in the evolution of the Araneae. Evidence of specialized regions of the egg surface (micropyllar areas and plastrons) was found only in an opilionid. As spiders' eggs are laid in silk egg sacs, mostly in clutches, the possible effects of these characteristics are discussed from evidence in the literature and from a functional theoretic stance.     

中国南方四种跳蛛（蛛形纲：蜘蛛目）

本文记述采自我国云南、湖南两省的４种跳蛛。其中有两个新种：双屏八氏跳蛛Ｙａｇｉｎｕｍａｅｌｌａ ｂｉｌａｇｕｎｃｕｌａ ｓｐ．ｎｏｖ．和南岳八氏跳蛛Ｙａｇｉｎｕｍａｅｌｌａ ｎａｎｙｕｅｎｓｉｓ ｓｐ．ｎｏｖ．;２个新记录种是：直管胶跳蛛Ｇｅｌｏｔｉａ ｓｙｒｉｎｇｏｐａｌｐｉｓ Ｗａｎｌｅｓｓ,１９８４和山地八氏跳蛛Ｙａｇｉｎｕｍａｅｌｌａｍｏｎｔａｎａ Ｚａｂｋａ,１９８１。胶跳蛛属Ｇｅｌｏｔ     

Cooperation in the neotropical pseudoscorpion, <Emphasis Type="Italic">Paratemnoides nidificator</Emphasis> (Balzan, 1888): feeding and dispersal behavior

Social behavior is rare among arachnids, and “permanent-sociality” is a strategy documented only in a few spider species. Here we describe the feeding and dispersal behavior of Paratemnoides nidificator, a Neotropical pseudoscorpion presenting “non-territorial permanent-sociality”. Field and laboratory observations (100 hours and 200 sessions over four years) and manipulative experiments revealed that P. nidificator is a generalist predator that lives in rough bark of trees, in groups of 2 to 175 individuals (42.62 ± 28.27; N=35 colonies; solitary individuals were never found), including reproductive adults and nymphs. Individuals in groups cooperatively capture prey four times larger than solitary individuals. Adult hunters share food with siblings. Reproduction in natural conditions occurs during the hot/wet season, when food availability is high. Prey diversity and abundance seem to be the main factor limiting reproduction in this species. Phoresy (attachment to a transporter animal) is the basic mode of dispersion in P. nidificator. Grouped individuals use large animals as vectors for dispersal, and once established they use the vector as the first food item of the new colony. However, they can also disperse by colony fission, newly documented herein for this taxon. The elaborate, cooperative behavior in P. nidificator is unique among pseudoscorpions and represents an excellent model for studies on the evolution of sociality in invertebrates. Received 10 August 2006; revised 17 November 2006; accepted 23 January 2007.     

Taking the discovery approach in integrative taxonomy: decrypting a complex of narrow‐endemic Alpine harvestmen (Opiliones: Phalangiidae: Megabunus)

Species delimitation is fundamental for biological studies, yet precise delimitation is not an easy task, and every involved approach has an inherent failure rate. Integrative taxonomy, a method that merges multiple lines of evidence, can profoundly contribute to reliable alpha‐taxonomy and shed light on the processes behind speciation. In this study, we explored and validated species limits in a group of closely related Megabunus harvestmen (Eupnoi, Phalangiidae) endemic to the European Alps. Without a priori species hypotheses, we used multiple sources of inference, including mitochondrial and multilocus nuclear DNA, morphometrics and chemistry. The results of these discovery approaches revealed morphological crypsis and multiple new species within two of the five hitherto known species. Based on our analyses, we discussed the most plausible evolutionary scenarios, invoked the most reasonable species hypotheses and validated the new species limits. Building upon the achieved rigour, three new species, Megabunus cryptobergomas Muster and Wachter sp. nov., Megabunus coelodonta Muster and Steiner sp. nov., and Megabunus lentipes Muster and Komposch sp. nov., are formally described. In addition, we provide a dichotomous morphological key to the Megabunus species of the Alps. Our work demonstrates the suitability of integrative, discovery‐based approaches in combination with validation approaches to precisely characterize species and enabled us to implement nomenclatural consequences for this genus.     

Proximate factors and potential benefits influencing selection of Psychotria suterella for shelter by the harvestman Jussara spec.

Harvestmen (Arachnida, Opiliones) are arachnids that rely on chemicals for communication and are particularly dependent on high humidity. The harvestman Jussara spec. (Sclerosomatidae) clearly prefers to rest on the stem and leaves of Psychotria suterella Muell. Arg. (Rubiaceae), a plant having a complex architecture of overlapping branches. So far, few studies have focused on understanding how harvestmen find their host plant and the benefits associated with the selected plant. Here, we investigated cues harvestmen may exploit to find P. suterella and the potential benefits for harvestmen of this interaction. To address how harvestmen find the plant, we tested two non‐exclusive hypotheses: harvestmen use chemicals from conspecifics, and/or harvestmen use chemicals from plants. For the first hypothesis, we assessed the number of harvestmen choosing P. suterella with or without chemicals of Jussara spec. on the main stem. We did not find evidence that Jussara spec. uses chemicals from conspecifics to select P. suterella, at least in isolation, without any mechanical stimuli such as stem texture or size. For the second hypothesis, we tested harvestman behavior exposed to volatiles from P. suterella, a non‐preferred host plant – Impatiens walleriana Hook.f. (Balsaminaceae) – and a blank treatment, both in a triangular arena and in a Y‐tube olfactometer. We also found no evidence that the harvestmen use plant volatiles to find it. We also tested two non‐exclusive hypotheses regarding the benefits of selecting P. suterella for harvestmen. The first hypothesis is that P. suterella offers a higher humidity than other plants in the micro‐environment surrounding the leaves because of a high leaf transpiration rate. Harvestmen could benefit from this because they rest with the body in contact with the leaf or at less than 5 mm from it. We did not find evidence that leaf transpiration rate is important for Jussara spec., as P. suterella did not present high rates compared to other local species. The second hypothesis is that the leaves of P. suterella provide a better shadow than other plants, acting as a sun shade due to its complex architecture with overlapping leaves. We measured light passage through the leaves of P. suterella and three other local species and found that less light passes through the leaves of P. suterella, which therefore provides darker shadow. This potentially provides a favorable micro‐climate for harvestmen, which might help to explain the micro‐habitat preference of Jussara spec.