Macrothele

Abstract: The family Hexathelidae is newly erected. Three subfamilies are recognized: Plesiothelinae, for the monotypic Tasmanian genus Plesiothele; Macrothelinae, confined to Macrothele, Porrhothete and Atrax; and the Hexathelinae include Hexathele, Scotinoecus, Bymainiella, Paraembolides, gen. nov. and Terania, gen. nov. The synapomorphic character required for group membership is numerous labial cuspules. Using the size of the anterior lateral spinnerets, the development of megaspines on the first tibia of males, the paraembolic apophysis, and shape of the labium and other characters, the evolution of subfamilies, genera and some species is discussed using Hennigian principles. A biogeographic hypothesis is proposed using the vicariance events of Plate Tectonic theory. The sister group of the Hexathelidae is the Dipluridae, and the sister group of both is the Mecicobothriidae. The subfamily Ischnothelinae is erected to receive those genera of the traditional Macrothelinae that have no labial cuspules.

Abstract: Aim We tested the competing hypotheses concerning the relative importance of Pleistocene versus Miocene–Pliocene geological events for the formation of endemism in an Asian archipelago using the Macrothele taiwanensis (Hexathelidae) species group. Location Taiwan-Ryukyu Archipelago. Methods We estimated phylogenetic trees from cytochrome oxidase I subunit (COI) and 16S rRNA (16S) gene regions and employed Bayesian ancestral range reconstructions to investigate previously debated models of lineage diversification in the Taiwan-Ryukyu Archipelago. To evaluate alternative geological timeframes for their importance in shaping the genetic structure of funnel web spiders, we used five time calibration schemes to estimate timing of divergence, infer ancestral distributions, and to reconstruct historical demographic changes in each lineage. We tested taxonomic boundaries with two species delimitation procedures. Results Our results indicate a north-to-south isolation sequence of the M. taiwanensis group: the Amami lineage diverged first, then Yaeyama, and finally the Taiwanese lineages. Divergence time estimation and population demographic change analyses indicate that Pleistocene climate fluctuations minimally impacted the genetic structure of these spiders. Instead, estimated divergence events correspond to Miocene–Pliocene geological events, strongly supporting a much older timeframe for diversification. The results of species delimitation analyses coincide well with morphological differences observed among the island populations, reinforcing inferred species boundaries, and at least three potential cryptic species were statistically detected within Taiwan. Main conclusions Miocene–Pliocene geological events appear to have contributed disproportionately to diversification in the M. taiwanensis species group. The clear association between geographical area, genetic structure and statistical species delimitation strongly supports an interpretation of allopatric speciation. We advocate comparing our results with those derived from additional study organisms with similar life histories to further explore the Miocene–Pliocene diversification hypothesis.

Abstract: The family Hexathelidae ranks among the smaller mygalomorph spider families. Most species are endemic to the Australasian region and the family was traditionally considered an example of a Gondwanan lineage. However, recent studies have cast some doubt on the monophyly of the family. Macrothele is the only genus with an out-of-Gondwana distribution. The bulk of the Macrothele diversity is found in South-east Asia, few species are known from central Africa and two species inhabit Europe: Macrothele calpeiana (Walckenaer, 1805) from the Iberian Peninsula and Macrothele cretica Kulczynski, 1903 endemic to Crete. Here we investigate the origins of the European Macrothele species by means of a multi-locus phylogenetic approach and by inferring the time frame of the diversification of the genus using Bayesian relaxed clock methods. We also provide further insights into the phylogenetic status of the family Hexathelidae. Our results indicate that the diversification of Macrothele traces back to the period of the Gondwana break-up and its present-day distribution most likely reflects the subsequent tectonic plate movements. The two European species were not recovered as sister taxa, suggesting that Macrothele colonised the Mediterranean region twice independently. The polyphyly of the family Hexathelidae is further confirmed and the subfamily Atracinae is identified as the conflicting lineage.

Abstract: Kang Fang, Chih-Chieh Yang, Bor-Wei Lue, Shyh-Hwang Chen and Kuang-Yang Lue (2000) Phylogenetic corroboration of superfamily Lycosoidae spiders (Araneae) as inferred from partial mitochondrial 12S and 16S ribosomal DNA sequences. Zoological Studies 39(2): 107-113. The genetic variations of two cribellate spider families, the Psechridae and Uloboridae, plus ecribellate spider families within the Araneomorphae, were examined by analyzing their partial mitochondrial 12S and 16S rDNA sequences, based on which phylogenetic closeness was tested. Using the Hexathelidae (Macrothele holsti) as an outgroup, the phylogenetic relationships of Lycosoidea superfamily spiders were investigated. The results indicate that cribellate spiders are polyphyletic. The reconstructed tree based on both maximum parsimony and neighbor joining analyses clearly demonstrates that the cribellate spider, Psechridae, is a member of the Lycosoidea clade that is comprised of the Lycosidae, Pisauridae, and Oxyopidae. The study also reaffirms that the cribellate funnel weavers, Psechridae, and orb weavers, Uloboridae, are two distinct lineages. However, the topology within the Lycosoidea clade from our analysis differs from that as inferred by morphological, ecological, and behavioral characteristics.