Aim To test the hypothesis that continental drift drives diversification of organisms through vicariance, we selected a group of primitive arachnids which originated before the break‐up of Pangaea and currently inhabits all major landmasses with the exception of Antarctica, but lacks the ability to disperse across oceanic barriers. Location Major continental temperate to tropical landmasses (North America, South America, Eurasia, Africa, Australia) and continental islands (Bioko, Borneo, Japan, Java, New Caledonia, New Guinea, New Zealand, Sri Lanka, Sulawesi, Sumatra). Methods Five kb of sequence data from five gene regions for more than 100 cyphophthalmid exemplars were analysed phylogenetically using different methods, including direct optimization under parsimony and maximum likelihood under a broad set of analytical parameters. We also used geological calibration points to estimate gross phylogenetic time divergences. Results Our analyses show that all families except the Laurasian Sironidae are monophyletic and adhere to clear biogeographical patterns. Pettalidae is restricted to temperate Gondwana, Neogoveidae to tropical Gondwana, Stylocellidae to Southeast Asia, and Troglosironidae to New Caledonia. Relationships between the families inhabiting these landmasses indicate that New Caledonia is related to tropical Gondwana instead of to the Australian portion of temperate Gondwana. The results also concur with a Gondwanan origin of Florida, as supported by modern geological data. Main conclusions By studying a group of organisms with not only an ancient origin, low vagility and restricted habitats, but also a present global distribution, we have been able to test biogeographical hypotheses at a scale rarely attempted. Our results strongly support the presence of a circum‐Antarctic clade of formerly temperate Gondwanan species, a clade restricted to tropical Gondwana and a Southeast Asian clade that originated from a series of early Gondwanan terranes that rifted off northwards from the Devonian to the Triassic and accreted to tropical Laurasia. The relationships among the Laurasian species remain more obscure.
We investigate the phylogeny, biogeography, time of origin and diversification, ancestral area reconstruction and large‐scale distributional patterns of an ancient group of arachnids, the harvestman suborder Cyphophthalmi. Analysis of molecular and morphological data allow us to propose a new classification system for the group; Pettalidae constitutes the infraorder Scopulophthalmi new clade, sister group to all other families, which are divided into the infraorders Sternophthalmi new clade and Boreophthalmi new clade. Sternophthalmi includes the families Troglosironidae, Ogoveidae, and Neogoveidae; Boreophthalmi includes Stylocellidae and Sironidae, the latter family of questionable monophyly. The internal resolution of each family is discussed and traced back to its geological time origin, as well as to its original landmass, using methods for estimating divergence times and ancestral area reconstruction. The origin of Cyphophthalmi can be traced back to the Carboniferous, whereas the diversification time of most families ranges between the Carboniferous and the Jurassic, with the exception of Troglosironidae, whose current diversity originates in the Cretaceous/Tertiary. Ancestral area reconstruction is ambiguous in most cases. Sternophthalmi is traced back to an ancestral land mass that contained New Caledonia and West Africa in the Permian, whereas the ancestral landmass for Neogoveidae included the south‐eastern USA and West Africa, dating back to the Triassic. For Pettalidae, most results include South Africa, or a combination of South Africa with the Australian plate of New Zealand or Sri Lanka, as the most likely ancestral landmass, back in the Jurassic. Stylocellidae is reconstructed to the Thai‐Malay Penisula during the Jurassic. Combination of the molecular and morphological data results in a hypothesis for all the cyphophthalmid genera, although the limited data available for some taxa represented only in the morphological partition negatively affects the phylogenetic reconstruction by decreasing nodal support in most clades. However, it resolves the position of many monotypic genera not available for molecular analysis, such as Iberosiro, Odontosiro, Speleosiro, Managotria or Marwe, although it does not place Shearogovea or Ankaratra within any existing family. The biogeographical data show a strong correlation between relatedness and formerly adjacent landmasses, and oceanic dispersal does not need to be postulated to explain disjunct distributions, especially when considering the time of divergence. The data also allow testing of the hypotheses of the supposed total submersion of New Zealand and New Caledonia, clearly falsifying submersion of the former, although the data cannot reject the latter. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 92–130.
The hitherto monotypic opilionid genus Fangensis Rambla, 1994 is re-evaluated from new material collected in northern, western and southern Thailand. The original description of F. leclerci Rambla (type material not traceable) was based on specimens belonging to at least three distinct species. Fangensis leclerci is thus redefined and the binomen restricted to specimens from a cave in northern Thailand only. Three new species are described, F. spelaeus, sp. nov. and F. cavernarus, sp. nov. from two caves in western Thailand and F. insulanus, sp. nov. from forests on two islands in southern Thailand. Taxonomic characters are discussed and relationships among Fangensis species and between Fangensis and other cyphophthalmids are evaluated using morphological data and ~4 Kb of molecular data from three loci, two nuclear ribosomal genes and a mitochondrial coding gene. Overall, data indicate monophyly of Stylocellidae and morphological and ribosomal data suggest monophyly of Fangensis, which is in turn divided into two clades, one composed of the three species from northern and western Thailand and the other represented by the species from southern Thailand. Observations on mating in F. leclerci are provided.
Introduction Nonunion is a common complication after intramedullary nailing of subtrochanteric femoral fractures. A more detailed knowledge, particularly of avoidable risk factors for subtrochanteric fracture nonunion, is thus desired to develop strategies for reducing nonunion rates. The aim of the present study therefore was to analyse a wide range of parameters as potential risk factors for nonunion after intramedullary nailing of subtrochanteric fractures. Materials and methods Seventy-four patients who sustained a subtrochanteric fracture and were treated by femoral intramedullary nailing at a single level 1 trauma centre within a 6-year period were included in this study. A total of 15 patient-related, fracture-related, surgery-related, mechanical and biological parameters were analysed as potential risk factors for nonunion. Furthermore, the accuracy of each of these parameters to predict nonunion was calculated. Results Nonunion occurred in 17 of 74 patients (23.0%). Of the 15 potential risk factors analysed, only 3 were found to have a significant effect on the nonunion rate ( p < 0.05): postoperative varus malalignment, postoperative lack of medial cortical support and autodynamisation of the nail within the first 12 weeks post-surgery. Accuracy of each of these 3 parameters to predict nonunion was > 0.70. Furthermore, the nonunion rate significantly increased with the number of risk factors (no risk factor: 2.9%, one risk factor: 23.8%, two risk factors: 52.9%, and three risk factors: 100% [Chi-square test, p = 0.001)]. Conclusions Our study indicates that intraoperative correction of varus malalignment and restoration of the medial cortical support are the most critical factors to prevent nonunion after intramedullary nailing of subtrochanteric femoral fractures. In addition, autodynamisation of the nail within the first 3 months post-surgery is a strong predictor for failure and should result in revision surgery.
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