Mattoni, C. I. & L. Prendini, Phylogeny and biogeography of the family Bothriuridae (Scorpiones)

MATTONI, C.I. Y L. PRENDINI

São Pedro, São Paulo, Brasil

Congreso; 17th International Congress of Arachnology (ISA); 2007

International Society for Arachnology

The scorpion family Bothriuridae comprises ca. 130 species in 13 genera, with a Gondwana distribution in South America, southern Africa and Australia. Phylogenetic relationships among the bothriurid genera have been studied previously, but require further investigation in light of recent developments. For example, the monophyly and validity of Brandbergia was recently questioned, and it was synonymized with Lisposoma. The goals of the present study were to (1) test the monophyly of Bothriuridae and determine its phylogenetic placement with respect to other scorpion families; (2) resolve the phylogenetic relationships among and test the monophyly of the bothriurid genera; (3) provide a hypothesis of historical biogeographical events explaining the present distribution of the family in light of the phylogeny. A comprehensive revision of the external and internal morphology was undertaken, which produced more than 280 characters for 42 bothriurid species and 16 outgroups. Phylogenetic analyses were conducted and the support for each group calculated. The monophyly of Bothriuridae, and its placement as sister group of the remaining scorpionoids, were supported. The validity of Brandbergia was confirmed, the genus being placed sister to Lisposoma, and it was reinstated. The monophyly of Brachistosternus, and its current division into three subgenera, were supported. Bothriurus and Orobothriurus were polyphyletic. Vachonia and Timogenes were sister taxa, placed in a group with part of Bothriurus. Tehuankea was closely related to Centromachetes, Pachakutej and some Bothriurus species. The genera presenting the most plesiomorphic characters, Lisposoma, Brandbergia, Cercophonius and Thestylus, display distributions that are congruent with vicariance events associated with the break up of Gondwana. Considering present distribution patterns and phylogeny, the family Bothriuridae is at least 130 million years old. Three historical biogeographical events were important in the evolution of its genera: (1) the break up of Gondwanaland (first Africa, secondarily Australia and South America); (2) development of the high Andes; (3) formation of the arid and semi-arid lands in central-south South America. The most speciose bothriurid genera (e.g. Bothriurus, Brachistosternus) evidently radiated in association with the aridification of southern South America.