Towards an all-species phylogeny of the scorpion family Bothriuridae

MATTONI, C.I., J. OCHOA, A. A. OJANGUREN-AFFILASTRO & L. PRENDINI

San Miguel de Tucumán, Argentina

Congreso; XXVII Hennig Meeting and VII Reunión Argentina de Cladística y Biogeografía; 2008

The scorpion family Bothriuridae comprises 127 described species in 13 genera, with a Gondwana distribution in South America, southern Africa and Australia. Phylogenetic relationships among the bothriurid genera were previously studied, but lacked resolution for internal nodes. Recent fieldwork provided sufficient samples to obtain DNA sequences from most species in the family, for combination with new and existing morphological characters. The goals of the study were to (1) test the monophyly of Bothriuridae and determine its phylogenetic position with respect to other scorpion families; (2) resolve the phylogenetic relationships among and test the monophyly of the bothriurid genera; (3) evaluate the effect of increased taxon sampling on phylogenetic relationships in the family. The dataset comprised 141 bothriurid terminals (80% of the described species plus 36 undescribed species, including a new genus) and 16 outgroups. A comprehensive revision of external morphology and internal anatomy was undertaken, resulting in more than 250 characters, to which DNA sequences from five loci (ca. 4.2 kb) were added after aligning with Mafft and Prank+f. Phylogenetic analyses, under equal and implied weights, were conducted and support for each group calculated using TNT. The addition of DNA sequences slightly changed results of the separate morphological analysis, increasing support for most internal branches. A denser taxon sample increased the clades’ stability and yielded stronger support for most branches. The monophyly of Bothriuridae was supported, but its placement as sister group of the Scorpionoidea s. str. remains uncertain. The validity of Brandbergia (recently synonymized) was confirmed based on morphology; it was placed sister to other bothriurid genera, and must be reinstated. The monophyly of Brachistosternus and its current division into three subgenera were confirmed, and its position as the sister group of other bothriurids (excepting Brandbergia, Lisposoma and Thestylus) was established. Bothriurus and Orobothriurus were polyphyletic: three new genera must be created. Brazilobothrius is placed deeply inside the bonariensis clade of Bothriurus and must be synonymized. Vachonia and Timogenes grouped as sister taxa, in a monophyletic group with the inermis clade of Bothriurus. Tehuankea was closely related to Centromachetes and (Cercophonius + Urophonius). The position of Phoniocercus is unstable: it groups with Tehuankea and related genera or with (Pachakutej (“Bothriurus” (Vachonia + Timogenes))). Genera presenting the most plesiomorphic characters, Brandbergia, Lisposoma, and Thestylus, display distributions congruent with vicariance events associated with the breakup of Gondwana.