| Recent study of new material of the trematochampsid crocodyliform Trematochampsa oblita, from the Late Cretaceous of Madagascar, has provided additional data for a cladistic analysis of the Family Trematochampsidae, an enigmatic group of metasuchian crocodyliforms known from the Cretaceous of Gondwana and the Tertiary of Europe. Among the questions addressed were: (1) Is the Family Trematochampsidae monophyletic? (2) How do trematochampsids relate to other crocodilian groups that have been hypothesized to be closely related, notably peirosaurids? (3) Is the genus Trematochampsa monophyletic with respect to other trematochampsids? and (4) What are the implications for biogeography?; For the cladistic analysis, PAUP*4.0 was employed, using a variety of search algorithms on a data matrix that included thirty unordered characters and thirteen total taxa, including two outgroups (Araripesuchus patagonicus and Notosuchus terrestris), two peirosaurids ( Peirosaurus tormini and Lomasuchus palpebrosus), and the nine named trematochampsid species. Strict and Adams consensus trees were obtained with the data, one set including and another excluding the two peirosaurids. A monophyletic Trematochampsidae was recovered in both options, and the peirosaurids, when included, fall within Trematochampsidae. The genus Trematochampsa itself, however, was found to be paraphyletic, with Trematochampsa oblita closer to the European taxa on the consensus tree that does not include the peirosaurids. The two European Tertiary taxa, Bergisuchus dietrichbergi and Iberosuchus macrodon, were found to be sister taxa and to occupy a relatively crownward position in the clade.; The results of the analysis support the use of a vicariance biogeography model to explain the distribution of Gondwanan trematochampsids. However, a dispersal model best explains the presence of the Tertiary forms in Europe. |
