Although caecilian amphibians (Gymnophiona) are widely recognised as the least studied tetrapod Order, substantial recent progress in understanding their evolutionary relationships makes developing a comprehensive species phylogeny a realistic possibility in the short term. The proposed studentship will address this task by generating additional morphological and molecular data, and integrating these with existing data sets using both standard and supertree phylogenetic inference methods. The resulting tree will then be used to study aspects of the evolution of this previously neglected radiation.
New character data will be developed from the urogenital system and reproductive organs, and for limited nuclear and mitochondrial genes selected for their maximal information content (using likelihood methods) and to efficiently enhance the effective overlap between the existing data sets (using supertree methods). The student will have the opportunity to refine the latter methods, and construction of the caecilian tree will provide the first test case for experimental design using this innovative approach. The tree will be dated and used to investigate patterns of diversification, and compared to the comprehensive trees for frogs and salamanders to complete the picture for the Amphibia. Broad scale work will be complemented by discrete projects on one or more small radiations chosen for their potential to yield insights of a more general nature.
This will include siphonoform caecilians which are of interest because of their parental care and for being one of the few vertebrate species groups showing sufficient multiple mt. gene order rearrangements to enable tests of proposed rearrangement mechanisms. Fieldwork will fill the gaps in current sampling and, based on previous experience, is expected to lead to the discovery and description of new species. The student will receive training in taxonomy, tropical fieldwork, vertebrate morphology, molecular biology, theoretical and practical phylogenetics, bioinformatics, and comparative evolutionary biology. They will benefit from being part of the large and dynamic Herpetology Research Group, and from working at the intersection of two of its core foci, caecilians and supertrees.
Drs. Mark Wilkinson (M.Wilkinson@nhm.ac.uk), David Gower (D.Gower@nhm.ac.uk), Prof. Andy Purvis (Imperial).