Diversification and diets on tropical seashores

Phylogenetic analysis and fossil record of the rapanine murex snails (Gastropoda: Rapaninae)

The tempo, mode and geography of diversification in the marine tropics are subjects of intense current debate.

Crucial questions include the role of long-term climate change, recent glaciations, ancient tectonics and ecological specialization in the speciation process. The ‘marine speciation paradox’ is still far from understood: if speciation is allopatric, how is isolation achieved in the face of wide dispersal of planktonic larvae? Have temperate zones been colonized from the tropics or vice versa? Does loss of planktotrophic larvae restrict clades to cold water?

Shallow-water molluscs provide excellent models for evolutionary questions: they are accessible, taxonomically and ecologically well known, and often have good fossil records. Nevertheless, a robust phylogenetic framework is lacking for most groups. The Muricidae are the largest and most ecologically diverse family of predominantly intertidal carnivorous snails. The aim of the PhD project is to develop a molecular phylogeny as a key to the evolutionary radiation of this major group of mainly tropical molluscs.

Objectives

• Using a genus-level phylogeny of the available range of the entire family, we aim to test the widespread belief that the tropics have been a source of diversity for temperate regions.
• Using a phylogeny of all available genera in the subfamily Rapaninae, we will examine the role of dietary specialisation in this adaptive radiation.
• At the level of species, we will identify geographic modes and timing of speciation events in the Indo-Pacific clade of 'thaid' rapanines.

Outcomes for the student

The student will receive training in molecular laboratory techniques, phylogenetic analysis, bioinformatics, anatomical dissection, morphological examination of fossils, tropical fieldwork and communication of their results to both scientific and public audiences.

Supervisors

Dr Suzanne Williams and Dr David Reid (Zoology, NHM); Dr Timothy Barraclough (Imperial College).

Contact for further information: Dr John Taylor (j.taylor@nhm.ac.uk , Zoology, NHM).