Michael Gemmell

Doctor of Philosophy
Study Completed: 2017
College of Sciences


Thesis Title
Genetic and Phenotypic Lineages in Neogastropod Molluscs: A Journey Through Time and Morphospace

Read article at Massey Research Online: MRO icon

Some marine snails living in New Zealand have an excellent fossil record providing the means to test evolutionary theory. Mr Gemmell used a combination of genetic and shape analysis to first test if species really were separate lineages. He looked at rocky-shore whelks (Buccinulum) and sea snails, the olive shells (Amalda), and found that some species were separate genetic lineages and some species were actually part of the same lineage. In the olive shells, relationships between species, shape, and genetic lineages all showed the same pattern. Using fossil olive shells, the evolution of shape through millions of years was analysed to establish how well it conformed to a punctuated equilibrium model, a theory of how species evolve. Some (but not all) of the shape traits examined evolved in a way consistent with punctuated equilibrium.

Professor Mary Morgan-Richards
Dr James Crampton
Professor Steven Trewick
Dr Simon Hills