Phylogenetic topology and timing of New Zealand olive shells are consistent with punctuated equilibrium
Abstract
The olive shells of the genus Amalda comprises readily recognized species of marine neogastropod mollusks found around the world. The New Zealand Amalda fauna has particular notoriety as providing one of the best demonstrations of evolutionary morphological stasis, a prerequisite for punctuated equilibrium theory. An excellent fossil record includes representation of three extant endemic Amalda species used to explore patterns of form change. However, the phylogenetic relationship of the New Zealand Amalda species and the timing of their lineage splitting have not been studied, even though these would provide valuable evidence to test predictions of punctuated equilibrium. Here, we use entire mitogenome and long nuclear rRNA gene cassette data from 11 Amalda species, selected from New Zealand and around the world in light of high rates of endemicity among extant and fossil Amalda. Our inferred phylogenies do not refute the hypothesis that New Zealand Amalda are a natural monophyletic group and therefore an appropriate example of morphological stasis. Furthermore, estimates of the timing of cladogenesis from the molecular data for the New Zealand group are compatible with the fossil record for extant species and consistent with expectations of punctuated equilibrium.
Gemmell, M.R.; Trewick, S.A.; Hills, S.F.K.; Morgan-Richards, M. (2020). Phylogenetic topology and timing of New Zealand olive shells are consistent with punctuated equilibrium. J. Zoo. Syst. Evol. Research 58(1): 209-220. https://dx.doi.org/10.1111/jzs.12342