New paper: reconstructing the history of viviparity in squamate reptiles
Recently published in the Journal of Evolutionary Biology -
Evolutionary origins of viviparity consistent with palaeoclimate and lineage diversification
It has long been argued that the origin of viviparity is related to cold climatic conditions. However this is challenging to disentangle correlation from causation, and response from cause. Also many studies have examined particular species groups but we have lacked the data so far to estimate a time tree in context of climate. Here led by Hans Recknagel in his interdisciplinary PhD studentship, we showed that stable and long-lasting cold climatic conditions are correlated with transitions to viviparity across squamates. Interestingly, this correlation of parity mode and palaeoclimate is mirrored by background diversification rate in squamates. Further, exploring patterns by simulations of a binary trait also showed a similar association with palaeoclimate. Overall this suggests that vivparity evolution cannot be separated from squamate lineage diversification. We suggest that parity mode transitions depend on environmental and intrinsic effects and that background diversification rate may be a factor in trait diversification more generally.
Ultimately we need more genome-informed and mechanistic information about the basis of viviparity to better retrace its evolution, but these data are lacking.
