RT Journal Article
SR Electronic
T1 Maternal investment evolves with larger body size and higher diversification rate in sharks and rays
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.01.05.475057
DO 10.1101/2022.01.05.475057
A1 Christopher G Mull
A1 Matthew W Pennell
A1 Kara E Yopak
A1 Nicholas K Dulvy
YR 2022
UL http://biorxiv.org/content/early/2022/01/06/2022.01.05.475057.abstract
AB Across vertebrates, live-bearing has evolved at least 150 times from the ancestral state of egg-laying into a diverse array of forms and degrees of prepartum maternal investment. A key question is how this diversity of reproductive modes arose and whether reproductive diversification underlies species diversification? To test these questions, we evaluate the most basal jawed vertebrates, Chondrichthyans, which have one of the greatest ranges of reproductive and ecological diversity among vertebrates. We reconstructed the sequence of reproductive mode evolution across a time-calibrated molecular phylogeny of 610 chondrichthyans. We find that egg-laying is ancestral, and that live-bearing evolved at least seven times. Matrotrophy (i.e. additional maternal contributions) evolved at least 15 times, with evidence of one reversal. In sharks, transitions to live-bearing and matrotrophy are more prevalent in larger-bodied species in the tropics. Further, the evolution of live-bearing is associated with a near-doubling of the diversification rate, but, there is only a small increase in diversification associated with the appearance of matrotrophy. The chondrichthyan diversification and radiation, particularly throughout the shallow tropical shelf seas and oceanic pelagic habitats, appears to be associated with the evolution of live-bearing and the proliferation of a wide range of maternal investment in their developing offspring.Competing Interest StatementThe authors have declared no competing interest.