Dear colleagues – I’d like to announce a new paper just accepted for publication and now online at:
Here is the citation and abstract:
Montgomery, SH, Geisler, JH, McGowen, MR, Fox, C, Marino, L and Gatesy, J. (accepted) The evolutionary history of cetacean brain and body size. Evolution. DOI: 10.1111/evo.12197
Abstract
Cetaceans rival primates in brain size relative to body size and include species with the largest brains and biggest bodies to have ever evolved. Cetaceans are remarkably diverse, varying in both phenotypes by several orders of magnitude, with notable differences between the two extant sub-orders, Mysticeti and Odontoceti. We analyzed the evolutionary history of brain and body mass, and relative brain size measured by the encephalization quotient (EQ), using a dataset of extinct and extant taxa to capture temporal variation in the mode and direction of evolution. Our results suggest that cetacean brain and body mass evolved under strong directional trends to increase through time, but decreases in EQ were widespread. Mysticetes have significantly lower EQs than odontocetes due to a shift in brain:body allometry following the divergence of the suborders, caused by rapid increases in body mass in Mysticeti and a period of body mass reduction in Odontoceti. The pattern in Cetacea contrasts with that in Primates, which experienced strong trends to increase brain mass and relative brain size, but not body mass. We discuss what these analyses reveal about the convergent evolution of large brains, and highlight that until recently the most encephalized mammals were odontocetes, not primates.
Stephen Montgomery (stephen.montgomery@cantab.net) is the corresponding author.
Thanks very much.
Lori Marino
Lori Marino, PhD
Senior Lecturer
The Graduate Institute of Liberal Arts
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Emory University
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