Variation in the strength of allometry drives rates of evolution in primate brain shape - Supplementary Material

<p>Large brains are a defining feature of primates, as is a clear allometric trend</p> <p>between body mass and brain size. However, important questions on the</p> <p>macroevolution of brain shape in primates remain unanswered. Here we</p> <p>address two: (i), does the relationship between the brain size and its shape</p> <p>follow allometric trends and (ii), is this relationship consistent over evolutionary</p> <p>time? We employ three-dimensional geometric morphometrics and</p> <p>phylogenetic comparative methods to answer these questions, based on a</p> <p>large sample representing 151 species and most primate families. We found</p> <p>two distinct trends regarding the relationship between brain shape and</p> <p>brain size. Hominoidea and Cercopithecinae showed significant evolutionary</p> <p>allometry, whereas no allometric trends were discernible for Strepsirrhini,</p> <p>Colobinae or Platyrrhini. Furthermore,we found that in the taxa characterized</p> <p>by significant allometry, brain shape evolution accelerated, whereas for taxa in</p> <p>which such allometrywas absent, the evolution of brain shape decelerated.We</p> <p>conclude that although primates in general are typically described as largebrained,</p> <p>strong allometric effects on brain shape are largely confined to the</p> <p>order's representatives that display more complex behavioural repertoires.</p>