title: The making of platyrrhine semifolivores: models for the evolution of folivory in primates.
abstract: Among living New World monkeys, Howlers and Muriquis are by far the most folivorous. We examine how well the morphology and behavior of Alouatta and Brachyteles conform to leaf-eating adaptational models derived from other studies. Both genera match these expectations unevenly, which suggests a broader conception of primate folivory is in order. Hence the notion of "semifolivory." While their dentitions prove highly sensitive to selection for leaf-eating, core features relating to body size, brain size, ranging behavior and presumed energy budgets are less predictable corollaries. Leaf-eating in atelines and colobines may have evolved from a preadaptive reliance on seed-eating, which would have necessitated comparable gastric adaptations. Fossils suggest semifolivory in the low-energy Howler lineage may have begun with an increase in body size, a relatively small brain and, possibly, a concomitantly enlarged gut, followed by dental adaptations. It may have advanced via body-size reduction, part of a pioneering adaptation in marginal ecologies on the periphery of rich Amazonian habitats or as a strategy to minimize competition among an abundance of frugivores within the lowland forest-perhaps not as a fallback scheme. In the high-energy Muriqui, semifolivory may have evolved in more intensely seasonal, low-yield forests where frugivores were constrained and rare, a model more consistent with the fallback paradigm. The seed-to-leaves evolutionary pathway hypothesized for anthropoid leaf-eaters may be a widespread phenomenon in primates. We propose it is ultimately rooted in a pre-euprimate reliance on the seeds and seed coats of primitive angiosperms before the latter evolved attractive sugary fruits to coax primates into becoming dispersers of seeds, instead consumers.
authors: Department of Anthropology and Archaeology, Brooklyn College, CUNY, Brooklyn, New York, USA. alfredr@brooklyn.cuny.edu
authors: Alfred L
authors: AL
authors: Rosenberger
authors: Lauren
authors: L
authors: Halenar
authors: Siobhán B
authors: SB
authors: Cooke
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002427:Cebidae / Q000502:physiology*; D004435:Eating / Q000502:physiology; D060434:Herbivory / Q000502:physiology*; D018515:Plant Leaves