Boyer diss 2009 1046..

were acquired. Specifically, the “angiosperm exploitation hypothesis” of R. Sussman
(Sussman and Raven, 1978; Sussman, 1991) argues that features reflecting the ability to
locomote in trees (like relatively long fingers and toes, and a divergent, opposable hallux
with a nail) originally facilitated access to angiosperm resources (flowers, nectar, pollen,
fruits, seeds, etc.) in a fine branch niche, making grasping features of primary
importance. Sussman believed that teeth should and do show increasing specialization
towards frugivory through early primate evolution, as elegantly argued by Szalay (1968).
Visual system features are predicted to appear at the same time as or after grasping
features, but there is no specific point in primate-euprimate evolution when visual system
features are seen as integral or critical in Sussman’s hypothesis. Instead, the visual
system features are thought to be further improvements for a life spent in the trees
searching out angiosperm products, and are described as an eventual consequence of
coevolution between angiosperms, primates and other vertebrates that utilize angiosperm
resources in an arboreal milieu (e.g., bats and various birds). The view of early primateeuprimate
evolution presented by phylogenetic hypotheses that are supported by recent
cladistic analyses corroborates the angiosperm exploitation hypothesis (Bloch et al.
2007), but refutes the “visual predation hypothesis” of Cartmill (1972). The visual
predation hypothesis suggests that the synchronized evolution of euprimate pedal
grasping and visual features allowed euprimates to visually locate and manually
apprehend insects in the shrub-layer of forests at night. Decoupled evolution of grasping
and visual features, and the precedence of grasping features in the course of evolution
leading up to euprimates, is inconsistent with this hypothesis.
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