Evolutionary morphology, cranial biomechanics and the origins of tarsiers and anthropoids

摘要: During the Time of Messel, dominant groups primates were adapiform strepsirhines and tarsiiform haplorhines, both important in discussions anthropoid origins. Living tarsiers are at centre these ideas as one school thought, representing Tarsier-Anthropoid Hypothesis, holds they sister-group Anthropoidea. The Tarsier-Tarsiiform however, maintains that phyletically nested among (paraphyletic) fossil tarsiiforms (∼omomyids). Orbital morphology is crucial to this debate: possibility postorbital septa anthropoids synapomorphic it evolved their last common ancestor insulate eyeballs from muscular interference. Our biomechanical model forces acting on enormous orbits especially during locomotion provides a strong counterargument proposition. uniquely specialised orbita Tarsius, which include prominent circumorbital flanges continuous with septum, designed sustain inertial loads transmitted by acceleration deceleration phases powerful leaping, for Tarsius also famous. thus secured, pressure absorbed retina minimised, enlarging its surface area contact “walled socket”, i.e., extra-fossa expansion flanges. tarsier septum is, therefore, form–function convergence small-eyed condition. Several related Eocene exhibit precisely Tarsius-like rostrum relating eyeball hypertrophy, although lack exaggerated septal only rarely postcranial features indicative super leaping abilities.