Postorbital bar
The postorbital bar is where the zygomatic bone and the frontal bones join to form a lateral strut which runs around the eye socket of most strepsirrhine primates[1] and some other mammals, such as the hyrax. This is in contrast to the haplorhine primates, which have evolved fully enclosed sockets.[1]
One theory for this evolutionary difference is the relative importance of vision to both orders. As haplorrhines (tarsiers and simians) tend to be diurnal, and rely heavily on visual input, many strepsirrhines are nocturnal and have a decreased reliance on visual input.[1]
References
This article is issued from Wikipedia - version of the 3/17/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.