Prosimian Morphology

From Primatome

"Prosimians," the common name for the suborder Prosimii, means "before apes." Prosimians are said to be more "primitive" than other primates, because some of their anatomical characteristics are found in some other mammals but not in anthropoid primates. For instance, the tapetum (found in all prosimians except tarsiers) is a layer in the retina of the eye that reflects light and enhances night vision. It is found in cats and other nocturnal mammals whose eyes shine in the dark when a flashlight is pointed in their direction.  Prosimians also have a moist rhinarium(also found in dogs), a structrue of the nose that enhances the perception of smell. Prosimians are active at night and communicate by marking territories with their special scent glands.

Some aspects of prosimian reproductive anatomy differ from those of anthropoid primates. For example, prosimians have a different-shaped uterus(bicornuate) and a different type of placenta(epitheliochorial). Many prosimians have at least four nipples and produce litters rather than a single infant.

Additionally, the skulls of prosimians have smaller brain cases than those of higher primates and do not have closed eye sockets. The two halves of the lower jaw of prosimians are mobile, not fused together as in anthropoids.

-from The Pictorial Guide to the Living Primates by Noel Rowe