title: The orbital mosaic in prosimians and the use of variable traits in systematics.
abstract: Study of 579 skulls, representing all 33 extant prosimian species and several anthropoids, shows that an orbital exposure of the ethmoid occurs in most Malagasy genera. A palatine-lacrimal contact is normal only in Lemur; the zygomatic-lacrimal contact occurs in most lorisiform species. Lepilemur shows possibly significant resemblances to lorisiforms. The vomer appears in the orbit of some ceboids. Cebids are distinguished by a canal running from the orbital apex through the basicranium. It is argued that skull shape and jaw musculature affect the size and shape of certain orbital-mosaic components. Frequencies of traits, rather than typologically 'normal' traits, may be taken as synpomorphies linking different species cladistically.
mesh_terms: D000818:Animals; D009915:Orbit / Q000033:anatomy & histology*; D013100:Sphenoid Bone / Q000033:anatomy & histology; D011443:Strepsirhini / Q000033:anatomy & histology / Q000145:classification*; D015050:Zygoma / Q000033:anatomy & histology