The basicranial region of marsupicarnivores (Marsupialia), interrelationships of carnivorous marsupials, and affinities of the insectivorous marsupial peramelids

Abstract

The basicranial region is examined in detail in didelphids, dasyurids, thylacinids, borhyaenids, myrmecobiids, and comparisons are made with notoryctids and peramelids. Three dasyurid genera (Sminthopsis, Antechinus and Planigale) were doubly injected with latex and basicranial foramina identified partly on the basis of the vessels which they transmit. The resulting terminology differs in several significant ways from terminologies currently in use. A basic terminology for sinuses, recesses, foramina and other structures in the basicranial region is developed from this new information combined with existing systems used for eutherian mammals and mammal-like reptiles. It is concluded that on the basis of basicranial structure didelphids are structurally ancestral to all other marsupicarnivores, directly or indirectly. They are directly ancestral to thylacinids, borhyaenids, dasyurids and peramelids. Myrmecobiids are structural descendents of dasyurids. Notoryctids are not marsupicarnivores and may be diprotodonts. No special relationships exist between thylacinids and dasyurids or between dasyurids and peramelids. All groups except didelphids show unique specializations in some members and several show evidence of convergence in sinus development and structure of the foramen ovale.