In rodents, sphenopalatine vacuities are perforations of the roof of the mesopterygoid fossa, the open space behind the palate, in between the parapterygoid fossae.[1] They may perforate the presphenoid or basisphenoid bone.[2] Their development and form are variable between and within species, and features of the sphenopalatine vacuities have been used as characters in cladistic analyses.[3]
Among Oryzomyini, a mainly South American group, a 2006 study distinguished three character states—large, wide vacuities, as among others in Oligoryzomys and Holochilus; small, narrow vacuities, as among others in Lundomys and Nephelomys; and no or vestigial vacuities, as among others in Mindomys and Oryzomys.[2] Phyllotini all have very large sphenopalatine vacuities, as does Sigmodon. The vacuities in Reithrodon, formerly considered a phyllotine, are especially large.[4] Nyctomys is special in having sphenopalatine vacuities restricted to the basisphenoid bone.[2] Character polarity for the development of the vacuities in Cricetidae is difficult to determine, but their absence may be primitive in the Neotominae.[4]
The development of sphenopalatine vacuities has also been used to distinguish among members of the Sciurini group of squirrels.[5]
References edit
Literature cited edit
- Carleton, M.D. 1980. Phylogenetic relationships in neotomine-peromyscine rodents (Muroidea) and a reappraisal of the dichotomy within New World Cricetinae. Miscellaneous Publications, Museum of Zoology, University of Michigan 157:i–vii+1–146.
- Moore, J.C. 1959. Relationships among the living squirrels of the Sciurinae. Bulletin of the American Museum of Natural History 118:157–206.
- Steppan, S.J. 1995. Revision of the tribe Phyllotini (Rodentia: Sigmodontinae), with a phylogenetic hypothesis for the Sigmodontinae. Fieldiana Zoology 80:1–112.
- Weksler, M. 2006. Phylogenetic relationships of oryzomyine rodents (Muroidea: Sigmodontinae): separate and combined analyses of morphological and molecular data. Bulletin of the American Museum of Natural History 296:1–149.