In some
rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...
s, the alisphenoid strut is an extension of the
alisphenoid bone that separates two
in the skull, the
masticatory–buccinator foramen and the
. The presence or absence of this strut is variable between species, but also within them; some
Oryzomyini
Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of ...
even have a strut on one side of the skull but lack it on the other side.
[Weksler, 2006, p. 38]
References
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Literature cited
*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.
Rodent anatomy