Alisphenoid strut
Encyclopedia
In some rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, the alisphenoid strut is an extension of the alisphenoid bone that separates two foramina
Foramen
In anatomy, a foramen is any opening. Foramina inside the body of humans and other animals typically allow muscles, nerves, arteries, veins, or other structures to connect one part of the body with another.-Skull:...

 in the skull, the masticatory–buccinator foramen and the foramen ovale accessorius. The presence or absence of this strut is variable between species, but also within them; some Oryzomyini
Oryzomyini
Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of family Cricetidae. It includes about 120 species in about thirty genera, distributed from the eastern United States to the southernmost parts of South America, including many offshore islands...

even have a strut on one side of the skull but lack it on the other side.

Literature cited

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