Capsular process

The marsh rice rat (Oryzomys palustris) has a reduced capsular process.^[1]

In rodents, the capsular process or projection is a bony capsule that contains the root of the lower incisor. It is visible on the labial (outer) side of the mandible (lower jaw) as a raising in the bone.^[2] There is marked variation within species in the development of this process.^[3]

Most oryzomyines have a well-developed capsular process, which is usually located behind the coronoid process, but many have a small one, usually located below the coronoid process, and some lack the structure entirely.^[4] Phyllotines and akodontines are also variable in their development of a capsular process.^[5]

References

1. Weksler, 2006, p. 42
2. Weksler, 2006, p. 41
3. Steppan, 1995, p. 26
4. Weksler, 2006, pp. 41–42
5. Steppan, 1995, table 4, char. 33

Literature cited

• 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.