Fig. 77 in The Mammals Of Paracou, French Guiana: A Neotropical Lowland Rainforest Fauna Part 2. Nonvolant Species

Fig. 77. Morphology of the incisive foramina and the posterior palate in Proechimys guyannensis (A, AMNH 266595) and P. cuvieri (B, AMNH 266592). Whereas the bony septum that separates the right and left incisive foramina is usually incomplete in P. guyannensis, the septum is always complete in P. cuvieri. Additionally, the incisive foramina of P. cuvieri are usually constricted posteriorly by well­developed lateral flanges of the maxillary bone, the posterior palate often has a prominent median keel, and the mesopterygoid fossa is typically broad and shallow. By contrast, the bony relief of the posterior palate is less prominent in most specimens of P. guyannensis, in which the mesopterygoid fossa is often narrower, more acutely angled, and penetrates farther between the toothrows. Scale bar = 5 mm.