Cleft lip and palate associated with other malformations in a neotropical primate (Saimiri ustus).

Cleft lip (with or without cleft palate) has been documented in several species of nonhuman primates, which in general are susceptible at similar doses and stages of gestation to the same teratogens as humans. Cleft lip can be unilateral or bilateral, isolated, syndromic, familial, or genetic. Here we report the first case of syndromic cleft lip and palate in a male bare-eared squirrel monkey (Saimiri ustus).

Variation in clitoral length in rhesus macaques (Macaca mulatta).

Clitoromegaly in the neonatal period is an important morphologic sign that can be useful for sexual determination in aberrant cases. In rhesus monkeys, differentiation of the external genitalia occurs early during gestation (at 55 to 60 d) and is complete by approximately 80 d. Most of the critical steps in genital differentiation in primates occur prenatally.