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). Associated with the orofacial clefts, the monkey manifested absence of bones, malformation of vertebrae L3, only 4 fingers in each hand, and shortening of tendons leading to inflection of the hands and fingers. Previous reports describing cleft lip and palate in other squirrel monkeys (Saimiri sciureus) in other breeding units have suggested consanguineous mating as a possible cause. Although the etiology in the case we present is unknown, we discuss factors associated with orofacial clefts in humans and various nonhuman primates.

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. We sought to determine clitoral size in normal rhesus monkeys (Macaca mulatta) and possible effects of age and inheritance. Clitoral length was highly variable and had no relationship to fertility. Statistical evaluation revealed no association in the distribution of daughters with and without clitoris between mothers with and without clitoris. However, even when mated with several female monkeys, some male macaques produced primarily daughters without clitoris.