AGE OF EPIPHYSEAL CLOSURE IN TAMARINS AND MARMOSETS

Estimates of the chronological age for animals of unknown age provide useful information for medical, demographic, and evolutionary studies. Skeletal development, as indicated by epiphyseal closure, can be used to estimate an animal's chronological age or specify its stage of dev elopment. Many studies of Primate skeletal development have used anima ls of unknown age, with the order of epiphyseal closure providing a re lative age for each animal. This study examines the age of epiphyseal closure at 22 epiphyseal sites using animals of known age at death in three calitrichid species (Saguinus fuscicollis, Saguinus oedipus, and Callithrix jacchus). The observed average age of epiphyseal closure i s similar in these tamarins and marmosets. There is a significant diff erence in rate of development between the species. Regression equation s can predict the age of unknown animals to within 4.8 months for S. f uscicollis, 8.6 months for S. oedipus, and 7.6 months for C. jacchus ( twice the standard error of the estimate). These age estimates allow u s to determine if an animal is relatively mature or immature, but are largely unacceptable for studies in which precise age estimates are ne cessary. The order of epiphyseal closure is similar across 11 monkey s pecies (using additional data from published literature) and supports the suggestion of a general pattern in Primate skeletal development. ( C) 1997 Wiley-Liss, Inc.