Developmental pattern of the bony tentorium of spider monkeys (Ateles)

Based on their developmental patterns, the bony tentorium (BT) and bony falx (BF) of mammals can be classified into two types, the carnivoran type and the dolphin type. The former develops as part of the skull bones during the fetal period and is already completed at birth, while the latter is gradually formed by ossification in the tentorium cerebelli (TC) and falx cerebri (FC) during the course of aging. The BT of spider monkeys is assigned to the dolphin type.