Abstract
The following five apomorphies are found in Callitrichidae.
1. The anterior lower teeth show short-tusked condition.
2. On first upper molar, the disto-lingual cusp (hypocone) is reduced.
3. On first upper molar, the lingual cingulm is reduced.
4. Third molars are absent.
5. Septa connect the promontory of tympanic cavity with the inner surface of auditory bulla.
The phylogeny of Callitrichidae is reconstructed as follows based on the synapomorphies. At first, Callimico were differentiated, followed by Saguinus, then Leontopithecus, and finally Callithrix and Cebuella were differentiated each other.
