A morphological study on the dentition of Tupaia glis

Abstract

The dentition of Tupaia glis was observed. The materials for this study are 7 dry skulls of common tree shrew.The following results are obtained: 1. The upper molar pattern of the Tupaia glis is the typical dilambdodont type. The paracones of the upper molars are well-developed. And the metacone of the third molar is less developed. 2. Three stylar cusps and two bucal cusps of the first and second molar are well-developed, but metastyle of the third molar is absent. The parastyle and metastyle are also observed in the third and fourth premolars. 3. The protocones of the upper molars and the fourth premolar are well-developed but those of the third premolar is less developed. 4. The hypocone is derived from distolingual elevation of the cingulum. This cusp of the upper first molar is well-developed. 5. The lower molar is composed of a trigonid and talonid. There are three cusps in the trigonid and talonid. The lower fourth and third premolar are also composed of a trigonid and talonid, but there is only one cusp in the talonid. The upper and lower second premolars and the front teeth are haplodont. The lower first and second incisors are procumbent, and form a dental comb.