New Dental Anomalies in the Greater Japanese Shrew Mole Urotrichus talpoides (Eulipotyphla: Talpidae)

Abstract

Dental anomalies in the greater Japanese shrew mole Urotrichus talpoides Temminck, 1841 (Eulipotyphla: Talpidae) were examined, based on 1001 specimens. We followed the dental formula of U. talpoides I 2/1, C 1/1, P 4/3, M 3/3 = 36, which is adopted by the most recent Japanese researchers, and found dental anomalies in 17 specimens involving 12 instances of absent tooth, four of extra tooth, and one of connate tooth. Of these, the following dental anomalies are reported in U. talpoides for the first time: extra tooth posterior to the upper canine (C1), extra tooth posterior to the upper second premolar (P2), extra teeth on the inner sides of the upper fourth premolars (P4), and connate tooth on the lower canine (C1). The most frequently observed dental anomaly was the absent tooth on C1 (52.9%), whereas the others were not common (< 11.8%). Our results indicate that dental anomalies in U. talpoides in Urotrichini possess the different pattern from those in species in Scalopini and Talpini. On the other hand, alternative hypothesis of dental formula I 3/2, C 1/1, P 3/2, M 3/3 = 36 explains the observed anomaly pattern in line with the general trend of dental anomalies in Talpini and Scalopini.