Dental anomalies in Tolypeutes matacus (Desmarest, 1804) (Mammalia, Xenarthra, Cingulata)

GONZALEZ RUIZ, L. R.; MACPHEE, R.D.

Esquel

Jornada; XXVII Jornadas Argentinas de Mastozoología; 2014

Dental anomalies (e.g., supernumerary or missing teeth) in Dasypodidae have never been thoroughly examined. For this contribution we searched for anomalies in 32 specimens of the three-banded armadillo Tolypeutes matacus from Bolivia, Brazil, Argentina and Paraguay and housed in the Field Museum of Natural History (FMNH) (n=20), National Museum of Natural History (Smithsonian Institution) (USNM) (n=4) and Department of Mammalogy (American Museum of Natural History) (AMNH) (n=8). The typical dental formula of T. matacus consists of 9 upper molariforms (Mf) in the maxilla (mx) and 9 lower molariforms (mf) in the mandible (md). Three categories of dental anomalies were recognized: 1) Presence of premaxillary teeth: FMNH 28345 has a rudimentary teeth in each premaxilla; 2) Presence of supernumerary molariforms (sMf/smf): FMNH 104816 has a sMf between Mf2 and Mf3 in the right mx, and USNM 291935 has a smf between mf3 and mf4 in both md; and 3) Missing molariforms: FMNH 21407 has 8 Mf in its left mx due to the absence of Mf9 and its alveolus. Four specimens from the Park Zoological Gardens have evidence of periodontal disease (FMNH 122233, FMNH 121540, FMNH 186922, FMNH 124570) manifested by the abnormal growth of Mf and mf, loss of molariforms, and malformed alveoli and adjacent bone regions. The presence of premaxillary teeth in extant Dasypodidae is mostly restricted exclusively to Euphractinae (Chaetophractus Fitzinger and Euphractus Wagler), but is occasionally seen in Zaedyus Ameghino (Euphractinae) and Tolypeutes Illiger (Tolypeutini) (this work). If we consider that number and presence of molariforms and premaxillary teeth are variable within both extant and extinct Dasypodidae, the study of exceptional cases may provide evidence for the polarity of these characters and the evolution of dental formulas within Dasypodidae.