Primer registro de un diente supernumerario en Glyptodontidae (Mammalia, Xenarthra)

MARTIN, G.; GONZALEZ-RUIZ, L.; CIANCIO, M.R; ZURITA, A. E

Mar del Plata

Jornada; XXVI Jornada Argentinas de Mastozoología; 2013

SAREM

The presence of extra teeth, defined as the presence of teeth in excess of the normal expected number in any of the dental arcades, has been reported for nearly all orders of recent mammals (among others, Wolsan, 1984; Colyer, 1990; Dixon et al., 2005; Natsume et al., 2005; Martin, 2007; Zinoviev, 2010) but are rarely recorded for fossil mammals (Wilson, 1955; McKenna, 1960; Fine, 1964; Wang and Wu, 1976; Rose and Smith, 1979; Fordyce, 1982; Arnal and Vucetich, 2011). These extra teeth occur in both sexes, in wild and captive individuals, in all tooth classes and both teeth generations, in both upper and lower series, both bilaterally and unilaterally, and in the right or left side. They are situated either within a tooth row, as peripheral or intercalate teeth, or outside it, internally or externally (Wolsan, 1984). These teeth are categorized as: (1) supplemental teeth which resemble teeth of the normal series in both crown and root morphology though not always in size; (2) haplodont supernumerary teeth with simple, usually conical, crowns and single roots; and (3) tuberculate extra teeth with complex crowns that have what can be called an occlusal surface bearing several tubercles (Colyer, 1990). Several explanations have been proposed to account for the occurrence of extra teeth in mammals: (1) persistence of deciduous teeth; (2) excessive development in skull size; (3) return to a lost primitive condition (= atavism); (4) mutation producing new tooth germ; and (5) a complete splitting and development of a tooth germ (Wood and Wood, 1933; Wolsan, 1984; Colyer, 1990; De Moraes et al., 2001).