Abstract

ABDALA, F.; MOCKE, H.  and  HANCOX, P.J.. Lower Triassic postcanine teeth with allotherian-like crowns. S. Afr. j. sci. [online]. 2007, vol.103, n.5-6, pp.245-247. ISSN 1996-7489.

The Allotheria are fossil mammals with upper and lower post-canines usually showing two longitudinal rows of cusps separated by a central valley. The group comprises the poorly known haramiyids, mostly represented by isolated teeth, and the notably diverse and long-lived multituberculates; its monophyly is uncertain. The oldest records of this particular group are the Late Triassic (Norian-Rhaetian) haramiyids. We present here postcanines with haramiyid-like crowns that were recovered from the Lower Triassic of South Africa. A distinguishing feature of the new teeth is that they are single-rooted. This is the oldest record of mammal-like teeth with crowns having parallel rows of cusps, representing a temporal extension of some 43 million years from similar crown patterns of haramiyids and tritylodontids. This finding reinforces evidence of the remarkable faunal turnover of therapsids in the Early/Middle Triassic, at which time an explosive origin followed by a rapid early diversification of herbivorous/omnivorous forms with occluding expanded postcanines took place.

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