Ambondro mahabo jaw
The jaw of Ambondro mahabo, seen in lingual view (from the side of the tongue). The scale bar is 1 mm (0.039 in) long. This mammal species is known only from this fragmentary lower jaw with three teeth, interpreted as the last premolar and the first two molars. It is the oldest known mammal with putatively tribosphenic teeth.Photo: André R. Wyss