Extended Data Fig. 6: Early hominin lower premolar morphology.
From: New finds shed light on diet and locomotion in Australopithecus deyiremeda
Relatively unworn lower premolars of Au. afarensis (a), BRT-VP-2/135 (b), Au. anamensis (c), and Ar. ramidus (d). Some P3s of Au. afarensis have more primitive occlusal morphology (e.g., metaconid non-existent or incipient, centrally positioned protoconid (white arrow)). However, like the derived P3s with well-developed metaconid, they are associated with a P4 that has a rhomboidal occlusal outline. The mesial protoconid crest-transverse crest angle is <90° as shown in A.L. 128-23 and A.L. 288-1i. On the other hand, The P3s of BRT-VP-2/135 (b), have diminutive to absent metaconid with a centrally positioned protoconid and the mesial protoconid crest-transverse crest angle is >90°. The P4s are also oval in occlusal outline. This is the combination of traits seen in the earlier hominins such as Au. anamensis (c) and Ar. ramidus (d).
