摘要：The mandibular fragments from Lothagam (KNM-LT 329) and Tabarin (KNM-TH 13150) were once considered plausible candidates for status as the earliest hominin (e.g., Kramer 1986; Ward and Hill 1987). Recent fieldwork, though, has lessened the relevance of these fossils by recovering samples from horizons more than two million years earlier. Yet despite the increase of comparative samples, these two mandibular fragments remain difficult to diagnose. Here we consider the morphology and dental metrics of these two specimens in comparison to the larger samples of Miocene and early Pliocene hominins recovered during the last fifteen years. We show, based on molar size, that KNM-TH 13150 is consistent with the hypodigm of Ardipithecus, while the Lothagam mandible is not consistent with Ardipithecus in its molar dimensions. These results have important biogeographic implications and hint at a more complex Early Pliocene hominin phylogeny than previously appreciated.
