image: What is "early Homo"? (A to C, F, G, H) Specimens attributed to Homo with dental and mandibular features that resemble those of australopiths [e.g., posteriorly narrow/tapered molars; notch between cheek-facing/buccal cusps (*); anteriorly tall mandible], and (D, E, G) australopiths with features claimed to be specific to Homo [e.g., anteriorly narrow molars; no buccal-cusp notch; last molar not entirely masked by the ascending portion of the mandible (arrow)]. A: OH7 (Homo habilis); B: KNM-ER 992 (H. ergaster); C: Sangiran 6 (H. erectus); D and G: Omo 75-1969-14A (australopith, Paranthropus aethiopicus), (D) occlusal, (G) lateral; E: A.L.128-23 (Australopithecus afarensis); F: Tighenif 1 (H. erectus); H: Tabun II (H. neanderthalensis). The OH7, KNM-ER 992, Sangiran 6, and Tighenif 1 molars narrow posteriorly (A, B, C, and F), but in Omo 75-1969-14A and A.L.128-23 they are narrower anteriorly (D and E). A buccal notch (*) is present in KNM-ER 992 (B), Sangiran 6 (C), and Tighenif (F), but not in Omo 75-1969-14A (D) and A.L.128-23 (E). The last molar of Omo 75-1969-14A (G) would have been partially exposed in front of the ramus (arrow). The Tabun II mandible (H) is tall anteriorly. The fossils are not to scale. This material relates to a paper that appeared in the Aug. 28, 2015, issue of Science, published by AAAS. The paper, by J.H. Schwartz at University of Pittsburgh in Pittsburgh, Pa., and colleagues was titled, "Defining the genus Homo." view more
Credit: Jeffrey H. Schwartz