Rak Yoel, Ginzburg Avishag, Geffen Eli
Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
Proc Natl Acad Sci U S A. 2007 Apr 17;104(16):6568-72. doi: 10.1073/pnas.0606454104. Epub 2007 Apr 10.
Mandibular ramus morphology on a recently discovered specimen of Australopithecus afarensis closely matches that of gorillas. This finding was unexpected given that chimpanzees are the closest living relatives of humans. Because modern humans, chimpanzees, orangutans, and many other primates share a ramal morphology that differs from that of gorillas, the gorilla anatomy must represent a unique condition, and its appearance in fossil hominins must represent an independently derived morphology. This particular morphology appears also in Australopithecus robustus. The presence of the morphology in both the latter and Au. afarensis and its absence in modern humans cast doubt on the role of Au. afarensis as a modern human ancestor. The ramal anatomy of the earlier Ardipithecus ramidus is virtually that of a chimpanzee, corroborating the proposed phylogenetic scenario.
在最近发现的阿法南方古猿标本上，下颌支形态与大猩猩的下颌支形态极为相似。考虑到黑猩猩是现存与人类亲缘关系最近的物种，这一发现出人意料。由于现代人类、黑猩猩、猩猩以及许多其他灵长类动物都具有与大猩猩不同的下颌支形态，所以大猩猩的解剖结构必定代表着一种独特的情况，而这种形态在化石人族中的出现必定代表着一种独立衍生出来的形态。这种特殊形态在粗壮南方古猿中也有出现。后一种古猿和阿法南方古猿都具有这种形态，而现代人类却没有，这让人质疑阿法南方古猿作为现代人类祖先的角色。早期的拉密达地猿的下颌支解剖结构实际上与黑猩猩的相似，这证实了所提出的系统发育情况。
