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- RE:
Did A. afarensis herald the rise of long childhoods in hominids, as Gunz et al. suggests?
This is unlikely, since Gunz et al. showed that the endocast of afarensis had an apelike brain organization.
Equally likely, A. afarensis might simply have heralded the rise of longer childhoods in gorillas: gorillas mature more slowly than chimps do.
In fact, most East-African australopithecine fossils (afarensis, aethiopicus, boisei) have a lot of gorilla-like features, and the more recent fossils (aethiopicus-boisei) seem to have even more gorilla features than the earlier ones (afarensis), e.g.
- Ryan & Johanson 1989: "Incisal dental microwear in A. afarensis is most similar to that observed in Gorilla".
- Johanson & Edey 1981:351: The composite skull reconstructed mostly from A.L.333 specimens "looked very much like a small female gorilla".
- Walker cs 1986: "Other primitive features found in KNM-WT 17000: very small cranial capacity; low posterior profile of the calvaria; nasals extended far above the frontomaxillar suture and well onto an uninflated glabella; and extremely convex inferolateral margins of the orbits such as found in some gorillas."
- Kennedy 1991: As for the maximum parietal breadth and the biauriculare in O.H.5 and KNM-ER 406 "the robust australopithecines have values near the Gorilla mean: both the pongids and the robust australopithecines have highly pneumatized b...
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