TY - JOUR
T1 - From australopithecus to homo
T2 - The transition that wasn’t
AU - Kimbel, William
AU - Villmoare, Brian
N1 - Publisher Copyright:
© 2016 The Author(s) Published by the Royal Society. All rights reserved.
PY - 2016/7/5
Y1 - 2016/7/5
N2 - Although the transition from Australopithecus to Homo is usually thought of as a momentous transformation, the fossil record bearing on the origin and earliest evolution of Homo is virtually undocumented. As a result, the poles of the transition are frequently attached to taxa (e.g. A. afarensis, at ca 3.0 Ma versus H. habilis or H. erectus, at ca 2.0-1.7 Ma) in which substantial adaptive differences have accumulated over significant spans of independent evolution. Such comparisons, in which temporally remote and adaptively divergent species are used to identify a ‘transition’, lend credence to the idea that genera should be conceived at once as monophyletic clades and adaptively unified grades. However, when the problem is recast in terms of lineages, rather than taxa per se, the adaptive criterion becomes a problem of subjectively privileging ‘key’ characteristics from what is typically a stepwise pattern of acquisition of novel characters beginning in the basal representatives of a clade. This is the pattern inferred for species usually included in early Homo, including H. erectus, which has often been cast in the role as earliest humanlike hominin. A fresh look at brain size, hand morphology and earliest technology suggests that a number of key Homo attributes may already be present in generalized species of Australopithecus, and that adaptive distinctions in Homo are simply amplifications or extensions of ancient hominin trends.
AB - Although the transition from Australopithecus to Homo is usually thought of as a momentous transformation, the fossil record bearing on the origin and earliest evolution of Homo is virtually undocumented. As a result, the poles of the transition are frequently attached to taxa (e.g. A. afarensis, at ca 3.0 Ma versus H. habilis or H. erectus, at ca 2.0-1.7 Ma) in which substantial adaptive differences have accumulated over significant spans of independent evolution. Such comparisons, in which temporally remote and adaptively divergent species are used to identify a ‘transition’, lend credence to the idea that genera should be conceived at once as monophyletic clades and adaptively unified grades. However, when the problem is recast in terms of lineages, rather than taxa per se, the adaptive criterion becomes a problem of subjectively privileging ‘key’ characteristics from what is typically a stepwise pattern of acquisition of novel characters beginning in the basal representatives of a clade. This is the pattern inferred for species usually included in early Homo, including H. erectus, which has often been cast in the role as earliest humanlike hominin. A fresh look at brain size, hand morphology and earliest technology suggests that a number of key Homo attributes may already be present in generalized species of Australopithecus, and that adaptive distinctions in Homo are simply amplifications or extensions of ancient hominin trends.
KW - Australopithecus
KW - Early homo
KW - Transition
UR - http://www.scopus.com/inward/record.url?scp=84974661240&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84974661240&partnerID=8YFLogxK
U2 - 10.1098/rstb.2015.0248
DO - 10.1098/rstb.2015.0248
M3 - Review article
C2 - 27298460
AN - SCOPUS:84974661240
SN - 0962-8436
VL - 371
JO - Philosophical Transactions of the Royal Society B: Biological Sciences
JF - Philosophical Transactions of the Royal Society B: Biological Sciences
IS - 1698
M1 - 20150248
ER -