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The long limb bones of the StW 573 Australopithecus skeleton from Sterkfontein Member 2: Descriptions and proportions
- Source :
- Journal of Human Evolution, Journal of Human Evolution, Elsevier, 2019, 133, pp.167-197. ⟨10.1016/j.jhevol.2019.05.015⟩
- Publication Year :
- 2018
-
Abstract
- Due to its completeness, the A.L. 288-1 (Lucy) skeleton has long served as the archetypal bipedal Australopithecus. However, there remains considerable debate about its limb proportions. There are three competing, but not necessarily mutually exclusive, explanations for the high humerofemoral index of A.L. 288-1: (1) a retention of proportions from an Ardipithecus-like most recent common ancestor (MRCA); (2) indication of some degree of climbing ability; (3) allometry. Recent discoveries of other partial skeletons of Australopithecus, such as those of A. sediba (MH1 and MH2) and A. afarensis (KSD-VP-1/1 and DIK-1/1), have provided new opportunities to test hypotheses of early hominin body size and limb proportions. Yet, no early hominin is as complete (>90%), as is the 3.67 Ma Little Foot (StW 573) specimen, from Sterkfontein Member 2. Here, we provide the first descriptions of its upper and lower long limb bones, as well as a comparative context of its limb proportions. As to the latter, we found that StW 573 possesses absolutely longer limb lengths than A.L. 288-1, but both skeletons show similar limb proportions. This finding seems to argue against an allometric explanation for the limb proportions of A.L. 288-1. In fact, our multivariate allometric analysis suggests that limb lengths of Australopithecus, as represented by StW 573 and A.L. 288-1, developed along a significantly different (p < 0.001) allometric scale than that which typifies modern humans and African apes. Our analyses also suggest, as have those of others, that hominin limb evolution occurred in two stages with: (1) a modest increase in lower limb length and a concurrent shortening of the antebrachium between Ardipithecus and Australopithecus, followed by (2) considerable lengthening of the lower limb along with a decrease of both upper limb elements occurring between Australopithecus and Homo sapiens.
- Subjects :
- 0106 biological sciences
010506 paleontology
[SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory
[SHS.ANTHRO-BIO]Humanities and Social Sciences/Biological anthropology
Context (language use)
Body size
Mutually exclusive events
010603 evolutionary biology
01 natural sciences
Arm Bones
South Africa
Ardipithecus
Animals
0601 history and archaeology
Femur
Leg Bones
Ecology, Evolution, Behavior and Systematics
0105 earth and related environmental sciences
Australopithecus sediba
060101 anthropology
biology
Fossils
Hominidae
06 humanities and the arts
Anatomy
biology.organism_classification
Skeleton (computer programming)
Limb bones
Australopithecus
Archaeology
Homo sapiens
Anthropology
StW 573 (‘Little Foot’)Limb proportionsLimb indicesLocomotionEvolutionary trends
Allometry
Australopithecus afarensis
Subjects
Details
- ISSN :
- 10958606 and 00472484
- Volume :
- 133
- Database :
- OpenAIRE
- Journal :
- Journal of human evolution
- Accession number :
- edsair.doi.dedup.....fb59d60a1b05bc9b16d00f7f5f084894