Locomotor anatomy and biomechanics of the Dmanisi hominins

Abstract

The Dmanisi hominins inhabited a northern temperate habitat in the southern Caucasus, approximately 1.8 million years ago. This is the oldest population of hominins known outside of Africa. Understanding the set of anatomical and behavioral traits that equipped this population to exploit their seasonal habitat successfully may shed light on the selection pressures shaping early members of the genus Homo and the ecological strategies that permitted the expansion of their range outside of the African subtropics. The abundant stone tools at the site, as well as taphonomic evidence for butchery, suggest that the Dmanisi hominins were active hunters or scavengers. In this study, we examine the locomotor mechanics of the Dmanisi hind limb to test the hypothesis that the inclusion of meat in the diet is associated with an increase in walking and running economy and endurance. Using comparative data from modern humans, chimpanzees, and gorillas, as well as other fossil hominins, we show that the Dmanisi hind limb was functionally similar to modern humans, with a longitudinal plantar arch, increased limb length, and human-like ankle morphology. Other aspects of the foot, specifically metatarsal morphology and tibial torsion, are less derived and similar to earlier hominins. These results are consistent with hypotheses linking hunting and scavenging to improved walking and running performance in early Homo. Primitive retentions in the Dmanisi foot suggest that locomotor evolution continued through the early Pleistocene. Dear Author, Any queries or remarks that have arisen during the processing of your manuscript are listed below and highlighted by flags in the proof. Please check your proof carefully and mark all corrections at the appropriate place in the proof (e.g., by using on-screen annotation in the PDF file) or compile them in a separate list.For correction or revision of any artwork, please consult http://www.elsevier.com/artworkinstructions.Articles in Special Issues: Please ensure that the words 'this issue' are added (in the list and text) to any references to other articles in this Special Issue.Uncited references: References that occur in the reference list but not in the text e please position each reference in the text or delete it from the list.Missing references: References listed below were noted in the text but are missing from the reference list e please make the list complete or remove the references from the text. Location in articleQuery / remark Please insert your reply or correction at the corresponding line in the proof Q1Kindly check the affiliations. Q2Please check the hierarchy of section headings. Q3The following references have been changed to match the reference list: " Hermann et al., 1998" to "Hermann and Egund, 1998""Geissman (1986" to "Geissmann (1986)""Harcourt-Smith and Aeillo, 2004" to "Harcourt-Smith and Aiello, 2004". Please verify. Q4Please check the placement of footnotes citations 1e4 have been made at the end of the sentence "Parsing the independent effects." Please c...

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“…We have previously demonstrated that the same pattern is found for the femur; i.e., A.L. 288-1 and LB1 fall near the human OLS and/or RMA slopes for femoral length on body mass 1/3 (Franciscus and Holliday 1992; Holliday and Franciscus 2009; and see Figure 3a in Pontzer et al 2010). This who was in all likelihood heavier, deviates only -2.2% in humerus length from what would be expected for a recent human of her small body size following an OLS regression model.…”

Allomaternal care, life history and brain size evolution in mammals

“…Building on earlier ideas (Martin, 1983(Martin, , 1996Aiello and Key, 2002;Aiello and Wells, 2002;Leonard et al, 2003), we showed which of these factors are supported by general relationships that are also found in other mammalian lineages, and argued that special pleading for humans is not needed. These factors include the stabilization of energy intake on a higher level through a change in diet and cognitive and physiological buffering of seasonality effects (van Woerden et al, 2010(van Woerden et al, , 2012 as well as a reduction of energy spent on locomotion through abandonment of climbing and a more efficient bipedalism (Pontzer et al, 2010). The present study suggests that energy subsidies for mothers and infants play a major role in the stabilization of energy intake.…”

Earliest fire in Africa: towards the convergence of archaeological evidence and the cooking hypothesis

“…But with more recent finds the curve has tended to smooth out (Schoenemann 2006). The key points appear to be that brain size had already reached 1000 cm 3 one million years ago, that major tooth size reduction in Homo had already happened by 1.7 Ma and that changes to more modern body form came soon afterwards (being achieved by 1.5 Ma as shown by the Nariokotome specimen (Pontzer et al 2010). Certainly, the archaeological record around Lake Turkana shows hominins ranging widely on landscapes that were often semi-arid and offered no prospect of the kind of stable diet of fruits and herbs available to chimpanzees (Bunn and Ezzo 1993;Bunn 1994;Isaac and Behrensmeyer 1997) and much the same can be said for Olduvai (Blumenschine et al 2003).…”

“…Similar factors would seem to apply to varieties of Homo erectus beyond Africa. Although early Homo from Dmanisi in Georgia retains primitive features at 1.8 Ma, and is relatively small bodied, it had already acquired adaptations for striding locomotion and its toothwear patterns suggest a broadening of diet (Pontzer et al 2010(Pontzer et al , 2011. By this time, it can now be seen, the distribution of early Homo was so wide that it is certain that it must have mastered many environments (Clark 1993: 160) and sleeping in trees could not always have been an option.…”