Postcranial evidence from early Homo from Dmanisi, Georgia

Abstract

The Plio-Pleistocene site of Dmanisi, Georgia, has yielded a rich fossil and archaeological record documenting an early presence of the genus Homo outside Africa. Although the craniomandibular morphology of early Homo is well known as a result of finds from Dmanisi and African localities, data about its postcranial morphology are still relatively scarce. Here we describe newly excavated postcranial material from Dmanisi comprising a partial skeleton of an adolescent individual, associated with skull D2700/D2735, and the remains from three adult individuals. This material shows that the postcranial anatomy of the Dmanisi hominins has a surprising mosaic of primitive and derived features. The primitive features include a small body size, a low encephalization quotient and absence of humeral torsion; the derived features include modern-human-like body proportions and lower limb morphology indicative of the capability for long-distance travel. Thus, the earliest known hominins to have lived outside of Africa in the temperate zones of Eurasia did not yet display the full set of derived skeletal features.

Locomotor anatomy and biomechanics of the Dmanisi hominins

“…This suggests the Dmanisi hominins were not under heat stress and did not have the larger body and brain size associated with African H. ergaster or H. erectus sensu lato. However, the numerous manuports and stone tools found at Dmanisi, as well as evidence for butchery in the form of cut marks on bovid long bones (Lordkipanidze et al, 2007), indicate some degree of carnivory in these hominins. Thus, the Dmanisi hominins provide an opportunity to test the hypothesis that the locomotor adaptations evident in early Homo are related to foraging demands, rather than climate or size-related pressures.…”

“…Recent finds from the Georgian site of Dmanisi, dated to the earliest Pleistocene at 1.77 million years ago (Lordkipanidze et al, 2007), provide an important new perspective on this debate and the origin of our genus. The site of Dmanisi is located in a northern temperate climate (41 North latitude) in a region that currently maintains a climate that is approximately 17 C cooler than the Turkana basin of Kenya (see Supplementary Information), where many early Pliocene specimens of African H. erectus have been recovered.…”

“…In contrast, members of the genus Homo possess a suite of derived post-cranial traits associated with greater cursoriality, including longer hind limbs, shorter pedal phalanges, and a rigid longitudinal plantar arch (Shipman and Walker, 1989;Aiello and Dean, 1990;Bramble and Lieberman, 2004). Recently, we reported new post-cranial fossils for hominins from the site of Dmanisi that possess a mix of primitive and derived features (Lordkipanidze et al, 2007). In this paper, we assess the locomotor mechanics and energetics of these hominins and discuss the selection pressures shaping the transition from Australopithecus to Homo.…”

“…The site of Dmanisi is located in a northern temperate climate (41 North latitude) in a region that currently maintains a climate that is approximately 17 C cooler than the Turkana basin of Kenya (see Supplementary Information), where many early Pliocene specimens of African H. erectus have been recovered. The fossil hominins at Dmanisi retain a number of primitive features, including a relatively small brain (Vekua et al, 2002;Rightmire et al, 2006) and small stature (Lordkipanidze et al, 2007), compared with penecontemporary African H. erectus. This suggests the Dmanisi hominins were not under heat stress and did not have the larger body and brain size associated with African H. ergaster or H. erectus sensu lato.…”

The energetic significance of cooking

“…) habilis have a complex relationship that includes a temporal overlap in East Africa of around half a million years (~1.9 to 1.44 mya; Spoor et al, 2007), and a less clear distinction in body mass and relative brain size than formerly thought (Spoor et al, 2007;Lordkipanidze et al, 2007;Lieberman, 2007). For instance some anatomically defined H. erectus in Georgia are in the size range of H. (A.…”