Preserving the impossible: conservation of soft-sediment hominin footprint sites and strategies for three-dimensional digital data capture.

Human footprints provide some of the most publically emotive and tangible evidence of our ancestors. To the scientific community they provide evidence of stature, presence, behaviour and in the case of early hominins potential evidence with respect to the evolution of gait. While rare in the geological record the number of footprint sites has increased in recent years along with the analytical tools available for their study. Many of these sites are at risk from rapid erosion, including the Ileret footprints in northern Kenya which are second only in age to those at Laetoli (Tanzania). Unlithified, soft-sediment footprint sites such these pose a significant geoconservation challenge. In the first part of this paper conservation and preservation options are explored leading to the conclusion that to 'record and digitally rescue' provides the only viable approach. Key to such strategies is the increasing availability of three-dimensional data capture either via optical laser scanning and/or digital photogrammetry. Within the discipline there is a developing schism between those that favour one approach over the other and a requirement from geoconservationists and the scientific community for some form of objective appraisal of these alternatives is necessary. Consequently in the second part of this paper we evaluate these alternative approaches and the role they can play in a 'record and digitally rescue' conservation strategy. Using modern footprint data, digital models created via optical laser scanning are compared to those generated by state-of-the-art photogrammetry. Both methods give comparable although subtly different results. This data is evaluated alongside a review of field deployment issues to provide guidance to the community with respect to the factors which need to be considered in digital conservation of human/hominin footprints

Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa.

Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa

Footprint evidence of early hominin locomotor diversity at Laetoli, Tanzania

Bipedal trackways discovered in 1978 at Laetoli site G, Tanzania and dated to 3.66 million years ago are widely accepted as the oldest unequivocal evidence of obligate bipedalism in the human lineage1-3. Another trackway discovered two years earlier at nearby site A was partially excavated and attributed to a hominin, but curious affinities with bears (ursids) marginalized its importance to the paleoanthropological community, and the location of these footprints fell into obscurity3-5. In 2019, we located, excavated and cleaned the site A trackway, producing a digital archive using 3D photogrammetry and laser scanning. Here we compare the footprints at this site with those of American black bears, chimpanzees and humans, and we show that they resemble those of hominins more than ursids. In fact, the narrow step width corroborates the original interpretation of a small, cross-stepping bipedal hominin. However, the inferred foot proportions, gait parameters and 3D morphologies of footprints at site A are readily distinguished from those at site G, indicating that a minimum of two hominin taxa with different feet and gaits coexisted at Laetoli

Geo-archaeological and geometrically corrected reconstruction of the 1.84 Ma FLK Zinj paleolandscape at Olduvai Gorge, Tanzania

A geomorphological, sedimentological, stratigraphic, and geometric study of 30 trenches excavated around FLK Zinj (Bed I, Olduvai Gorge) has enabled the partial reconstruction of the paleolandscape surrounding this site for a radius of ∼1000 m. This is the largest sample of geological and archaeological information yet available to reconstruct the topography, ecology, and geomorphology of the Zinj paleosurface and the hominin activities preserved within it. Contrary to previous interpretations, which place FLK Zinj on an isolated and narrow peninsula, it appears that the site was located on the edge of an elevated platform traceable for hundreds of meters. Hominins created FLK Zinj (and other sites, such as the recently discovered PTK and AMK) within the wooded habitats of this platform rather than the more open and grassy environments situated on lower portions of the lacustrine floodplain. Input areas, probably in the form of alluvial fans, existed to the south, following a North-South direction. These input areas are partially responsible for changes in the type sequence. Restricted erosion documented on the wooded platform was mostly caused by runoff processes. An archaeological study of the excavated trenches reveals a sharp contrast in fossil and stone tool density between FLK Zinj and the surrounding landscape, further supporting the contention that the site may have acted as a “central place” where repeated carcass transport, butchery, and consumption took place. Taphonomic studies indicate that at this stage of human evolution, hominins had primary access to carcasses and were not dependent on other carnivores for obtaining meat

Autochthony and orientation patterns in Olduvai Bed I: a re-examination of the status of post-depositional biasing of archaeological assemblages from FLK North (FLKN)

International audienceRecent excavations at FLK North (Olduvai Gorge, Tanzania) have produced new information on the orientation of archaeological materials at various levels of the site. This information includes the uniform distribution of material azimuths, which contrasts with previous inferences of highly patterned orientations of materials in the Bed I archaeological sites. Those previous inferences of patterned material orientations are based on Mary Leakey's 50-year-old drawings of artifact and fossil bone distribution, but are not verified by our precise measurements of archaeological objects made in situ. Nor do those previous results agree with the general lack of geological, geomorphological, and/or taphonomic data that would indicate significant post-depositional movement of archaeological materials in the sites. We argue here that Leakey's drawings are incomplete (only portions of each assemblage were drawn) and inaccurate in their representation of the original locations, shapes and orientations of most archaeological specimens. This argument is supported by several important mismatches in object representations between a photograph taken of a small portion of the FLK 22 Zinjanthropus site floor before the removal of the archaeological items, and the sketch of the same area drawn by Leakey. Thus, we conclude that primary orientation data of excavations (i.e., direct measurements taken from items) generated prior to object removal are the only valid indicators of the relative isotropy or anisotropy of these important paleoanthropological assemblages

Autochthony and orientation patterns in Olduvai Bed I: a re-examination of the status of post-depositional biasing of archaeological assemblages from FLK North (FLKN)

Recent excavations at FLK North (Olduvai Gorge, Tanzania) have produced new information on the orientation of archaeological materials at various levels of the site. This information includes the uniform distribution of material azimuths, which contrasts with previous inferences of highly patterned orientations of materials in the Bed I archaeological sites. Those previous inferences of patterned material orientations are based on Mary Leakey's 50-year-old drawings of artifact and fossil bone distribution, but are not verified by our precise measurements of archaeological objects made in situ. Nor do those previous results agree with the general lack of geological, geomorphological, and/or taphonomic data that would indicate significant post-depositional movement of archaeological materials in the sites. We argue here that Leakey's drawings are incomplete (only portions of each assemblage were drawn) and inaccurate in their representation of the original locations, shapes and orientations of most archaeological specimens. This argument is supported by several important mismatches in object representations between a photograph taken of a small portion of the FLK 22 Zinjanthropus site floor before the removal of the archaeological items, and the sketch of the same area drawn by Leakey. Thus, we conclude that primary orientation data of excavations (i.e., direct measurements taken from items) generated prior to object removal are the only valid indicators of the relative isotropy or anisotropy of these important paleoanthropological assemblages

Homo naledi, a new species of the genus Homo

Homo naledi es una especie previamente desconocida de homínido extinto descubierta dentro de la Cámara Dinaledi del sistema de cuevas Rising Star, en el Cradle of Humankind, Sudáfrica. Esta especie se caracteriza por tener una masa corporal y estatura similar a las poblaciones humanas de cuerpo pequeño, pero un volumen endocraneal pequeño similar al de los australopitecos. La morfología craneal de H. naledi es única, pero se asemeja más a las especies tempranas de Homo, incluyendo Homo erectus, Homo habilis o Homo rudolfensis. Aunque primitiva, la dentición es generalmente pequeña y simple en su morfología oclusal. H. naledi presenta adaptaciones manipulativas de la mano y la muñeca similares a las humanas. También exhibe un pie y miembro inferior similares a los humanos. Estos aspectos humanos se contrastan en el postcráneo con un tronco, hombro, pelvis y fémur proximal más primitivos o similares a los australopitecos. Representando al menos 15 individuos con la mayoría de los elementos esqueléticos repetidos múltiples veces, esta es la mayor colección de una sola especie de homínidos descubierta en África.National Geographic SocietyThe National Research Foundation of South Africa (WARF)The Palaeontological Scientific TrustLyda Hill FoundationWisconsin Alumni Research Foundation (WARF)Texas A and M UniversityDepto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu