Questions surrounding human evolution and migration are a source of constant interest to archaeologists around the globe. Three new studies, focused on different times and places, are providing fresh insight into the early spread and arrival of humans, from the first hominin footprints on Crete, to Pleistocene Homo sapiens in Indonesia, and signs of pre-European human presence on the Falkland Islands (below).
Fossilised footprints on Crete
Researchers studying a set of fossilised footprints on the Greek island of Crete have discovered that they are more than six million years old. The group of over 50 prints, believed to belong to an early hominin, was discovered near the village of Trachilos in western Crete (below) in 2017. Now, new dating has revealed that they were created 6.05 million years ago, c.350,000 years earlier than originally believed, potentially making them the oldest direct evidence of a human-like foot used for bipedal walking ever found.
The footprints (above) have several characteristics that are unique to humans, including the presence of a forefoot ball and a non-opposable big toe that sits on the end of the foot next to the other toes, while other observable traits are also found in primates, such as a non-bulbous heel, proportionately shorter sole, and lack of a longitudinal medial arch. Although researchers have acknowledged the need for caution as no body fossils have been found, and other archaeologists have expressed some scepticism, the team behind the latest work suggests that the creator of the Trachilos footprints can be identified provisionally as a primitive, bipedal hominin.
Regardless of where exactly they fall in the phylogenetic tree, these tracks represent a source of information that could be crucial to our understanding of early hominin evolution. However, a precise age was necessary in order to better understand their significance. Stratigraphic dating was carried out when the prints were first reported in 2017, but the new research, recently published in Scientific Reports, used palaeomagnetic and micropaleontological methods to produce the date of 6.05 million years ago. This makes the prints the same age as the fossils of Orrorin tugenensis from Kenya, which is the oldest known upright-walking biped in Africa. It is possible that the Trachilos prints were created by a species that developed in parallel to O tugenensis and that together they represent the earliest evidence of bipedal hominids.
Although uncertainty remains about the precise relationship between the creators of the Trachilos footprints and other early hominins, the recent dating work opens new avenues for future research.
Pleistocene people on Sulawesi
The island of Sulawesi has produced many significant insights into early human activity in Indonesia, including the world’s oldest piece of representational rock art, dating to at least 45,500 years ago (see CWA 106), but the discovery of a fragment of human jawbone in Leang Bulu Bettue cave in south-western Sulawesi represents the first human skeletal remains from the Pleistocene period found on the island. Although modern humans are thought to have arrived in the region by 70-50,000 years ago, there are currently only a few Late Pleistocene sites attributed to Homo sapiens in Indonesia, and fossil evidence of their presence is also very rare.
The Leang Bulu Bettue fossil, which was found during excavations in 2017, has now been dated to between 24,800 and 16,000 years ago using material from the sediment layer in which it was found, including isotope analysis of stalagmites, radiocarbon dating of shells, laser ablation of a pig tooth, and optical dating of feldspar grains.
The right maxilla (below) is so fragmentary that archaeologists could not discover much about this individual beyond the fact that they were an adult, and that they had fairly poor oral health. However, the surviving teeth do exhibit unusual dental wear that may potentially be related to a nondietary use such as the production of twine from palm fronds. Despite its fragile nature, the discovery offers the first direct fossil insight into how early H sapiens on Sulawesi interacted with their environment at this time.
The fossil was found in a layer associated with material from domestic activities such as stone artefact production and food preparation, as well as pieces of portable art and signs of pigment use that serve as a reminder that this individual may have been part of the population responsible for some of the world’s oldest rock art, suggesting that the artistic tradition in southern Sulawesi existed from at least 45,500 years ago until the Last Glacial Maximum (c.23,000 years ago). No other evidence of human burial has been found in this layer yet, but the presence of the jawbone leads archaeologists to hope that further remains may be found during future excavations.
Early visitors to the Falkland Islands?
When Charles Darwin visited the Falklands in 1833, he was puzzled by the presence of the islands’ only terrestrial mammal, the ‘warrah’ or Dusicyon australis. This wolf-like animal was driven to extinction by Europeans in 1876, but the question of how it originally reached the islands remains. The apparent absence of evidence for any pre-European human activity on the islands originally led to the conclusion that it must have evolved from a South American mainland species (Dusicyon avus) that crossed the South Atlantic during the Last Glacial Maximum. However, new research is giving credence to an alternative explanation – that the warrah diverged from D avus on the mainland and was brought to the islands by humans in the more recent past.
A new interdisciplinary study has identified several strands of evidence that point to human presence on the islands prior to the European arrival in 1690. The first is a projectile point found on New Island in 1979 that is made of locally sourced stone and matches the lithic technology used in Tierra del Fuego over the past 1,000 years. Second, in 2018, surveys near the point’s findspot identified seven deposits of disarticulated animal bones. Excavations of two of these deposits, dating to between c.745 and 600 years ago, determined that they appear to be midden or secondary processing sites composed mostly of sea lion and penguin, indicating that human hunting of these species took place on the island between AD 1275 and 1420.
Third, signs of ancient fires can be seen in spikes in charcoal levels in sediments. Analysis of a peat core from New Island shows significant increases c.1,000 years ago and from 620 to 470 years ago, while a previous peat record near Stanley also identified a noticeable increase from 5,470-3,570 years ago. Although fires can be caused by lightning strikes as well as humans, such weather is very rare on the Falkland Islands. Additionally, the patterns of these spikes directly mirror the increases that occurred c.250-190 years ago when Europeans first established settlements on the islands.
Finally, carbon and nitrogen isotope analysis of warrah bones from West Falkland (above) points to a marine-based diet relying heavily on sea lion and penguin, which may indicate a commensal relationship with humans. The oldest warrah bone has been dated to at least c.3,400 years ago; although this is considerably earlier than the fire and bone-pile evidence from New Island, when considered with the other charcoal evidence from Stanley, it does support the suggestion that humans may also have visited the Falkland Islands at earlier points in time, perhaps bringing the warrah with them. It is hoped that future work will shed more light on this intriguing question.
FURTHER READING
U Kirscher, H El Atfy, A Gärtner et al (2021) ‘Age constraints for the Trachilos footprints from Crete’, Scientific Reports (https://doi.org/10.1038/s41598-021-98618-0).
A Brumm, D Bulbeck, B Hakim et al (2021) ‘Skeletal remains of a Pleistocene modern human (Homo sapiens) from Sulawesi’, PLoS ONE (https://doi.org/10.1371/journal.pone.0257273).
K M Hamley, J L Gill, K E Krasinski et al (2021) ‘Evidence of prehistoric human activity in the Falkland Islands’, Science Advances (https://doi.org/10.1126/sciadv.abh3803).
