The Trachilos footprints are possibly tetrapod footprints from the late Miocene on the western Crete, close to the village of Trachilos, west of Kissamos, in the Chania Prefecture. Some researchers described the tracks as representing at least one apparent bipedal hominin or an unknown primate. The stratum in which the footprints were found was dated to about 5.7 million years ago, which predates the previously earliest discovered hominin footprints by about two million years. Later studies show that the footprints might be more than 6 million years old. The researchers of the tracks suggest that it may imply the possibility of early hominin presence outside of Africa. However, there is no consensus that these impressions are distinct enough to confidently assign to a primate or even a vertebrate, or that they are indeed footprints at all.
Discovery The tracks were originally discovered by Gerard D. Gierliński, from the Polish Research Institute in Warsaw in 2002. During a visit to Trachilos on Crete, Gierliński found the tracks, and as he was not planning on staying in Trachilos, he recorded the footprints to investigate them in the future. In 2012 Gierliński received permission from the Greek government to research the area, returning to Trachilos with other researchers to explore the tracks in detail. The researchers used methods such as laser scans and 3D imaging of the footprints, and compared them to apes and bears as well as humans.
Dates The tracks were dated by using the underlying rock bed, predominantly sedimentary, and foraminifera. The study explains, "The coastal rocks at Trachilos[,] lie within the Platanos Basin, and present a succession of shallow marine late Miocene carbonates and siliciclastics[...] At the top, this marine succession terminates abruptly in the coarse-grained terrigenous sedimentary rocks of the Hellenikon Group[.]" The study continues, stating that the sedimentary rocks would have been created around 5.6 million years ago, at the time of the Messinian salinity crisis (mya). The researchers also found evidence of foraminifera, which were dated at 8.5 mya and 3.5 mya. Given the date of the sedimentary rocks and the foraminifera samples, the researches created an approximate interval of 8.5 mya to 5.6 mya. As the rock sediment containing the tracks resembled that of Hellenikon minerals, the tracks were estimated to be 5.7 mya within the given interval. In 2021, further research was published in regard to dating by Kirscher et al. Cyclostratigraphic data based on magnetic susceptibility indicated that the Trachilos footprints are about 6.05 Ma old, which is 350,000 years older than was found previously. This puts the Trachilos footprints in the same period as the fossils of Orrorin tugenensis from Kenya.
Characteristics The footprints were measured to range at 94-223 mm (3.7-8.8 inches) long and determined to be oriented in a south-west direction. There are clear pressure indexes, resembling that of a modern Homo sapiens plantigrade structure. The researchers also determined the presence of five digits in the imprints, classifying the track maker as pentadactyl, and lacking claws. As there was no visible evidence of forelimbs from the tracks, the track maker was identified as bipedal. Through 3D printing and laser scanning, there are impressions found which indicate a ball region, a pulling up motion of the foot, a hallux, and small possible gaps between the first and other digit impressions. Poorly preserved prints lack these gaps, however. The lateral digit impressions become progressively smaller so that the digital region as a whole is strongly asymmetrical. The impression of the hallux has a narrow neck and bulbous asymmetrical distal pad, indicating that the tracks were entaxonic. Morphometric analysis showed the footprints to have outlines that are distinct from modern non-hominin primates and resemble those of hominins. While younger than fossil records of hominins such as Sahelanthropus, found in Chad and dated around seven million years ago, the discovery potentially challenges the generally accepted theory that all early hominins were only present in Africa. The print morphology suggests that the trackmaker could be a basal member of the clade Hominini, but as Crete is some distance outside the known geographical range of pre-Pleistocene hominins, researchers say that there is also a possibility that they represent a hitherto unknown late Miocene primate that convergently evolved human-like foot anatomy.
… excerpt ends here. Continue reading the full article.
