They have identified an ancestral human species that coexisted with it through foot bone fossils

Identifying some mysterious bone fossils from the feet of a human who lived before that 3.4 million years It allowed us to solve a mystery that had been open since 2009. The remains belong to a different species than the one found in the famous fossil. Lucythe first Almost complete skeleton of australopithecines Found in 1974, which means it Two species of human ancestors coexisted At the same time and in the same area.

In 2009, a team of scientists led by Johannes Haile Selassie, a paleontologist at Arizona State University, discovered Eight foot bones of an ancient human ancestor In 3.4 million-year-old sediments in the Afar Rift in Ethiopia. The fossil called “Portelli ft“, was discovered at the Woranso-Mille excavation site and reported in an article published in 2012.

In 2015, the group described a new species, Australopithecus dieremidafrom fossils from the same region, but did not include the foot within this type. After more than a decade of additional fieldwork and the discovery of new remains, the authors believe they can reliably link these remains to A. deyiremeda.

The Woranso-Mille site is of particular interest because it is the only place where there is clear evidence of two related species of humans coexisting simultaneously in the same area. Portelli’s foot, which belongs to A. deyiremeda, is The most primitive Lucy’s type, Australopithecus afarensis.

keep b Reversible big toea crucial trait for climbing, but on land A. deyiremeda moves bipedal. In all likelihood, the gait was propelled with the second toe rather than the big toe, as occurs in modern humans. This indicates that Bipedalism in early humans took various forms before settling on the current style.

To investigate the diet of A. deyiremeda, eight of the 25 teeth found in Portelli areas were subjected to isotopic analysis, with only tooth enamel sampled. The results show that while Lucy species were mixed consumers of C3 resources (Trees and shrubs) and C4 terminals (Tropical and woody herbs), A. deyiremeda relied mainly on C3-type resources.

The carbon isotopic profile is similar to that observed in ancient hominins, such as Ardipithecus ramidus and Australopithecus anamensis, suggesting that A. deyiremeda It did not exploit the same spectrum of resources From A. afarensis.

Another essential aspect of the research was to accurately determine the age of the fossils and reconstruct the ancient environment in which these humans lived. Detailed fieldwork at Woranso-Mille allowed us to determine the stratigraphic relationships between the remains, which is crucial for determining when and under what environmental conditions different species coexisted.

In addition to the 25 teeth found at Portelli, Haile Selassie’s team recovered a jaw Young individual Which, based on the anatomy of the teeth, clearly belongs to A. deyiremeda. This jaw preserves all the baby teeth that have already emerged, along with several permanent teeth growing within the lower jaw bone, which allowed us to estimate that the individual’s age was about 4.5 years old at the time of death.

CT analysis of the formed teeth reveals an uneven pattern of development between the incisors and molars, similar to that observed in modern great apes and in other early australopithecines such as Lucy species. Despite growing evidence of the diversity of these early australopithecines—in body size, diet, locomotion, and anatomy—the data suggest that they shared very similar growth patterns.

Knowing how these ancient ancestors moved and what they ate allows us to better understand how different species coexisted without driving each other to extinction. Studying these ecosystems millions of years ago not only answers questions about our origins, but also provides keys to explaining current and future processes, such as climate shifts.

phenomena Climate change Compared to those observed today that actually occurred in the time of Luce and A. Derimida, lessons learned from that period could contribute to mitigating some of the more negative impacts of contemporary climate change.