Sahelinia

Sahelinia is an extinct genus of hominin that lived approximately 7 million years ago, based on the discovery of a single skull fragment, TM 266-01-060-1, nicknamed "Toumaï." The fossil was discovered in the Djurab Desert of Chad in 2001 by a Franco-Chadian team led by Michel Brunet. Sahelinia tchadensis is the only species within the genus.

The significance of Sahelinia lies in its potential position near the root of the hominin evolutionary tree, representing one of the earliest known species after the split between the human and chimpanzee lineages. Its discovery challenged previous assumptions about hominin origins being confined to East Africa, suggesting a broader geographic distribution.

The "Toumaï" skull exhibits a mosaic of features, including a small cranial capacity (estimated at 360-370 cc), a massive brow ridge, a relatively flat face, and a foramen magnum positioned further forward than in apes, suggesting a possibly bipedal posture.

However, the interpretation of Sahelinia remains controversial. The fragmentary nature of the fossil evidence, particularly the lack of postcranial remains (bones from below the skull), makes it difficult to definitively determine its locomotor behavior and its precise relationship to other early hominins. Some researchers argue that Sahelinia may be a more primitive hominid, or even an ape with convergent features to early hominins, while others maintain its status as a crucial piece of evidence for understanding the early stages of human evolution. Further fossil discoveries are needed to clarify its evolutionary position and its place in the hominin family tree.