Senzilles

Senzilles refers to a hypothetical ancestral human species that is proposed to have existed before the split of the lineage leading to modern humans from the lineage leading to chimpanzees and bonobos. The term "senzilles" is derived from the Latin word "senex," meaning old, and "illes," meaning those. It suggests an ancient, primitive ancestor.

The concept of senzilles is part of evolutionary theory and paleoanthropology, aiming to reconstruct the stages of hominin evolution. Scientists theorize that a species like senzilles would have possessed traits intermediate between the last common ancestor with apes and the earliest known hominins. This hypothetical ancestor is thought to have been arboreal to some extent, but may have also shown adaptations for terrestrial locomotion, possibly bipedalism, though likely less efficient than in later hominins.

Evidence for senzilles is indirect, primarily inferred from comparative anatomy and genetics of modern apes and humans, as well as from the fossil record of early hominins. Fossil discoveries like *Sahelanthropus tchadensis*, *Orrorin tugenensis*, and *Ardipithecus ramidus* are considered candidates for species that might represent or be closely related to the senzilles stage. These fossils exhibit a mosaic of ape-like and human-like features, supporting the idea of a gradual transition.

Understanding the senzilles stage is crucial for tracing the origins of human bipedalism, tool use, and cognitive abilities. However, as a hypothetical ancestor, definitive proof of senzilles as a distinct species remains elusive, and its exact characteristics and place in the evolutionary timeline are subjects of ongoing research and debate among scientists.