Researchers have discovered footprints preserved in volcanic ash at an ancient lakebed in Africa that challenge current understanding of hominin evolution. The tracks, dated to approximately 1.4 million years ago, show characteristics that don't align neatly with known species like Paranthropus boisei or Homo erectus, the dominant hominins of that era.
The discovery comes from Engare Sero in northern Tanzania, where a group of eight individuals walked across soft mud during the middle Pleistocene. Scientists analyzed the depth, spacing, and morphology of the prints to determine the walkers' body size and gait. The footprints display anatomical features distinct from both P. boisei, a robust australopithecine, and H. erectus, an early human ancestor.
The prints suggest the walkers had relatively large feet and exhibited a bipedal gait consistent with hominin locomotion. However, specific measurements and proportions don't match fossil evidence or footprint records from either species during that time period. This raises the possibility of an as-yet unidentified hominin species present in East Africa, or represents variation within a known species that scientists haven't previously documented.
The volcanic ash overlaying the footprints provides reliable dating through radiometric analysis, anchoring the evidence firmly in time. Such well-preserved tracks offer rare direct evidence of ancient behavior and anatomy, avoiding the gaps inherent in skeletal records.
The findings add complexity to the hominin fossil record at a critical evolutionary moment. Around 1.4 million years ago, H. erectus was dispersing across Africa and into Asia while P. boisei occupied the same region. This discovery suggests the picture may be more complicated than current taxonomies indicate.
Researchers emphasize the need for additional footprints and skeletal remains to clarify which species made the Engare