What constitutes Homo sapiens? Morphology versus received wisdom

Area of Science:

• Paleoanthropology
• Human Evolution
• Taxonomy

Background:

• The definition of Homo sapiens has evolved since Linnaeus coined the term.
• Early definitions relied on morphology, but later classifications shifted to geological age.
• The introduction of terms like "archaic" (AS) and "anatomically modern" (AMS) complicated species identification.

Observation:

• Morphological differences between fossil specimens have historically led to varied taxonomic assignments.
• Mayr's 1950 classification collapsed diverse human fossils into Homo, simplifying evolutionary history.
• Current paleoanthropological practice often uses geological age over morphology to define species like Homo erectus and Homo sapiens.

Findings:

• Many fossils classified as AMS and all AS are argued not to be Homo sapiens.
• Upper Paleolithic humans (e.g., Cro-Magnon) are exceptions, potentially belonging to Homo sapiens.
• Shared features between some AMS fossils and extant humans (ES) suggest a distinct sapiens clade.

Implications:

• The current definition of Homo sapiens may be too broad, encompassing morphologically dissimilar specimens.
• Re-evaluating fossil classifications is necessary to accurately delineate the Homo sapiens species.
• Discoveries like Homo floresiensis and recent Chinese fossils challenge assumptions about recent human evolution and species identification.