Cave of Hearths from southern Africa. There is undoubtedly a gradation in morphology that makes it difficult to set the boundary between anatomically modern humans and H. heidelbergensis, but the variation in the later Homo fossil record is too great to be accommodated in a single taxon. Researchers who wish to make a distinction between fossils such as Florisbad and Laetoli 18 and subrecent and living modern humans either do so taxonomically by referring the former specimens to a separate species, Homo helmei Dreyer 1935, or they distinguish them informally as “archaic Homo sapiens.”
This grade grouping includes Pleistocene Homo taxa that lack the derived and distinctive size and shape of the modern human cranium and postcranial skeleton. Some individuals in these taxa possessed only medium-sized brains, yet they exhibit modern human-like body proportions. The first fossil taxon to be recognized in this grade is H. neanderthalensis King 1864, whose temporal range is ca. 200–28 ka (but if the Sima de los Huesos material is included, then it is ca. >450–28 ka). The first example of H. neanderthalensis to be discovered was a child’s cranium recovered in 1829 from a cave in Belgium called Engis, but the type specimen, the Neanderthal 1 skeleton, was found in 1856 at the Kleine Feldhofer Grotte in Elberfield, Germany. Fossil evidence for H. neanderthalensis has since been found in Europe as well as in the Near East, the Levant, and western Asia. The distinctive features of the cranium of H. neanderthalensis include thick, double-arched brow ridges, a face that projects anteriorly in the midline, a large nose, laterally projecting and rounded parietal bones, and a rounded, posteriorly projecting occipital bone.
Mandibular and dental features include a retromolar space, distinctively high incidences of some nonmetrical dental traits, and thinner tooth enamel than in modern humans. The average endocranial volume of H. neanderthalensis was the same as that of contemporary H. sapiens, but it is larger than that of living modern humans. Postcranially, H. neanderthalensis individuals were stout with a broad rib cage, a long clavicle, a wide pelvis, and limb bones that are generally robust with well-developed muscle insertions. The distal extremities tend to be short compared with most modern H. sapiens, but H. neanderthalensis was evidently an obligate biped. The generally well-marked muscle attachments and the relative thickness of long bone shafts point to a strenuous lifestyle. For some researchers the H. neanderthalensis hypodigm is restricted to fossils from Europe and the Near East that used to be referred to as “Classic” Neanderthals. Others interpret the taxon more inclusively and include fossil evidence that is generally older and less distinctive (e.g., Steinheim,