Dali (fossil)

The Dali Skull, or Dali Man (Chinese: 大荔人), is a nearly complete fossilized skull, probably representing an early form of Archaic Homo sapiens which lived in the Late Middle Pleistocene period. It was discovered by Shuntang Liu in 1978 in Dali County in the Shaanxi Province of China.

The dating of the skull has been a subject of debate. Uranium-series dating of ox teeth from the site obtained a date of 209,000 ±23,000 years,^[1] however, the nature of the association between the hominid cranium and the ox teeth remains uncertain.^[2] The fossil is considered to be the most complete skull of that time period found in China.^[3]

Access to Dali is restricted. The Dali cranium is currently housed in the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China.^[2]

Characteristics of the Dali fossil

The Dali cranium is interesting to modern anthropologists as it is possibly an ideal specimen of an archaic Homo sapiens. It has a mixture of traits from both Homo erectus and Homo sapiens.^[4] The details of the face and skull are however distinct from European Neanderthals and earlier European hominids like the finds from Petralona and Atapuerca.^[5]

Skull vault

The skull is low and long, though the posterior end of the skull is rounded, unlike the contemporary broad-based H. erectus or top-wide skull of modern humans. It does however bear a prominent sagittal crest, a trait found in H. erectus but in few modern humans. The brain appears to have been sitting mainly behind the face, giving an extremely low forehead. The cranial capacity is estimated to around 1 120 cc, at the lower end of the modern human range, and upper end of the H. erectus range. The base of the cranium is less robust than in H. erectus.^[6] The posterior margin lacks the heavy neck muscle attachment seen in that group. Unlike the distinct tubular form seen in H. erectus, the tympanic plate is thin and foreshortened, a condition similar to that of modern humans.^[7]

Unlike H. erectus skulls, the Dali skulls lack the "pinched" look between the face and the cranial vault.

Face

The face is topped by massive brow ridges. The ridges curve over each eye, unlike the straight bar-like ridges seen at the Peking man material from Zhoukoudian. The curvature is more similar structurally to the brow ridges in archaic humans from Europe and Africa. The cheek bones are delicate, and the nasal bone flattened, again a curious combination of traits.^[4] During fossilization, the upper jaw has been fractured and dislocated upwards, giving the cranium the appearance of having a very short face. If reconstructed, the face would be probably be similar in overall dimensions to that of the Jinniushan man skull.^[6]

Interpretation

There has been considerable debate regarding how to classify the fossil in terms of species, with some anthropologists insisting it to be a regional variant of Homo heidelbergensis and others categorizing it as an early representative of Homo sapiens, and as such there is no current consensus on the species status of the Dali fossil.^[8] Some anthropologists, notably many Chinese representatives, cite the characteristics of the Dali cranium and other similar Chinese fossils of that era as evidence for genetic continuity in modern H. sapiens today, as Dali's traits are commonly found in modern Chinese H. sapiens populations. In turn, it is often argued that modern Chinese humans did not evolve in Africa, but instead evolved in China from a separate lineage of H. erectus.^[9] This position is consistent with the "Multiregional hypothesis," which states that different human populations across the planet had evolved with current racial characteristics in separate environments, and is contrary to the popular "Recent single-origin hypothesis," which asserts that modern H. sapiens evolved solely in Africa and spread throughout the planet during a recent exodus.

Other possible Dali-type finds

An assortment of primitive Homo skulls have tentatively been placed with the Dali find. The Maba Man, a 120 to 140 000 year old fragmentary skull from Guangdong in China shows the same general contours of the forehead.^[10] A partial female skeleton with skull from Jinniushan (also China) seems to belong to the same group, characterized by a very robust skull cap but less robust skull base.^[11][12][13] A possibly fourth member could be the Narmada skull from the Madhya Pradesh in India, consisting of a single robust cranial vault.^[14]

The Denisova hominin, represented by a very robust finger bone found in the Altai mountains in Russia is quoted as likely linked to the Dali people. Surprisingly, DNA studies show the bone belong to a woman, with Mitochondrial DNA linking it to a very deep split in the human tree, at around 1 million years old.^[15] This would make the DNA erectus rather than heidelbergensis or other more recent splits.^[16] However, the analysis of the nuclear DNA points to a sister group relationship with the neanderthals.^[17]

See also

• List of human evolution fossils

References

Coordinates: 34°52′N 109°44′E / 34.867°N 109.733°E / 34.867; 109.733