Longlin 1, a partial skull

The Red Deer Cave people are a prehistoric archaic human population. Fossils dated to the Bølling-Allerød warming, between about 14,500 to c. 11,500 years ago, were found in Red Deer Cave (Maludong, Chinese: ) and Longlin Cave, Yunnan Province, in Southwest China.

The fossils exhibit a mix of archaic and modern features and are tentatively thought to represent a late survival of an archaic human species, or of a hybrid population of Denisovan hominin and modern human descent, or alternatively just "robust early modern humans, probably with affinities to modern Melanesians".^[1][2]

Evidence shows large deer were cooked in the Red Deer Cave, giving the people their name.^[3]

Discovery and dating

Mandibles

In 1979, the partial skull of a cave dweller was found in Longlin Cave in the Guangxi region of China. Additional human remains were excavated from Maludong in 1989.

In 2012, the Red Deer Cave fossils were indirectly radiocarbon dated between 14,300 and 12,600 years before present, using charcoal found in the fossil deposits. The single Longlin fossil was dated to 11,500 years before present (mean calibrated age 11,510±255 95% CI).^[4]

A partial thighbone was discovered in Maludong in 1989, along with a partial jaw, cranial bones, and teeth. The dating of the bones has led to confusion and division among researchers. The anatomy of the bones, without successful DNA testing, shows them to be archaic humans, like early Homo erectus or Homo habilis which lived around 1.5 million years ago in Africa.^[5] Researcher Darren Curnoe believes that the cave people were a new evolutionary line. This is because of the skulls are different from both modern humans and human skulls found in Africa dating back 150,000 years.^[6] From the thighbone analysis, it is believed that they roamed the same landscape as modern humans for 60,000 years.^[7]

Anatomy

In spite of their relatively recent age, the fossils exhibit archaic human features.^[8] The Red Deer Cave dwellers had distinctive features that differ from modern humans, including: flat face, broad nose, jutting jaw with no chin, large molars, prominent brows, thick skull bones, and moderate-size brain.^[1] As with other pre-modern humans, their body size was small, with an estimated mass of 50 kg (110 lb).^[9]

From the shape of the thighbone, it is believed that the Red Deer Cave People may have been knock-kneed.^[10] Curnoe's previous works showed the bones and teeth were remarkably similar to that of archaic humans.^[11] This is despite their having lived until recently, between 14,000 and 11,000 years ago.^[12] The reconstruction of the Maludong femur confirmed it was very small with the outer shell, or walls, are very thin. The areas of the wall that were of high strain, and the femur neck, are relatively long; the place of muscle attachment for the primary flexor muscle of the hip (the lesser trochanter) was robust and faced strongly backward.^[13]

Classification

Experts are reluctant to classify the Red Deer Cave people as a new species.^[1] They might represent a previously unknown archaic human lineage, or the result of mating between Denisovans and modern humans,^[3] or alternatively a thoroughly anatomically modern human population with unusual physiology.^[1] However, research shows the Red Deer Cave people appear similar to more archaic lineages such as Homo erectus or Homo habilis.^[9] Specifically, the specimen appears most similar in most of the characteristics to KNM-ER 1481,^[8] a Homo Erectus from 1.89 Mya found in Africa.^[14] Others have noted similarities to Australopithecus (taken to mean beyond Homo, ed.).^[15] Attempts to isolate ancient DNA from the fossils have not been successful.^[16]

One theory suggests that the Red Deer Cave people were early humans that settled into the region more than 100,000 years ago and became isolated.^[17] The high mountains and deep valleys are ideal in isolating species geographically, so it is possible for a species to migrate to the area and become genetically isolated over time. The environment and climate of Southwest China are unique owing to the tectonic uplift of the Qinghai-Tibetan Plateau. The Yunnan province still today has some of the greatest biodiversity in all of China.

Since as yet no DNA has been successfully extracted from the bones, the research that has been done is leading to the conclusion that the Red Deer Cave People are the result of a hybridization with modern humans. Another theory that has been stated by Maciej Henneberg, a professor at the University of Adelaide and an expert in human anatomy, is that the bone is not that of a primate at all. It may be a deer's femur that has degraded to the point it was misidentified.

See also

• Interbreeding between archaic and modern humans
• Timeline of human evolution
• Timeline of the evolutionary history of life

References

External links

• Media related to Red Deer Cave people at Wikimedia Commons
• Defining 'human' - new fossils provide more questions than answers (article by Darren Curnoe in The Conversation, March 15, 2012)
• Enigma Man: A Stone Age Mystery (Aired by ABC TV on Tuesday 24 June 2014, 8:30pm)
• Human Timeline (Interactive) - Smithsonian, National Museum of Natural History (August 2016).