D2700

Dmanisi skull 3
Catalog number D2700
Common name Dmanisi skull 3
Species Homo georgicus
Age 1.8 million years
Place discovered Dmanisi in Georgia
Date discovered 2001
Discovered by Abesalom Vekua and David Lordkipanidze

D2700 is the catalogue number of a fossilized Homo georgicus skull which was discovered in 2001 in Dmanisi, Georgia. This is an almost complete skull and is in an exceptionally good condition.[1]

Since the publication of the 5th skull of Dmanisi in 2013, all of the 5 Dmanisi skulls (skull 3 included) are in the middle of a major paleontological controversy : many hominids fossils thought to be different species, such as Homo ergaster or Homo habilis may not have been separate species at all. Most of human ancestors were possibly one evolving lineage.[2] To learn more about this controversy, read the article on Dmanisi skull 5.

Discovery

D2700 and D2735 were found in 2001, just a decade later after the first discovery of an early hominid mandible D211 at Dmanisi on September 24, 1991. In 1999 partial crania, D2280 and D2282, were discovered. Cranium D2282 is likely the accompanying skull to mandible D211 and was likely to be the remains of a young adult around 18–20 years old. Skull D2280 is inferred to have been an adult around 25–30 years old at the time of death.[3] Moreover, in 2005, a new complete skull cranium was found: D4500. The cranium is inferred to be an adult skull and is more commonly known as “skull 5.” D4500’s features are very rare compared to early Homo in that it had a small braincase yet an unusually large prognathic face.[4] “Skull 5” has an accompanying mandible, D2600, which was found in 2000.

In 1999 two other skulls had been found at the same site – D2280 and D2282. D2280 was a near-complete brain-case with 780 cc brain-size. D2282 was a cranium and it included many of the facial and upper jaw bones. Its brain size was about 650 cc.[1] In 1991 and 2000 two more lower jaws D211 and D2600 were discovered from the same site.

Observations

Dmanisi skull 3, Fossils skull D2700 and D2735 jaw, two of several found in Dmanisi in the Georgian Caucasus

The skull was found in an exceptionally good condition including a lower jaw (D2735) found about a meter away which is considered to be of the same person. D2700 is smaller than D2282. The fossil is about 1.8 million years old and its brain size is estimated at 600 cc. There are many characteristics in which it resembles H. ergaster (or erectus) and also a number that resembles the ER1813. Vekua et al., concluded in their 2002 paper–[5]

In overall shape, D2700 is similar to D2280 and D2282, and D2735 resembles D211. Despite certain differences among these Dmanisi individuals, we do not see sufficient grounds for assigning them to more than one hominid taxon. We view the new specimen as a member of the same population as the other fossils, and we here assign the new skull provisionally to Homo erectus.

All Dmanisi hominid remains were suggested to have been buried quickly after death. D2700 was found with four upper teeth, while D2735 contained eight teeth. As both fossil hominid remains are jointed, it is found that they ultimately fit one another. D2700’s narrow nasal bones were found inferiorly broken from the orbital margins. Because of the cranium’s upper molars being partially erupted, D2700 is believed to have been the skull of a 13-15 year old individual.[3] It is considered that the skull was of a teenager.[6]

Species Controversy

Detailed view of Dmanisi skull 3

Categorical differences such as the mandibular and dental features that the crania from Dmanisi seemed to display taxic diversity, rather than all five deriving from the same H. erectus lineage.[7] D2700 has a rather small braincase and is unusual of that of H. erectus characteristics. For this reason, D2700, along with Dmanisi fossil remains, are ascribed to the new species, "H. georgicus". H. georgicus are relatively smaller in size that "H. erectus" [3]

Gender Controversy

Given that D2700 is smaller in size than skulls D2280 and D2282, it has been suggested that sexual dimorphism may be at play and D2700 was the skull of a female [3] Theories that suggest this notion are the more slender-like features this cranium has compared to its more robust featured counterparts. However, there is uncertainty in considering a gender by the huge upper canines D2700 was found with and large crowns.[8]

The 5 Dmanisi skull are named:

See also

References

  1. ↑ 1.0 1.1 "D2700". talkorigins.org. Retrieved 15 October 2012.
  2. ↑ Skull suggests three early human species were one : Nature News & Comment
  3. ↑ 3.0 3.1 3.2 3.3 Lumley (2006). "Human Remains from the Upper Pliocene- Early Pleistocene Dmanisi site, Georgia (1991-2000). Part 1 Fossil Skulls D2280, D2282, and D2700". L'Anthropologie 110 (1): 1–110.
  4. ↑ Lordkipanidze, D.; Ponce de Leon, M. S.; Margvelashvili, A.; Rak, Y.; Rightmire, G. P.; Vekua, A.; Zollikofer, C. P. E. (17 October 2013). "A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo". Science 342 (6156): 326–331. doi:10.1126/science.1238484.
  5. ↑ "Dmanisi’s Paleoanthropological Importance". Anthropology.net. Retrieved 15 October 2012.
  6. ↑ "Dmanisi skull". anthropology.net. Retrieved 15 October 2012.
  7. ↑ Schwartz, J. H.; Tattersall, I.; Chi, Z. (24 April 2014). "Comment on "A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo"". Science 344 (6182): 360–360. doi:10.1126/science.1250056.
  8. ↑ Vekua, A. (5 July 2002). "A New Skull of Early Homo from Dmanisi, Georgia". Science 297 (5578): 85–89. doi:10.1126/science.1072953. PMID 12098694.