Florisbad Skull

The Florisbad Skull is an important human fossil of the early Middle Stone Age, representing either late Homo heidelbergensis or early Homo sapiens. It was discovered in 1932 by T. F. Dreyer at the Florisbad site, Free State Province, South Africa.

Florisbad Skull
Common nameFlorisbad Skull
SpeciesHomo sapiens
or Homo helmei
or Homo heidelbergensis
Age259±35 ka
Place discoveredFlorisbad archaeological and paleontological site, South Africa
Date discovered1932
Discovered byThomas F. Dreyer, G. Venter[1]

Classification

The Florisbad Skull was classified as Homo (Africanthropus) helmei by Dreyer (1935), after the sponsor of Dreyer's expedition, R. E. Helme. The Africanthropus generic name proposed by Dreyer was taken up by Weinert (1938) to refer to early African human fossils. In a note to Dreyer's 1935 publication, C. U. Ariëns Kappers mentioned the close resemblance of the fossil to Homo sapiens fossilis (Cro-Magnon Man). M. R. Drennan (1935, 1937) emphasized resemblance to Homo neanderthalensis, proposing his classification as Homo florisbadensis (helmei). A. Galloway (1937) proposed classification as Homo sapiens, specifically noting a resemblance to modern Australoids. Commentators of the 1950s to 1970s have drawn attention to archaic African human fossils such as Saldanha and Kabwe crania (now assigned to H. heidelbergensis). Clarke (1985) compared it to Laetoli Hominid 18 and Omo 2, which are now considered early anatomically modern human (H. sapiens) fossils.

The difficulty of placing the fossil in either H. heidelbergensis or H. sapiens prompted McBrearty and Brooks (2000) to revive the designation H. helmei.[1] In 2016 Chris Stringer argued that the Florisbad Skull, along with the Jebel Irhoud and Eliye Springs specimens, belong to an archaic or "early" form of Homo sapiens.[2] The Florisbad Skull was also classified as Homo sapiens by Hublin et al. (in 2017), in part on the basis of the similar Jebel Irhoud finds from Morocco.[3][4] Scerri et al. (2018) adduce the fossil as evidence for "African multiregionalism", the view of a complex speciation of H. sapiens widely dispersed across Africa, with substantial hybridization between H. sapiens and more divergent hominins in different regions.[5] Lahr and Mounier (2019) also classify the Florisbad Skull as an example of early H. sapiens, which they suggest arose between 350,000 and 260,000 years ago from the merging of populations in East and South Africa.[6][7]

Description

The Florisbad Skull belonged to a specimen within the size range of modern humans, with a brain volume larger than modern averages, at 1,400 cm3. The skull was also found with Middle Stone Age tools.[8]

The fossil skull is a fragment; preserved are the right side of the face, most of the frontal bone, and some of the maxilla, along with portions of the roof and sidewalls. A single, upper right, third molar was also found with the adult skull.

The skull also showed extensive porotic hyperostosis as well as a large number of healed lesions, including pathological drainage or vascular tracts. There are also a couple of large puncture marks and scratch-like marks which may reflect hyena chewing.[9]

Based on enamel samples from the tooth found with the skull, the fossil has been directly dated by electron spin resonance dating to around between 259±35 ka (between 294,000 and 224,000 years old).[9]

Context
Further information: Florisbad archaeological and paleontological site

The partial cranium is part of an assemblage of mostly carnivore prey remains, caught in vertical spring vents. It shows damage by hyena chewing. The spring vents were later sealed by deposits. "Peat II" is a deposit of dark organic clay representing a Middle Stone Age land surface, showing a human occupation horizon dated 121±6 ka.[9]

The wider Florisbad site has also produced a large and diverse fauna. The assemblage including micro-vertebrates from springhares, rabbits, rodents and reptiles has informed researchers on the paleoenvironment of the interior of South Africa in the Middle Pleistocene. The large mammal component of the site suggests an open grassland with a body of water in the immediate vicinity.[10] Although many specimens are dated by comparisons of faunal assemblages, this method does not prove to have accurate chronological resolution for much of the last million years.[11]

See also

References
  1. Schwartz, Jeffrey H.; Tattersall, Ian (2005-03-11). The Human Fossil Record, Craniodental Morphology of Genus Homo (Africa and Asia). John Wiley & Sons. p. 79–81. ISBN 9780471326441..
  2. Stringer, C. (2016). "The origin and evolution of Homo sapiens". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 371 (1698): 20150237. doi:10.1098/rstb.2015.0237. PMC 4920294. PMID 27298468.
  3. Sample, Ian (7 June 2017). "Oldest Homo sapiens bones ever found shake foundations of the human story". The Guardian. Retrieved 7 June 2017.
  4. Hublin, Jean-Jacques; Ben-Ncer, Abdelouahed; Bailey, Shara E.; Freidline, Sarah E.; Neubauer, Simon; Skinner, Matthew M.; Bergmann, Inga; Le Cabec, Adeline; Benazzi, Stefano; Harvati, Katerina; Gunz, Philipp (2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF). Nature. 546 (7657): 289–292. Bibcode:2017Natur.546..289H. doi:10.1038/nature22336. PMID 28593953.
  5. "Other early H. sapiens fossils from Florisbad in South Africa (~260 ka), Omo Kibish (~195 ka) and Herto (~160 ka), both in Ethiopia, are morphologically diverse. This diversity has led some researchers to propose that fossils such as Jebel Irhoud and Florisbad actually represent a more primitive species called 'H. helmei', using the binomen given to the Florisbad partial cranium in 1935. ...However, we view H. sapiens as an evolving lineage with deep African roots, and therefore prefer to recognize such fossils as part of the diversity shown by early members of the H. sapiens clade." Scerri, EML; Thomas, MG; Manica, A; Gunz, P; Stock, JT; Stringer, C; Grove, M; Groucutt, HS; Timmermann, A; Rightmire, GP; d'Errico, F; Tryon, CA; Drake, NA; Brooks, AS; Dennell, RW; Durbin, R; Henn, BM; Lee-Thorp, J; Petraglia, MD; Thompson, JC; Scally, A; Chikhi, L (2018). "Did Our Species Evolve in Subdivided Populations across Africa, and Why Does It Matter?". Trends Ecol Evol. 33 (8): 582–594. doi:10.1016/j.tree.2018.05.005. PMC 6092560. PMID 30007846.
  6. Mounier, Aurélien; Lahr, Marta (2019). "Deciphering African late middle Pleistocene hominin diversity and the origin of our species". Nature Communications. 10 (1): 3406. Bibcode:2019NatCo..10.3406M. doi:10.1038/s41467-019-11213-w. PMC 6736881. PMID 31506422.
  7. Zimmer, Carl (10 September 2019). "Scientists Find the Skull of Humanity's Ancestor — on a Computer - By comparing fossils and CT scans, researchers say they have reconstructed the skull of the last common forebear of modern humans". The New York Times. Retrieved 10 September 2019.
  8. Rightmire, G. Philip (2009-09-22). "Middle and later Pleistocene hominins in Africa and Southwest Asia". Proceedings of the National Academy of Sciences. 106 (38): 16046–16050. Bibcode:2009PNAS..10616046R. doi:10.1073/pnas.0903930106. ISSN 0027-8424. PMC 2752549. PMID 19581595. "Homo helmei". Bradshaw Foundation. Retrieved 2015-11-18.
  9. Grün, Rainer; Brink, James S.; Spooner, Nigel A.; Taylor, Lois; Stringer, Chris B.; Franciscus, Robert G.; Murray, Andrew S. (1996-08-08). "Direct dating of Florisbad hominid". Nature. 382 (6591): 500–501. Bibcode:1996Natur.382..500G. doi:10.1038/382500a0. PMID 8700221. S2CID 4435718..
  10. Lewis, Patrick J.; Brink, James S.; Kennedy, Alicia M.; Campbell, Timothy L. (2011). "Examination of the Florisbad microvertebrates". South African Journal of Science. 107 (7/8). doi:10.4102/sajs.v107i7/8.613.
  11. Millard, A.R. (2008). "A critique of the chronometric evidence for hominid fossils: I. Africa and the Near East 500-50 ka" (PDF). J Hum Evol. 54 (6): 848–874. doi:10.1016/j.jhevol.2007.11.002. PMID 18201747.

28°46′S 26°04′E

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