Which species of humans were in southern California 130,000 years ago?

Ever since the Holen (2017) paper, that I covered here I have wondered which species of humans could possibly have migrated to America during this era. Yes, who were the humans that left the modified bones, teeth and cobbles at the Cerutti Mastodon (CM) site? In their Supplementary information, section 9. “Asian origins of early humans on the west coast of North America” Holen et al. engage in some discussion on the matter (from their Supplementary Information, Section 9. Asian origins of early humans on the west coast of North America):

“Hominins in Eurasia during MIS 5 include Homo sapiens, Homo neanderthalensis, Homo sp. (Denisova), Homo floresiensis and Homo erectus^{80, 81}. These taxa, except Homo floresiensis, could have dispersed into northeastern Asia as temperatures increased at the end of MIS 6 and during the Last Interglacial MIS 5⁸². Plausible dispersal routes for hominins to arrive on the west coast of North America at the end of MIS 6 include a land route across Beringia prior to 135 ka⁸³ and a coastal water route along the coasts of Asia, Beringia and North America…

The continuous presence of hominins beginning ~300 ka in southern Siberia at the end of the Lower Paleolithic, although many of the sites are not well-dated⁸⁴, provides a potential source of populations that could disperse eastward. By adapting to conditions in southern Siberia, hominins could have extended their range further northeast to cross Beringia during interglacial intervals. The southern edge of the Beringian land bridge at its maximum extent is estimated to have been close to 63° N, about 200 km further north than the Diring Yuriakh site situated at 60° N in Siberia. The best age estimate for the lower level of the site containing stone tools is based upon TL dates of 267-366 ka⁸⁵. However, the geoarchaeological position and age (especially of the oldest stone artefacts) have been questioned⁸⁶. It is noteworthy that fossil remains of a cold-adapted female hominin, possibly an archaic Homo sapiens, have been discovered in Manchuria, China (40° 34ʹ N). Animal teeth at the site were dated to ~ 260 ka by electron-spin resonance and uranium series dating⁸⁷. It is not yet known how far north these cold-adapted hominins dispersed, but they may be responsible for archaeological sites like Diring Yuriakh and other Early Paleolithic sites in southern Siberia.

At Denisova Cave (51.4° N) in southcentral Siberia, Homo neanderthalensis is first evidenced by the appearance of Middle Paleolithic stone tools in Stratum 22 with bracketing radio thermoluminescence (RTL) ages of 282 ± 56 and 171 ± 43 ka⁸⁸. Biostratigraphic and paleomagnetic data (Blake polarity episode) correlate more recent Denisova Cave Middle Paleolithic stone tool industries with MIS 586. Thus, there are several possible hominin candidates (late Homo erectus, Neanderthals or archaic Homo sapiens) resident in eastern Asia that could have entered North America via Beringia and dispersed to the west coast of North America at 130 ka. Another possibility is that the little-known Denisovans, related most closely to Neanderthals⁸⁹, and known only from DNA studies at Denisova Cave, were the first hominins to reach North America.

The authors then examine the evidence for sea-faring in ancient hominids and the possibility that the Skoglund (2015) “population Y” were the humans that were in California 130,000 years ago and conclude:

“The CM site currently is the only locality in North America that supports such an early hominin dispersal. This speculative discussion poses the challenge to initiate archaeological research in MIS 5e and MIS 6-age geological deposits in North America.”

From the whole section, some of which I have not quoted, the, authors have therefore established:

1. The climate in California 130,000 years ago was wetter and milder in comparison to other eras of the Pleistocene, by reference to the relevant literature.  For example, the wider distribution of mammals, including mastodon and sloth above the arctic circle and at higher altitudes in the Rocky Mountains and as witnessed by fossils found at the CM site such as a capybara (Hydrochoerus) tooth, far north of its usual range.

2. Food was therefore, plentiful for any incoming human migrants from Beringia to the Panamanian isthmus and beyond during the timeframe in question (MIS5e).

3. The humans could be candidates: “Hominins in Eurasia during MIS 5 include Homo sapiens, Homo neanderthalensis, Homo sp. (Denisova), Homo floresiensis and Homo erectus80, 81. These taxa, except Homo floresiensis, could have dispersed into northeastern Asia as temperatures increased at the end of MIS 6 and during the Last Interglacial MIS 5.”

4. Although they discount archaic modern humans (AMH), given the recent findings of much older, ca. 300,000BP archaic modern humans from Jebel Irhoud (Richter, et al. 2017) and the 120,000BP Chinese teeth from Fuyan Cave in Daoxian, province (Lui et al. 2015) there seems at least a possibility that Homo sapiens were the species that came to America 130,000 years ago.

The candidate species therefore are:

• Homo erectus

• Homo neanderthalensis

• Homo sp. “Denisovans”

•  Archaic Homo sapiens

Here are a few mug shots:

Clockwise from top left:

Homo erectus from Wikipedia (2017). Original caption reads: Dmanisi skull 3, Fossils skull D2700 and D2735 jaw, two of several found in Dmanisi in the Georgian Caucasus.

Homo neanderthalensis from North Carolina School of Science and Mathematics (2017). Original caption reads: Hominid Skull - Homo neanderthalensis La Chapelle-aux-Saints 1 "The Old Man". Estimated Age: 60,000 years. Location: La Chapelle-aux-Saints, France

Homo sp. “Denisovans” from Discover magazine (2016). Original caption reads: A molar that belonged to an ancient Denisovan. Max Planck Institute for Evolutionary Anthropology

Archaic Homo sapiens from Peter Brown Palaeoanthropology (2017). Original caption reads: Dali is reasonably complete and well preserved, with damage restricted to postdepositional crushing and displacement of the palate and left maxilla. A large section of the right parietal is missing, as are the maxillary teeth and left zygomatic arch. Wu (1981, 1989) found that most of the cranial dimensions and morphological features of Dali were intermediate between Homo erectus and H. sapiens, with Dali assigned to archaic H. sapiens.

In future posts, I will consider each of the above species of human and what the possibility/evidence of them reaching the Americas 130,000 years ago is.

References

Discover magazine (2016), retrieved from:

http://discovermagazine.com/2016/dec/meet-the-denisovans

Holen, S. R., et. al. (2017) A 130,000-year-old archaeological site in southern California, USA Nature 544, 479–483 doi:10.1038/nature22065

Can be accessed here: http://www.nature.com/nature/journal/v544/n7651/full/nature22065.html

And the Supplementary information can be downloaded from here:

https://www.nature.com/article-assets/npg/nature/journal/v544/n7651/extref/nature22065-s1.pdf

Liu, Wu, et al. "The earliest unequivocally modern humans in southern China." Nature 526.7575 (2015): 696-699.

North Carolina School of Science and Mathematics (2017), retrieved from:

http://www.dlt.ncssm.edu/tiger/360views/Hominid_Skull-H_neanderthalensis_LaChapelleA_1200x900/index.html

Peter Brown Palaeoanthropology (2017). Retrieved from:

http://www.peterbrown-palaeoanthropology.net/dali.html

Richter, Daniel, et al. "The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age." Nature 546.7657 (2017): 293-296.

Skoglund, P. et al. Genetic evidence for two founding populations of the Americas. Nature 525, 104-108 (2015).