Tuesday, 15 August 2017

Was Homo erectus the first human in the Americas 130,000BP?

I have covered the publication of a paper detailing the convincing evidence of man in the Americas, specifically in Southern California at 130,000BP here and here.

Holen et al. (2017) discuss the candidate species in some detail, and in their supplementary information come to the conclusion, that these species include:

1. Homo erectus
2. Homo neanderthalensis
3. Homo sp. “Denisovans”
4. “Archaic Homo sapiens”

Taking each species separately let us look at which may be the most likely candidate.

1. Homo erectus

First we should get the ‘Which Homo erectus?’ out of the way. By that I mean that some scientists, particularly Chinese scientists have suggested that “Homo erectus is a species confined to Asia. Specialized characters displayed by the Indonesian and Chinese skulls are said to be absent in material from eastern Africa, and individuals from Koobi Fora and Nariokotome are now referred by some workers to H. ergaster.” See Rightmire (1998).
Rightmire (1998), based on comparisons of facial morphology of African and Asian examples of Homo erectus, rejected this claim. From his abstract: “Much or all of the variation in facial form can be attributed to sex dimorphism and/or local differentiation of populations within the Asian and African geographic regions. Metric differences among the fossils are comparable to those documented in a subset of recent H. sapiens, and there is no evidence that the Pleistocene specimens show greater dispersion than expected within a single species. This finding is generally in keeping with observations made on other parts of the cranium, lower jaw, and teeth. All of the hominids can be placed in H. erectus. Although its phylogenetic origins remain obscure, this lineage must be rooted in Africa. The species flourished for a long time. At several sites in China, H. erectus is known from deposits of the later Middle Pleistocene, while at Ngandong in Indonesia, archaic people may have survived even into the Late Pleistocene (Swisher et al. [1996]). The Ngandong fossils may record the last appearance of the lineage.

Having dealt with that, what specimens of Homo erectus have been discovered, in Asia, and what dates are they? Could Homo erectus possibly have been the hominid that made it to California 130,000 years ago?

The earliest Homo erectus fossils discovered are from Africa (KMN ER3733 East Lake Turkana) and the Caucasus (Georgia – Dmanisi) date to ca. 1.8-1.9 Mya. Given that all early hominid species so far discovered are from Africa, it seems logical to assume that Homo erectus evolved there and migrated East.

A few examples of Homo erectus from a timeframe which would fit with the peopling of the Americas by this hominid, from Asia and China are shown on the map below. A brief summary of each site is given further down.

However, a more detailed map, showing most known Homo erectus sites in east Asia,  is given below. Click on each location for a brief biography.



Here are the details for each Homo erectus site given on the first map above:

Specimen: Ngandong 7 (Solo 6)
Location: Solo River, Central Java, Indonesia

Age: Indriati et al., (2011), reported new 40Ar/39Ar, ESR and U-series dates for Ngandong. They argue that the different dating methods indicate an age in the range of 546-612 ka, placing these three sites in the Middle Pleistocene and significantly older than previous estimates. However, they caution that the ESR/U-series date that complies with all modelling criteria is ~143 ka.


Ngandong 7 from Weidenreich, (1951). Note the straight, square brow ridges.


Another view of the same specimen from Athena Review (2004).


Specimen: Zhoukoudian composite skull cast from the Smithsonian.
Location: Zhoukoudian Cave
Age: 770,000 ka, Shen et al. (2009), Smithsonian (2016) 780,000 – 400,000 ka.


Zhoukoudian Homo erectus from the Smithsonian (2016). Original caption reads: This composite skull combines several skulls from the same site, first named Sinanthropus pekingensis but later attributed to Homo erectus. The original fossils vanished while being shipped to the United States for safety during World War II, but scientists still have high-quality casts and descriptions to work with.

An interesting facial reconstruction can be seen in this photo by Pillard (2007).


I have been unable to identify the museum in which the picture was taken, however the caption card reads: Cast of skull fragments found at Choucoutien.

Specimen: Homo erectus molars
Location: Tham Khuyen Cave, Vietnam
Age: 745,000 ka (or perhaps as late as 140-80 kyr ago in the case of the nearby Hang Hum cave).
These teeth, and indeed, the occurrence of Homo erectus in Vietnam have were debated for a decade until Ciochon et al. (1996), definitively identified them as belonging to the above hominid and not for example, Gigantopithecus blacki.

The teeth in question, adapted from Ciochon et al. (1996). Original caption reads:
FIG. 2. ..Homo erectus molars (right) from Tham Khuyen.
TK 65/105 (top right) left upper M2 (MD = 12.0, BL = 12.7), TK 65/50 (bottom right) left upper M1 (MD = 11.7, BL = 12.9). Scale bar is in cm. Other hominid teeth identified from Tham Khuyen include TK 65/53, a right upper M1 (MD = 12.1, BL = 13.3), TK 65/167 left upper C (MD = 9.9, LL = 9.8), and TK 65/8, a left upper deciduous Ml (MD = 9.9, BL = 10.8).

Additionally, another Vietnamese site, within a couple of hundred kilometres of the Tham Khuyen, has yielded Homo erectus teeth, this time of a relatively recent date, according to Schwartz and colleagues (1995): “The cave of Hang Hum has also yielded three teeth.. These teeth were initially identified as Homo sapiens, but their large size places them outside the range of our own species. The two lower molars compare most closely in size and morphology with those of Homo erectus from Zhoukoudian. The third tooth is too worn to permit similar comparison. If the lower molars are indeed those of Homo erectus, this would suggest a remarkably late survival of this species in Vietnam.” Dated approximately 140,000BP.

Is there any evidence that Homo erectus was in America 130,000BP?
Many archaeologists and bloggers make assertions that it is impossible that man arrived in the Americas before ca. 20Kya. The main piece of evidence they cite is the lack of human skeletal remains. This is a fair point. However, it depends where and how deeply you dig.
A number of archaeologists have let their curiosity get the better of them and dug far deeper than the ‘20,000BP is the limit of human occupation in the Americas’ horizon. What did they find? Artifacts.. indisputably human-made artifacts!
A few examples of the evidence are:

Monde Verde, Chile excavated by Tom Dillehay dated to 39,000BP [see here and here]

Meadowcroft Rockshelter, Pennsylvania by Adovasio dated 33,000BP [see here]

Ground Sloth Kill site reported by Farima et al. [see here]

In addition, some other sites, which I haven’t covered yet, spring immediately to mind, for example:
Topper (Goodyear)
Pendejo Cave (MacNeish)
And the quite a few others such as those in the table in a previous post I wrote in February 2016 [see here]

The earlier sites from the above could be attributed to Homo erectus or their descendants in the Americas but where are the bones to prove it?

Well there is actually, a number of specimens, one of which, I covered here.

Since that post I have come across some additional evidence from a paper published by Irish et al. (2000). The brief paper states:
The likelihood of a late-Pleistocene human presence in Jalisco, Mexico, is supported by culturally modified faunal bones, diagnostic lithics, and mineralized human bones; this report concerns the latter, which were analyzed by Irish, using standard osteological procedures (Bass 1981; Brothwell 1981; Ortner and Putschar 1985; Shipman et al. 1986; Ubelaker 1989; White 1991). All materials were recovered 50 km southeast of Guadalajara, in the Lake Chapala and Zacoalco Playa basins.

            The human remains are thought to be of late-Pleistocene age based on faunal correlation. Many have been in Solórzano’s possession for some time; others were recently collected. Like associated fauna, all are mineralized, dark in color, and fragmentary. We have a focus on their origins and will work to establish exact field proveniences in May 2000.

            The Chapala bones (n = 10) have a MNI of three, based on two left superciliary arches (brow ridges) and a deciduous incisor. The super border of each brow is blunt, implying the sex was male in both cases. However, size variations of other fragments suggest males and females are represented. The deciduous incisor is from a three-year-old; the rest represent young adults.

            One Chapala superciliary arch deserves specific mention due to its large size. Studies by Solórzano show the bone resembles that in archaic Homo sapiens at Arago, France. In an unpublished 1990 report, Texas A&M osteologists suggest the brow’s thickness and robustness are comparable to those of  KNM-ER 3733 (African Homo erectus). Our measurements show the central torus thickness is 13.3, compared with 8.5 mm for KNM-ER 3733; the lateral torus thickness is 11.5 versus 9.0 mm (Rightmire 1998). Thus for the sake of comparison, the brow is more like that of Zhoukoudian Skull XI (Asian Homo erectus), with a central torus thickness of 13.2 +/- mm; lateral torus thickness was not measured (Rightmire 1998). Modern brows are too diminutive to allow these measurements. The brow also shows pneumatization (air pockets) along its length.

            However, to reiterate the findings of the Texas A&M workers, these comparisons do not imply that pre-Homo sapiens were in the Americas.    No phylogenetic or age implications are intended. Instead, the comparisons demonstrate the size relative to most New World specimens, although brows on the Lagoa Santa skull (Bryan 1978) and on recent Tierra del Fuego and Patagonia crania (Lahr 1995; C.L. Brace pers. comm. 1998) appear comparable.

            Twenty-one fragments from Zacoalco also have a MNI of three, based on duplicate mandible and parietal fragments. Sex determination is difficult, but size variation suggest both males and females. Concerning age, an unerupted third molar crypt indicates a 12- to 16-year-old. The remainder were adults or older adults, based on cranial suture closure, a fully formed third molar socket, and Pacchionian depressions on an inner parietal surface (see Ortner and Putschar 1985).

            A Zacoalco maxilla fragment, with sockets for the canine and premolars, also deserves mention due to its size. It is much thicker and more robust than comparative specimens from other prehistoric Native American males. Like the Chapala brow, the fragment could be lost in a collection of archaic Homo sapiens maxillae. However, again, no phylogentic inferences are intended. Instead, the robust Chapala and Zacoalco remains may be suggestive of region-specific variation in late-Pleistocene central Mexico, as noted elsewhere (Pompa 1987).

            Lastly, despite the fact that the remains are mineralized and recovered with Pleistocene-age fauna, we are continuing an attempt to obtain a chronometric date. Radiocarbon dating of the remains is difficult due to mineralization. However, a Zacoalco molar was thought to contain remnant organics for AMS dating. With permission from the Museo Regional de Guadalajara, the tooth was sent to a U.S. lab that previously dated a Chapala swamp deer (Blastoceros spp.) incisor at 18,200 yr B.P. Unfortunately, the human protein was more heavily mineralized; the amount of carbon after combustion was too small to provide a reliable date. Thus, we must locate additional remains. Still, a 13C value of -24 was obtained, implying that the tooth came from a non-agriculturalist; this value exceeds that from known Paleoindian fossils (e.g., Kennewick).

            In sum, these cursory descriptions are presented for the purpose of initiating comparisons with other New World Pleistocene-age remains. A future objective is to delineate the Jalisco finds in a broader spatial and temporal context. However, in-depth regional and extra-regional comparisons must await additional data collection. Although our research team received a major setback by the death of Jack Lobdell, continuing work in the project area appears promising.

Although I cannot identify the source I additionally I came across the following picture from Charlie Hatchett (2010):

Conclusion
Much lithic and modified bone evidence has been uncovered in the Americas, apart from that, from the CM site.
Human bones of uncertain taxonomic affinity, have also been found in the Americas, which could, plausibly be those of Homo erectus.
Much of this evidence has been contested on spurious grounds (I will write an entire post on that later) or completely ignored.
As shown by the specimens illustrated and the additional one detailed on the Google map at the link further up this post, Homo erectus was in Asia for at least a million and could easily have crossed the Beringian Land Bridge. That these land bridges existed on numerous occasions in that timeframe is shown in my post here.

Therefore from the volume of evidence listed above, it is more than possible that Homo erectus was indeed the species of human responsible for modifying the Mastodon bones found in southern California 30 years ago and reported by Holen et al. (2017) and thus had peopled the Americas by 130,000BP.


References
Athena Review, Anon. 2004. Athena Review, Vol. 4, No.1: Homo erectus Introduction: The long journey of an ancient human ancestor. [ONLINE] Available at: http://www.athenapub.com/13intro-he.htm. [Accessed 20 June 2017].

Ciochon, R, et al., 1996. Dated co-occurrence of Homo erectus and Gigantopithecus from Tham Khuyen Cave, Vietnam. Proceedings of the National Academy of Science. USA, Vol. 93, April 1996, 3016-3020.
PDF download available from: http://www.pnas.org/content/93/7/3016.long

Hatchett, C. 2010. Paleo Planet, Archaeology/Anthropology Forum, The Tail Wagging the Dog. [ONLINE] Available at: http://paleoplanet69529.yuku.com/topic/33439/The-Tail-Wagging-the-Dog#.WZJTZVV97IV. [Accessed 15 August 2017].

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

Indriati, E, et al. 2011. The Age of the 20 Meter Solo River Terrace, Java, Indonesia and the Survival of Homo erectus in Asia. PLoS ONE, [Online]. 6(6): e21562. doi:10.1371/journal.pone.0021562, 1-10. Available at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0021562 
[Accessed 19 June 2017].

Irish, J.D., Lobdell, J.E., Davis, S.D. and Solórzano Barreto, F.A., 2000. Prehistoric human skeletal remains from Jalisco, Mexico. Current Research in the Pleistocene17, pp.95-97.

Pillard, S. 2007. Homo erectus. [ONLINE] Available at: http://zipcodezoo.com/index.php/File:Homo_erectus_17.jpg. [Accessed 21 June 2017

Rightmire, G.P. (1998) Evidence from facial morphology for similarity of Asian and African representatives of Homo erectus. Am J Phys Anthropol.106(1):61-85.


Schwartz, J. et al. 1995. A review of the Pleistocene hominoid Fauna of the socialist Republic of Vietnam (excluding hylobatidae) Anthropological papers of The American museum of natural history, Number 76 New York: 1995.

Schwartz J. H. and I. Tattersall. 2003. The Human Fossil Record: Craniodental Morphology of Genus Homo (Africa and Asia) v. 2 Wiley-Blackwell; 2003 p284-293

Shen, G., et al, 2009. Age of Zhoukoudian Homo erectus determined with 26Al/10Be burial dating. Nature, 458 (12 March 2009), 198-200.

Smithsonian National Museum of Natural History. 2016. 
What does it mean to be human? Zhoukoudian. [ONLINE]

Swisher III, C.C., Rink, W.J., Anton, S.C. and Schwarcz, H.P., 1996. Latest homo erectus of Java: Potential contemporaneity with homo sapiens in Southeast Asia. Science, 274(5294), p.1870.

Weidenreich, F. (1951) Morphology of Solo Man. Anthropological Papers of the American Museum of Natural History, Vol. 43: Part 3. New York.

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