This is another post in my series on pre-Clovis sites in America. A bone of an extinct ground sloth, a Lestodon, found in Uruguay, close to its capital city of Montevideo was reported last year by Fariña et al. The research paper cautiously suggests that the hole in the bone of this sloth was caused by humans, 33,000 years ago.
Read the original paper: Fariña RA, Hayes E, Lemoine LA, Fullagar R, Tambusso PS, Varela L (2025) An indentation in a 33,000-year-old right calcaneus of the ground sloth Lestodon (Xenarthra, Folivora) from Uruguay and its possible human agency. Swiss Journal of Palaeontology 144: 31. https://doi.org/10.1186/s13358-025-00379-0
The hole in the right calcaneus (a bone in the paw) of a ground sloth (Lestodon armatus), was found in Uruguay, in a site by a creek (Arroyo Vizcaíno), that has been dated by radiocarbon to 33,000 cal years ago. The authors, who made a cast of the hole and sampled it "argue that it could have been created by a penetrating object with a rounded tip, possibly a bone, ivory or hardened wood tip attached to a shaft. This evidence contributes to discussions on the dates of human arrival in South America and the potential interactions with the megafauna."
The paper points out that the lesion hadn't healed, it was not caused by cancer (neoplasia). It discards an attack by a predator as there are no other lesions in the bones (why would only one tooth of the preadotr impact the prey?). The article finds damage associated with fracture caused by penetration.
"The analysis of the mark and rounded surfaces within the indentation suggests that the perforating object had a rounded cross-section without a sharpened tip. We propose it was more likely to be made of bone, ivory or (less likely) hardened wood, inserted into a shaft or sleeve that was long enough to allow sufficient energy to penetrate the thick bone and allow rotational and lateral movement to generate the double cavity visible in the CT scan. In addition, the attack angle and location suggests a very close range attack of about 1 or 2 m away, which requires a club like and a hafted point heavy enough to produce the force required to break the relatively thick flat face of the calcaneus at this short distance."
Interestingly, the authors note a link with Siberian hunting technology: "Osseous projectile technologies are representative of the Early Upper Palaeolithic to Late Upper Palaeolithic industries in central and eastern Siberia and are key to understanding initial human dispersal in the Americas." In a recent post, I mentioned this when I wrote about the Yana Rive Site in Siberia and their bone foreshafts!
This is just another pre-Clovis site, but 33,000 years old, in Southern South America. Which prompts me to ask: how many more are out there, waiting to be discovered? and also why are so few discovered? Lack of research funds in South America seems to be the main reason, because when the local researchers look for pre-Clovis evidence, they find it!
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ReplyDeleteHi Austin. Agree with you in that this calcaneous bone is a remarkable new possible evidence of human activity, that certainly adds to that already found at Arroyo del Vizcaino … Even though the anthropogenic interaction claimed by the authors will surely be viewed with skepticism (mainly due to its age, which seems irrefutable), there is no doubt that this is another piece that deserved to be published… since there seem to be clear indications (at least to me) pointing to: a) that this “wound” does not appear to have been made by the typically uniform pressure of a mammal tooth, but rather by an impulsive force; b) that it also does not appear to be a consequence of any infectious or abnormal process within the bone… and furthermore, c) that it would not be a “recent” event, since this type of bone modification (in which there is a clear perforation and also sunken cortical parts) strongly suggests that the bone tissue retained its elastic properties until that moment (that is; it was not fossilized)… and thus, such modification would be contemporaneous with the bone's dating… (Ref*).
Not long ago, during a cultural event related with Paleantology, I had the opportunity to personally meet Richard Fariña (by the way, not only a cool researcher but also an excellent person), and we were able to exchange a few words about the progress of his research at this site. He told me that he and his team are actively continuing to try to identify more signs of human intervention within the enormous sample of extinct fauna bones that this important site has yielded… within which, according to him, there are “countless interesting pieces” that are being (or will be) studied, employing (as with this calcaneus) the most advanced diagnostic tools and methods…
The main problem that Fariña and his collaborators have had to deal with all these years, is that Arroyo del Vizcaino was never recognized as a “well-defined archaeological site,” perhaps due to its scarcity of convincing lithic material and/or other forms of evidence, even though possessing, in my opinion, concrete and unequivocal evidence that “someone was” in that place around 30,000 years ago… since; 1) there are at least two pieces; a rib and a clavicle from Lestodon, whose marks of human manipulation seem to be extremely difficult to be refuted or misinterpreted, and 2) these bones have been consistently dated to those ages using C14 on collagen… In other words, Fariña has undoubtedly a good point. And he is well aware of this, although he is currently very cautious in his statements…
Let's hope that Arroyo del Vizcaino, already a paleontological site of superlative importance, can finally obtain the additional recognition it is seeking, and which it deserves…that of being considered as yet another archaeological site that, even being still controversial for the orthodoxy, seriously proposes an earlier peopling of South America…
Another amazing post…!!
Best regards.
Marcelo
Ref*: There is no way to achieve a modification with this morphology in a fossilized bone by impact/bite, since it would simply shatter…
Thank you Marcelo.
DeleteThe early peopling of America may have some implications on the dates for the peopling of Beringia, and NE Asia. Pushing back the entry dates into America will surely have to demand a review of what we now know about the populations living in Eastern Asia.
Exciting times await us all!