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Wednesday, December 18, 2019

Homo erectus lived until very recently (~100 Kya)!


An article publised today in Nature (Rizal, Y., Westaway, K.E., Zaim, Y. et al. Last appearance of Homo erectus at Ngandong, Java, 117,000–108,000 years ago. Nature (2019) doi:10.1038/s41586-019-1863-2), reports that the remains of twelve Homo erectus discovered in the early 1930s on the banks of the Solo River in Ngandong, Java, are far younger than expected.


The scientists returned to the original site (excavated in 1931-33) and using the original notes and photographs, found an area that had been purposely left untouched, and dug there, recording the stratigraphy and dating the soil level where the skulls were found.


Their abstract reports:


" Abstract Homo erectus is the founding early hominin species of Island Southeast Asia, and reached Java (Indonesia) more than 1.5 million years ago. Twelve H. erectus calvaria (skull caps) and two tibiae (lower leg bones) were discovered from a bone bed located about 20 m above the Solo River at Ngandong (Central Java) between 1931 and 1933, and are of the youngest, most-advanced form of H. erectus. Despite the importance of the Ngandong fossils, the relationship between the fossils, terrace fill and ages have been heavily debated. Here, to resolve the age of the Ngandong evidence, we use Bayesian modelling of 52 radiometric age estimates to establish—to our knowledge—the first robust chronology at regional, valley and local scales. We used uranium-series dating of speleothems to constrain regional landscape evolution; luminescence, 40argon/39argon (40Ar/39Ar) and uranium-series dating to constrain the sequence of terrace evolution; and applied uranium-series and uranium series–electron-spin resonance (US–ESR) dating to non-human fossils to directly date our re-excavation of Ngandong. We show that at least by 500 thousand years ago (ka) the Solo River was diverted into the Kendeng Hills, and that it formed the Solo terrace sequence between 316 and 31 ka and the Ngandong terrace between about 140 and 92 ka. Non-human fossils recovered during the re-excavation of Ngandong date to between 109 and 106 ka (uranium-series minimum) and 134 and 118 ka (US–ESR), with modelled ages of 117 to 108 thousand years (kyr) for the H. erectus bone bed, which accumulated during flood conditions. These results negate the extreme ages that have been proposed for the site and solidify Ngandong as the last known occurrence of this long-lived species"


The paper also says: (bold highlight is mine)


"Furthermore, we can place Ngandong into a regional framework for Island Southeast Asia. H. erectus continuously inhabited the island, with dates on Java that start at 1.51 to 0.93 million years ago at Sangiran, then 540 to 430 ka at Trinil25 and ending with 117 to 108 ka at Ngandong. H.erectus was dispersed widely by 700 ka, as shown by archaeological evidence for hominins at Mata Menge (Flores, Indonesia) and Cagayan Valley (Luzon, Philippines). Two insular dwarf hominins are found on these outlying islands: Homo floresiensis at 100 to 60 ka and Homo luzonensis at 66.7±1 ka. Phylogenetic relationships have yet to be deter-mined for these two hominins, but they show morphological similarities with H. erectus. Sharing similar temporal ranges, Ngandong H.erectus, H.floresiensis and H. luzonensis represent three evolutionary trajectories of Homo in Island Southeast Asia, each of which ended in extinction.
Genomic evidence from modern populations in New Guinea provides estimates for the dates of the arrival of another early hominin in Island Southeast Asia. Two Denisovan lineages diverged from the Altai Denisovans, one at about 363ka and the other at about 283ka. These deep divergence dates provide evidence for the early arrival of Denisovans in Island Southeast Asia. Dispersing Homo sapiens encountered Denisovan lineages in Island Southeast Asia at about 45.7 ka and at about 29.8 ka. Additionally, a residual signal of approximately 1% archaic DNA in modern regional populations lies outside the human–Neanderthal–Denisovan clade. This may reflect a past introgression event with H.erectus and provide evidence that these Denisovans encountered a late-surviving H.erectus population
"


There are sites (Ngawi and Sambungmacan, also in Java) that have not been dated yet and may yield even more recent dates. But even 100,000 years is very recent.


The earliest evidence of Homo sapiens in Eurasia are the fossil skuls from Apidima Cave in Greece, dated at 210 Kya. By 100,000 years ago, Modern Humans were already living in Africa and very likely in the Levant (as per orthodoxy of coursee). So we coexisted with H erectus (I once posted about this -but in my post our ancestors and H. erectus mixed intimately in America).


All these sites and older ones (such as Trinil and Sangiran) are located on the Solo River where Eugene Dubois unearthed the first Homo erectus remains in 1891.



Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2020 by Austin Whittall © 

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