A Philippine group of people have the highest level of Denisovan ancestry

Another recent publication that caught my eye refers to Denisovans (Philippine Ayta possess the highest level of Denisovan ancestry in the world, by Maximilian Larena et al, August 12, 2021. Cuurent Biology. DOI:https://doi.org/10.1016/j.cub.2021.07.022).

The paper tells us:

"Highlights:... Ayta Magbukon display ∼30%–40% greater Denisovan ancestry than Australopapuans. The model is explained by a distinct admixture event into Negritos from Denisovans. Prior to modern humans, Islander Denisovans may have been present in the Philippines
Summary
... We show that Ayta Magbukon possess the highest level of Denisovan ancestry in the world—∼30%–40% greater than that of Australians and Papuans—consistent with an independent admixture event into Negritos from Denisovans. Together with the recently described Homo luzonensis, we suggest that there were multiple archaic species that inhabited the Philippines prior to the arrival of modern humans and that these archaic groups may have been genetically related. Altogether, our findings unveil a complex intertwined history of modern and archaic humans in the Asia-Pacific region, where distinct Islander Denisovan populations differentially admixed with incoming Australasians across multiple locations and at various points in time."

The paper argues that "The significantly higher level of Denisovan ancestry in Ayta Magbukon relative to Papuans highlights the possibility of an independent Denisovan introgression event in the Philippines among Negritos that is different from the Denisovan introgression event into the ancestors of Australopapuans. This observation is consistent with recent studies suggesting multiple pulses of Denisovan introgression into humans, that Denisovans were probably widespread throughout ISEA, and that Ayta Negritos were likely to have experienced a second Denisovan introgression event."

Furthermore, the Denisovans had split into different groups in the region and admixed separately with Papuans and Aytas: "our simulations provide support for the presence of two separate Denisovan lineages that independently introgressed into the ancestors of Ayta Negritos and Papuans, likely occurring around the same time after the Negrito-Papuan divergence 53 kya (95% CI: 41–64 kya). Upon entry of the first modern human migrants into Sunda and Sahul (ancestors of Negritos and Australopapuans), these ancestral Australasian groups likely experienced admixture with deeply divergent Denisovan-related populations scattered all throughout the ISEA and the Oceania region."

It also has an interesting suggestion regarding the different archaic hominins in the region (but it does not mention H. erectus): "Additionally, the physical evidence for a previously undescribed hominin in Luzon 67 kya, where present-day Negritos reside, combined with the genetic evidence presented here, raises the possibility that the suggested Homo luzonensis and Denisovans were likely genetically related, either as distinct forms or possibly belonging to the same group residing on the islands. Furthermore, it is not entirely impossible that the recently identified new species of archaic hominins in the Indonesian island of Flores, the Homo floresiensis,38 may also be related to Denisovans. Hence, the presence of multiple archaic human remains in the region, together with the genomic evidence presented here and elsewhere, raises the possibility that the Denisovans comprised deeply structured populations with considerable genetic and phenotypic diversity,"

Let's hope that we can soon identify the links between Denisovans and these other hominins.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2021 by Austin Whittall © 

H. luzonensis and H. floresiensis possible link to Denisovans

Just a brief post to share a paper published yesterday (Introgression, hominin dispersal and megafaunal survival in Late Pleistocene Island Southeast Asia Joao C Teixeira, Guy S Jacobs, Chris Stringer, Jonathan Tuke, Georgi Hudjashov, Gludhug A Purnomo, Herawati Sudoyo, Murray P Cox, Ray Tobler, Chris SM Turney, Alan Cooper, Kristofer M Helgen bioRxiv 2020.07.24.219048; doi: https://doi.org/10.1101/2020.07.24.219048).

The authors were looking into the "super-archaic" hominins that were discovered in the Island Southeast Asia (ISEA) region: Homo luzonensis and H. floresiensis, which were contemporary to anatomically modern humans (AMH). As modern populations in the region have a high level of Denisovan introgression they wanted to find out if there was also a signal of introgression from the super-archaics in the region.

Their analysis failed to detect super-archaic admixture but they reached an interesting conclusion:

"An alternative explanation is that H. luzonensis and H. floresiensis belong to a hominin clade that is considerably less divergent from AMH than is currently accepted, possibly being the latesurviving descendants of an earlier radiation of a Denisovan-like lineage across ISEA.
This would imply that hominin occupation of Flores (1.2Ma) and the Philippines (700ka) was not continuous and that the ubiquitous Denisovan ancestry across ISEA, which includes signals of admixture from a Denisovan population that diverged from the Altai Denisovans ~280ka, results from AMH admixture with one or both of these groups.
Indeed, the patterning of Denisovan ancestry across ISEA is consistent with separate Denisovan introgression events in the Philippines and, potentially, in Flores. Despite the complete lack of support for this scenario from current morphological interpretations, it is possible that pronounced dwarfism and prolonged periods of endemic island evolution for H. floresiensis and H. luzonensis complicate morphological assessments and phylogenetic placement of these groups.
While it would simplify the search for ‘southern Denisovans’ if they could be linked with the dwarfed hominins of Flores and Luzon, existing archaeological and morphological data and Flores as a more likely location for the sources of Denisovan-like DNA."

Below a map of the sites where Denisovan, Flores and Luzon hominins' remains were found:

Could the Denisovans be a link to the Homo erectus population of Asia? Current research links them to Neandertals in western Eurasia.

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

The most recent information on Admixture with archaic hominins

A paper (Using hominin introgression to trace modern human dispersals, Joao C. Teixeira and Alan Cooper, PNAS first published July 12, 2019 https://doi.org/10.1073/pnas.1904824116 - behind a pay wall), reports admixture with several groups of hominins other than Denisovans and Neanderthals during the dispersal of modern humans around the globe.

The abstract says the following:

"bstract The dispersal of anatomically modern human populations out of Africa and across much of the rest of the world around 55 to 50 thousand years before present (ka) is recorded genetically by the multiple hominin groups they met and interbred with along the way, including the Neandertals and Denisovans. The signatures of these introgression events remain preserved in the genomes of modern-day populations, and provide a powerful record of the sequence and timing of these early migrations, with Asia proving a particularly complex area. At least 3 different hominin groups appear to have been involved in Asia, of which only the Denisovans are currently known. Several interbreeding events are inferred to have taken place east of Wallace’s Line, consistent with archaeological evidence of widespread and early hominin presence in the area. However, archaeological and fossil evidence indicates archaic hominins had not spread as far as the Sahul continent (New Guinea, Australia, and Tasmania), where recent genetic evidence remains enigmatic."

Apparently the following admixture events took place between our unchaste ancestors and the other humans they met during their travels:

1. Neanderthals: in the Middle East (?) 50 - 55 kya
2. Unknown human similar to Neanderthals and Denisovans. More recent than 50 kya. In Northern India. Modern Punjabi and Bengal populations have some DNA from this admixture event.
3. Humans that headed into Central and Eastern Asia: Admixture with Denisovans.
4. Humans heading south into the Malaysian Peninsula: mixed with a relative of the Denisovans which had split from those living in Central Asia some 280 kya. This introgression took place in Malaysia or Borneo.
5. This group split: those heading into the Philippines mixed with yet another group of Denisovans and the hunter-gatherers living there nowadays carry this genetic imprint.
6. The group heading south towards Australia met some humans which were not Homo erectus, or Neaderthal or Denisovan, they were not the Flores "Hobbit" either. The genetic signals of this archaic group has been found int he short-statured people living on Flores nowadays.

Nobody seems to have admixed with the other known species of that region: the Homo luzonensis (from the Philippines) and the Flores Island hobbits.

The following images are from this paper:

 

 

These unknown hominins are indeed a very interesting find! We will have to await for further studies to learn more about them.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2019 by Austin Whittall © 

New species of Homo in Asia!

A paper published in Nature (A new species of Homo from the Late Pleistocene of the Philippines Florent Detroi et al., Naturevolume 568, pages181–186, 2019) today, tells us the following:

A hominin third metatarsal discovered in 2007 in Callao Cave (Northern Luzon, the Philippines) and dated to 67 thousand years ago provided the earliest direct evidence of a human presence in the Philippines. Analysis of this foot bone suggested that it belonged to the genus Homo, but to which species was unclear. Here we report the discovery of twelve additional hominin elements that represent at least three individuals that were found in the same stratigraphic layer of Callao Cave as the previously discovered metatarsal. These specimens display a combination of primitive and derived morphological features that is different from the combination of features found in other species in the genus Homo (including Homo floresiensis and Homo sapiens) and warrants their attribution to a new species, which we name Homo luzonensis. The presence of another and previously unknown hominin species east of the Wallace Line during the Late Pleistocene epoch underscores the importance of island Southeast Asia in the evolution of the genus Homo.

So here we have humans living in the Philippines 67 kya that differ from both Homo sapiens and the minute H Floresiensis.

It has a mosaic of archaic and modern features which highlights the presence of a wide diversity of hominins in Asia prior to the "Out of Africa" event. This surely combines Denisovan, Homo erectus and, perhaps H. habilis traits.

Asia will come up with plenty of surprises in the coming years, maybe they will debunk the Out of Africa theory...

This finding took place in the Callao Cave, which we reported in a previous post: Hominins in the Philippines 709,000 years ago: watercraft?

Let's wait for more discoveries.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2019 by Austin Whittall © 

Hominins in the Philippines 709,000 years ago: watercraft?

This paper published in Nature a few weeks ago: Earliest known hominin activity in the Philippines by 709 thousand years ago, by T. Ingicco et al. (Nature volume 557, pages 233–237 (2018) doi:10.1038/s41586-018-0072-8) is amazing: the authors find stone tools and the remains of butchered megafauna several hundreds of thousands of years older than expected. These hominins were not Homo sapiens, and the Philippines was separated from the rest of Sundaland by open sea. So how did they get there? Did they use boats?

The paper says the folowing:

• The remains are between 631 and 777 Ky old. So this is +600 ky older than the alleged Out of Africa event of modern humans.
• They found dozens of stone tools, rather primitive, lacking retouching.
• They also found rhinoceros bones with cut marks and percussion marks (to break the bones), a clear indication of hominin activities.

The authors write: "Our excavations at Kalinga and the numeric dating results clearly provide securely dated evidence for human colonization of the Philippines by the early Middle Pleistocene epoch, and long before the appearance of modern humans in both the local context and wider Island South East Asia region. Although the identity of these archaic toolmakers remains unknown, it is likely that they dispersed over at least one sea barrier to reach Luzon Island. The most likely points of origin are Borneo through Palawan to the west, or China through Taiwan to the north, this latter island was connected to mainland Asia during periods with low sea levels..."

Then they wonder if these hominins are related to more recent remains found at Callao Cave, those of a small adult human:

"...a question clearly linked to our discovery is the origin of the Callao Cave hominin that has been dated to 66.7 ± 1 ka. This diminutive Callao hominin may represent a direct descendent from a Pleistocene migration stock related to these early Kalinga toolmakers—similar to what happened on Flores Island—or may be derived from a more recent migration wave of anatomically modern humans..."

The Callao Cave hominin was reported (New evidence for a 67,000-year-old human presence at Callao Cave, Luzon, Philippines,Armand Salvador Mijares et al. Journal of Human Evolution Volume 59, Issue 1, July 2010, Pages 123-132 https://doi.org/10.1016/j.jhevol.2010.04.008) after the discovery of a metatarsal bone (foot bone) of a diminutive hominin, which may have been or not a modern human:

"[The] metatarsal definitely belongs to the genus Homo. Morphometric analysis of the Callao metatarsal indicates that it has a gracile structure, close to that observed in other small-bodied Homo sapiens. Interestingly, the Callao metatarsal also falls within the morphological and size ranges of Homo habilis and H. floresiensis. Identifying whether the metatarsal represents the earliest record of H. sapiens so far recorded anywhere east of Wallace’s Line".

So it may have been a Homo habilis or even a Flores hominin! or, as the authors of the most recent find suggest, a migration of Homo erectus (see below) that became tinier due to insular dwarfism, see what Ingicco et al say about the rhino slayers:

"Despite the current evidence, it still seems too farfetched to suggest that H. erectus, or another unknown Pleistocene ancestral candidate for the Kalinga toolmakers (for example, Denisovans), were able to construct some sort of simple watercraft and deliberately cross sea barriers to reach these islands. However, considering evidence of overseas dispersal during the Middle Pleistocene stage is increasing in number, such a hypothesis cannot currently be rejected."

For me the important thing is precisely that: they crossed open sea to reach the Philippines. This means they dominated the art of building and sailing watercraft long before humans appeared, at the time that Neanderthals were splitting from the ancestors of H. sapiens (if the Out of Africa theory is correct). But do note how hesitant the authors are, to admit this (they write "too farfetched" instead of admitting that they did build a boat...)

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall ©