Saturday, April 22, 2017

Hobbits Are Not Dwarf H. Erectus

Most people had already rejected the theory that H. florensiensis (Hobbits) were diseased humans. But, this new physical anthropology study rules out the possibility that they are derived from H. erectus, because their bones show more primitive and basal features.

The is notable because it also largely rules out the theory that Hobbits are a subtype of Denisovans or H. heidelbergensis. Instead, it seems likely that they left Africa before or contemporaneously with H. erectus and are closer to H. habilis than any other known species of Homo.
The most comprehensive study on the bones of Homo floresiensis, a species of tiny human discovered on the Indonesian island of Flores in 2003, has found that they most likely evolved from an ancestor in Africa and not from Homo erectus as has been widely believed. The study by The Australian National University (ANU) found Homo floresiensis, dubbed "the hobbits" due to their small stature, were most likely a sister species of Homo habilis -- one of the earliest known species of human found in Africa 1.75 million years ago. 
Data from the study concluded there was no evidence for the popular theory that Homo floresiensis evolved from the much larger Homo erectus, the only other early hominid known to have lived in the region with fossils discovered on the Indonesian mainland of Java. . . .
Homo floresiensis is known to have lived on Flores until as recently as 54,000 years ago.
The study was the result of an Australian Research Council grant in 2010 that enabled the researchers to explore where the newly-found species fits in the human evolutionary tree. 
Where previous research had focused mostly on the skull and lower jaw, this study used 133 data points ranging across the skull, jaws, teeth, arms, legs and shoulders. 
Dr Argue said none of the data supported the theory that Homo floresiensis evolved from Homo erectus. 
"We looked at whether Homo floresiensis could be descended from Homo erectus," she said. 
"We found that if you try and link them on the family tree, you get a very unsupported result. All the tests say it doesn't fit -- it's just not a viable theory." 
Dr Argue said this was supported by the fact that in many features, such as the structure of the jaw, Homo floresiensis was more primitive than Homo erectus. 
"Logically, it would be hard to understand how you could have that regression -- why would the jaw of Homo erectus evolve back to the primitive condition we see in Homo floresiensis?" 
Dr Argue said the analyses could also support the theory that Homo floresiensis could have branched off earlier in the timeline, more than 1.75 million years ago. 
"If this was the case Homo floresiensis would have evolved before the earliest Homo habilis, which would make it very archaic indeed," she said. 
Professor Mike Lee of Flinders University and the South Australian Museum, used statistical modeling to analyse the data. 
"When we did the analysis there was really clear support for the relationship with Homo habilis. Homo floresiensis occupied a very primitive position on the human evolutionary tree," Professor Lee said. 
"We can be 99 per cent sure it's not related to Homo erectus and nearly 100 per cent chance it isn't a malformed Homo sapiens," Professor Lee said.
From Science News.
Although the diminutive Homo floresiensis has been known for a decade, its phylogenetic status remains highly contentious. A broad range of potential explanations for the evolution of this species has been explored. One view is that H. floresiensis is derived from Asian Homo erectus that arrived on Flores and subsequently evolved a smaller body size, perhaps to survive the constrained resources they faced in a new island environment. Fossil remains of H. erectus, well known from Java, have not yet been discovered on Flores. The second hypothesis is that H. floresiensis is directly descended from an early Homo lineage with roots in Africa, such as Homo habilis; the third is that it is Homo sapiens with pathology. 
We use parsimony and Bayesian phylogenetic methods to test these hypotheses. Our phylogenetic data build upon those characters previously presented in support of these hypotheses by broadening the range of traits to include the crania, mandibles, dentition, and postcrania of Homo and Australopithecus. 
The new data and analyses support the hypothesis that H. floresiensis is an early Homo lineage: H. floresiensis is sister either to H. habilis alone or to a clade consisting of at least H. habilis, H. erectus, Homo ergaster, and H. sapiens. A close phylogenetic relationship between H. floresiensis and H. erectus or H. sapiens can be rejected; furthermore, most of the traits separating H. floresiensis from H. sapiens are not readily attributable to pathology (e.g., Down syndrome). The results suggest H. floresiensis is a long-surviving relict of an early (>1.75 Ma) hominin lineage and a hitherto unknown migration out of Africa, and not a recent derivative of either H. erectus or H. sapiens.
Debbie Argue, Colin P. Groves, Michael S.Y. Lee, William L. Jungers. "The affinities of Homo floresiensis based on phylogenetic analyses of cranial, dental, and postcranial characters." Journal of Human Evolution (April 2017(.

Friday, April 21, 2017

Oldest Temple In World May Have Been Built In Reaction To A Comet Impact

From the LGM to the Younger Dryas

The Last Glacial Maximum (LGM) was the low point of the last major ice age and took place ca. 18,000 BCE. At that time, most of Europe, Siberia and North America were covered with thick glaciers, human in Europe were confined to three small refugia.

The water used in the glaciers and associated polar ice packs greatly lowered the sea level on Earth, connecting the British Isles and Continental Europe with a land bridge; giving rise to a land bridge across the Bering Strait; connecting many islands in island Southeast Asia to each other and the mainland; connecting Papua New Guinea, Australia and the island of Tasmania; making the water passage to the Andaman Island from mainland Southeast Asia much less daunting; and making it easier to reach Japan from mainland East Asia.

As the Earth warmed up again following the LGM, sea levels rose and the glaciers retreated. This allowed the founding population of the Americas expanded from Beringia into North and South America (ca. 12,000-13,000 BCE), and hunter-gatherers from the European refugia and the Near East repopulated Europe, while those hunter-gatherers and others from Asian refugia repopulated Siberia. Populations in the Americas were isolated from the rest of the world. Island Southeast Asians were isolated from mainland Asia and each other. Papua New Guinea was isolated from Australia. And, the Andaman Islands and Japan became more inaccessible from the mainland. Proto-farming was starting to develop in the Fertile Crescent in the Near East (Mesopotamia, Anatolia and the Levant).

Just as the climate was becoming tolerable for farming in many places, the Younger Dryas event occurred. This was a sudden, global, extreme cooling event that started around 10,800 BCE and lasted about 1400 years. This plunged the world into another severe ice age, although not quite as deep an ice age as the LGM. As noted by an author of a paper discussed last month at this blog:
"[T]he Younger-Dryas coincides with the end of Clovis culture and the extinction of more than 35 species of ice-age animals. Moore says while evidence has shown that some of the animals were on the decline before Younger-Dryas, virtually none are found after it. Moore says that would indicate an extinction event for North America." The animals that went extinct included the mastodon, mammoth and saber-toothed tiger.
So climate change, as well as overhunting, appears to have played an important part in the North American megafauna extinction.

Global deposits of rare elements at the time of the Younger Dryas event similar to those found at the CT boundary created by the comet that destroyed the dinosaurs ca. 65 million years ago have made it increasingly clear that the Younger Dryas event was also caused by an extraterrestrial impact, probably by a comet or asteroid about two-thirds of a mile (one kilometer) in diameter, probably originating in the the Taurid meteor stream given its timing, which has now been established quite precisely.

The place where the Younger Dryas object hit the Earth has not yet been identified. This is in some ways a more difficult task because the impact was smaller, but this difficulty is compensated for, in part, because the Younger Dryas impact was much more recent.

Göbekli Tepe

A National Geographic artists impression of Göbekli Tepe shortly after it was completed.  

The Göbekli Tepe in Southeast Anatolia is a sophisticated stone edifice with carved imagines on it that is arguably the earliest temple or astronomical monument in the world. It is located atop a mountain ridge in the Southeastern Anatolia Region of modern-day Turkey, approximately 12 km (7 mi) northeast of the city of Şanlıurfa, not far north of the middle of the border between Syria and Turkey. The tell has a height of 15 m (49 ft) and is about 300 m (980 ft) in diameter. It is approximately 760 m (2,490 ft) above sea level. It is near the northern peak of the Fertile Crescent.

This is particularly notable because it was built by hunter-gathers before crops or farm animals had been domesticated (although domesticated dogs did exist by that point). Its construction coincides with the Younger Dryas event and it was used for about 2,000 years thereafter (i.e. until about 8,000 BCE) this time period corresponds the the archaeological periods in the Near East known as Pre-pottery Neolithic A (PPNA) and Pre-pottery Neolithic B (PPNB).

A new study suggests that the timing of its construction very close in time to the Younger Dryas event was no coincidence. Instead, Göbekli Tepe was probably the response of this community of hunter-gatherers to the Younger Dryas event. It was an observatory as much as it was a temple.
We have interpreted much of the symbolism of Göbekli Tepe in terms of astronomical events. By matching low-relief carvings on some of the pillars at Göbekli Tepe to star asterisms we find compelling evidence that the famous ‘Vulture Stone’ is a date stamp for 10950 BC ± 250 yrs, which corresponds closely to the proposed Younger Dryas event, estimated at 10890 BC. We also find evidence that a key function of Göbekli Tepe was to observe meteor showers and record cometary encounters
Indeed, the people of Göbekli Tepe appear to have had a special interest in the Taurid meteor stream, the same meteor stream that is proposed as responsible for the Younger-Dryas event. Is Göbekli Tepe the ‘smoking gun’ for the Younger-Dryas cometary encounter, and hence for coherent catastrophism?
Martin B. Sweatman and Dimitrios Tsikritsis, "Decoding Göbekli Tepe with archaeoastronomy: What Does The Fox Say?", 17(1) Mediterranean Archaeology and Archaeometry, 233-250 (2017).

Hat tip to Dienekes' Anthrpology BlogThe title of the paper is a silly allusion to a cult classic cute little pop song with international distribution by international artist Ylvis, who has an interest in archaeological (having also written a song about Stonehenge), whose lyrics discuss the sounds that various kinds of animals make, as well as a reference to one of the carvings at the monument.

Did Bell Beaker People Introduce Modern European Dogs?

Dogs similar to modern European dog breeds start to appear in Europe in about the same time and places as the Bell Beaker people and in at least one instance, accompanying a Bell Beaker man in his burial.