Fish swam the Sahara, bolstering out of Africa theory

MSNBC: Fish swam the Sahara, bolstering out of Africa theory
Fish may have once swum across the Sahara, a finding that could shed light on how humanity made its way out of Africa, researchers said.

The cradle of humanity lies south of the Sahara, which begs the question as to how our species made its way past it. The Sahara is the largest hot desert in the world, and would seem a major barrier for any humans striving to migrate off the continent.

Scientists have often focused on the Nile Valley as the corridor by which humans left Africa. However, considerable research efforts have failed to uncover evidence for its consistent use by people leaving the continent, and precisely how watery it has been over time is controversial.

Now it turns out the Sahara might not have been quite as impassable as once thought — not only for humanity, but for fish as well.

"Fish appeared to have swam across the Sahara during its last wet phase sometime between 10,000 and 6,000 years ago," researcher Nick Drake, a geographer at King's College London, told LiveScience. "The Sahara is not a barrier to the migrations of animals and people. Thus it is possible — likely? —that early modern humans did so, and this could explain how we got out of Africa."

Using satellite imagery and digital maps of the landscape, the researchers found the Sahara was once covered by a dense network of rivers, lakes and inland deltas. This large waterway channeled water and animals into and across the Sahara during wet, "green" times. [ See digital map of ancient Sahara ]

In their analysis, Drake and his colleagues found evidence that many creatures, including aquatic ones, dispersed across the Sahara recently. For example, 25 North African animal species have populations both north and south of the Sahara with small refuges within the desert, including catfish (Clarias gariepinus), tilapia (Tilapia zillii), jewel cichlid fish (Hemichromis letourneuxi) and freshwater snails such as the red-rimmed melania (Melanoides tuberculata). Indeed, more animals may have once crossed over the Sahara than over the Nile corridor, the researchers said — only nine animal species that occupy the Nile corridor today are also found both north and south of the Sahara.

If fish could have crossed the Sahara, it is hard to imagine that humans didn't. Analysis of African languages and artifacts suggest that ancient waterways recently affected how humans occupied the Sahara. For instance, speakers of Nilo-Saharan languages once lived across central and southern Sahara, and may have once hunted aquatic creatures with barbed bone points and fish hooks. In addition, ancient lake sediments suggest the Sahara was green roughly 125,000 years ago, back when anatomically modern humans might have begun migrating out of Africa.

Future work could focus on when species got across the Sahara — genetic analysis of fish could help pinpoint such times in fish, Drake said. However, further research into the past of the Sahara could prove difficult and even dangerous, he noted. Some of the Saharan countries the researchers would like to visit in order to analyze the genetics of fish populations or date the ages of ancient shorelines "are deemed to be too dangerous to visit due to terrorist activity or civil war," Drake said.

The scientists detailed their findings online Dec. 27 in the journal Proceedings of the National Academy of Sciences.

Researchers: Ancient human remains found in Israel

What the Israeli archeologists have done here is ridiculous. They've found a single tooth and claim from this that mankind originated in Israel? I think not. Even as you read the article, another scientist says it is an "extremely remote" possibility.

Researchers: Ancient human remains found in Israel
JERUSALEM – Israeli archaeologists said Monday they may have found the earliest evidence yet for the existence of modern man, and if so, it could upset theories of the origin of humans.

A Tel Aviv University team excavating a cave in central Israel said teeth found in the cave are about 400,000 years old and resemble those of other remains of modern man, known scientifically as Homo sapiens, found in Israel. The earliest Homo sapiens remains found until now are half as old.

"It's very exciting to come to this conclusion," said archaeologist Avi Gopher, whose team examined the teeth with X-rays and CT scans and dated them according to the layers of earth where they were found.

He stressed that further research is needed to solidify the claim. If it does, he says, "this changes the whole picture of evolution."

The accepted scientific theory is that Homo sapiens originated in Africa and migrated out of the continent. Gopher said if the remains are definitively linked to modern human's ancestors, it could mean that modern man in fact originated in what is now Israel.

Sir Paul Mellars, a prehistory expert at Cambridge University, said the study is reputable, and the find is "important" because remains from that critical time period are scarce, but it is premature to say the remains are human.

"Based on the evidence they've sited, it's a very tenuous and frankly rather remote possibility," Mellars said. He said the remains are more likely related to modern man's ancient relatives, the Neanderthals.

According to today's accepted scientific theories, modern humans and Neanderthals stemmed from a common ancestor who lived in Africa about 700,000 years ago. One group of descendants migrated to Europe and developed into Neanderthals, later becoming extinct. Another group stayed in Africa and evolved into Homo sapiens — modern humans.

Teeth are often unreliable indicators of origin, and analyses of skull remains would more definitively identify the species found in the Israeli cave, Mellars said.

Gopher, the Israeli archaeologist, said he is confident his team will find skulls and bones as they continue their dig.

The prehistoric Qesem cave was discovered in 2000, and excavations began in 2004. Researchers Gopher, Ran Barkai and Israel Hershkowitz published their study in the American Journal of Physical Anthropology

Merry christmas to all

In whatever you conceive this season to be.

A video, which my Kindle readers can't view, unfortunately.

The New Seekers singing "I'd like to teach the world to sing"

(Go to Youtube and do a serch on the song if you'd like to hear it.)

Research: Pterygotid Sea Scorpions Not The Terror Of Ancient Seas

Underwater Times: Research: Pterygotid Sea Scorpions Not The Terror Of Ancient Seas

BUFFALO, New York -- Experiments by a team of researchers in New York and New Jersey have generated evidence that questions the common belief that the pterygotid eurypterids ("sea scorpions") were high-level predators in the Paleozoic oceans. This group, which ranged the seas from about 470 to 370 million years ago (long before the dinosaurs appeared), included the largest and, arguably, scariest-looking arthropods known to have evolved on planet Earth. Reaching lengths of 2 ½ meters with a body supported by well-developed legs, and armed with a pair of forward-facing claws laden with sharp projecting spines, they seem like the Tyrannosaurus rex among the invertebrates.

But in a new study, published in volume 39 of the Bulletin of the Buffalo Society of Natural Sciences, Richard Laub (Buffalo Museum of Science) and his colleagues Victor Tollerton (Research Associate, New York State Museum) and Richard Berkof (Stevens Institute of Technology) show that the mechanical constraints on the claw of the pterygotid sea scorpion Acutiramus made it incapable of penetrating the external shell of a medium-sized horseshoe crab without danger of rupturing. They suggest that these imposing sea scorpions, and by extension others of their family who lived in the seas about 470 to 370 million years ago, were not necessarily the voracious predators they are commonly believed to have been. The practical operational force that could be safely applied by the claw of Acutiramus without causing damage to it was no more than about 5 Newtons, whereas a force of 8-17 Newtons was required to penetrate the horseshoe crab's armor.

Laub's team also noted that the absence of an 'elbow joint' between the claws and the body of Acutiramus limited claw movement, making them more effective in grasping prey on the sea floor than capturing actively fleeing fish or other swimming animals. Armed with serrated spines, the claws may have been used together to both capture and shred the prey, but the predatory capabilities of Acutiramus would appear to lack the force necessary for this animal to operate as a major predator.

"I have long been suspicious of prevailing popular interpretations" said Dr. Roy Plotnick, Department of Earth and Environmental Sciences at the University of Illinois at Chicago, who was not involved in the study. "This is a welcome contribution that strongly supports an alternative interpretation of claw function" he said.

"Our results derail the image of these imposing-looking animals, the largest arthropods yet known to have existed, as fearsome predators, or at least as predators of other eurypterids and of the armored fishes of the time" said team leader Richard Laub, who noted that "it opens the possibility that they were scavengers or even vegetarians".

UK’s biggest CT scan to be used on fossil

Indie Pro Pub: UK’s biggest CT scan to be used on fossil
British scientists are using the country’s most powerful CT scanner to investigate a recently found fossil of one of the world’s most ferocious sea monsters of pre-historic times.

The fossil, found recently along the U.K.’s Jurassic coast, belongs to a pliosaur and is considered the largest fossil of this predator ever found. At 2.4 meters long (7.9 feet), with a crocodile-like head, paddle-like limbs, and razor sharp teeth, it ruled the oceans 150 million years ago. With a skull measurement like this, the monster would have been 10-16 meters (33-52 feet) long and weigh up to 12 tonnes.

The CT scan will x-ray the skull and provide 3D pictures and will, scientists hope, determine if this particular giant is a new species. The skull is being gently worked out of the rock by preparator Scott Moore-Fay, and is expected to take more than 1,000 hours of intense and careful labor.

Moore-Fay was excited to be able to use the CT scan and said equipment like this will prevent any damage from occurring to the fossil.

The funding for the scanner has been provided by the Engineering Physical Science Research Council (EPSRC) and the University of Southampton, and is the largest and most powerful CT scanner in the U.K.

University of Southampton engineer Dr. Mark Mavrogordato said a 3D picture representing the original specimen would be the end result, which can be sliced and diced however needed, almost if being dissected by knife, only digitally and non-destructively.

Richard Forrest, team Palaeontologist, said, after examining the fossil and noting the hidden teeth, that the creature had an enormously powerful bite, and could have bitten a car in half.

But one the main goals is to determine if it is a new species to science.

Forrest said from the outside it looks similar to other pliosaurs found, just much bigger, but internal investigations will reveal if this species has not been seen before.

The fossil will eventually be mounted and displayed at the Dorset County Museum in 2011, in Dorchester, with mouth agape, and with a life size model of its head beside it so visitors can see exactly how large and terrifying it really was.