Sayyid Azim / AP file

Scientist's at work in the National Museum of Kenya in Nairobi in 2007. As this African nation prepared to unveil 'Turkana Boy' more than two decades after his discovery, his first public outing created a storm.

By Tia Ghose
LiveScience

"Turkana Boy," an exquisitely preserved 1.5-million-year-old human ancestor found in Kenya, may not have had dwarfism or scoliosis, new research suggests.

Past studies had suggested that the ancient human ancestor, a Homo erectus, had suffered from a congenital bone disorder that made him unrepresentative of his species.

"Until now, the Turkana Boy was always thought to be pathological," said study co-author Martin Häusler, a physician and physical anthropologist at the University of Zurich. "The spine was somewhat weird, and so he couldn't be used as a comparative model for Homo erectus biology because he was so pathological."

But the new analysis, published in the March issue of the American Journal of Physical Anthropology, suggests that apart from a herniated disc in his back, Turkana Boy was a fairly healthy person with no genetic bone problems. [The 9 Most Bizarre Medical Conditions]

Exquisite find
The exquisitely preserved fossil, unearthed near the shores of Lake Turkana in Kenya in 1984, is the most complete early human skeleton ever found. The ancient hominid was likely a child or an adolescent Homo erectus who lived and died about 1.5 million years ago.

But about a decade ago, researchers proposed that Turkana Boy was suffering from a congenital deformation of the spine —possibly dwarfism or scoliosis.

To find out, Häusler and his colleagues carefully reanalyzed the skeletal bones. When they arranged the ribs as they were originally laid out, they got an asymmetrical back and rib cage.

"The ribs were arranged in the wrong way originally, and then you get this asymmetry, which is essentially not there," Häusler told LiveScience.

By rearranging the bones, the researchers found that Turkana Boy actually had a symmetrical spine and rib cage, meaning he wasn't suffering from dwarfism or scoliosis. As a result, it's fair game to make conclusions about the species' anatomy based on the skeleton, Häusler said.

The ancient hominid did show evidence of some vertebral misalignment, consistent with having a herniated disc — an injury that may have contributed to his death, Häusler said.

Controversial results
The new study is an excellent analysis, wrote Henry McHenry, an anthropologist at the University of California, Davis, who was not involved in the study. Häusler "has a special perspective in being an orthopedic surgeon with years of experience with original fossils in Africa and huge collections of modern humans and apes."

But not everyone is convinced.

"His axial skeleton is distinctive and bears evidence of some significant pathology," wrote Scott Simpson, an anthropologist at Case Western Reserve University in Ohio who was not involved in the study, in an email. "Clearly, some of the characteristics recognized in (Turkana Boy) would be characterized as congenital pathologies, perhaps in addition to traumatic injuries."

Follow Tia Ghose on Twitter @tiaghose. Follow LiveScience @livescience, Facebook and Google+. Original article on LiveScience.com

• 8 Grisly Archaeological Discoveries
• Top 10 Mysteries of the First Humans
• Image Gallery: Our Closest Human Ancestor

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Jeff Gage / University of Florida

Lower jaw fossils of a 5-million-year-old saber-toothed cat (Rhizosmilodon fiteae), a smaller relative of the Smilodon species, have been found in Florida.

By Tanya Lewis
LiveScience

A new genus and species of extinct saber-toothed cat has been found in Polk County, Fla., scientists say.

The fossil, which is 5 million years old, is related to the well-known carnivorous predator Smilodon fatalis from the La Brea Tar Pits of Los Angeles. The group of saber-toothed cats called Smilodontini was thought to have originated in the Old World and later migrated to North America, but the new species' age suggests the group evolved in North America, researchers reported Wednesday in the journal PLOS ONE.

Although Smilodon appears in the fossil record about 2.5 million years ago, there weren't many intermediate forms to tell scientists where it originated, according to study co-author Richard Hulbert Jr., vertebrate paleontology collections manager at the Florida Museum of Natural History.

"The new species shows that the most famous saber-toothed cat, Smilodon, had a New World origin, and it and its ancestors lived in the southeastern U.S. for at least 5 million years before their extinction about 11,000 years ago," Hulbert said in a statement. "Compared to what we knew about these earlier saber-toothed cats 20 or 30 years ago, we now have a much better understanding of this group."

Hulbert and colleagues discovered the fossils of the new cat, Rhizosmilodon fiteae, during the excavation of a phosphate mine in 1990. The species was named for Barbara Fite of Lutz, Fla., who donated a fossil of the species from her collection that had a very well-preserved lower jaw with all three chewing teeth. The name Rhizosmilodon means "root of Smilodon," because researchers believe the creature could be the direct ancestor of Smilodon, which went extinct 11,000 years ago.

The researchers did a comparative analysis of saber-toothed cat anatomy to determine its biological grouping. The animal's lower jaw and teeth were smaller than Smilodon's, about the size of a modern Florida panther, the results showed. [Image Gallery: 25 Amazing Ancient Beasts]

When alive, the panther-size cat would've lived alongside rhinos, tapirs, three-toed horses, peccaries, llamas and deer in a coastal forest. There, the researchers suspect, Rhizosmilodontook advantage of its small size to climb trees and hide captured prey from larger meat-eaters including packs of hyena dogs and an extinct bear larger than today's grizzly.

The new cat was originally misidentified from a partial lower jaw fossil in the early 1980s as a member of the genus Megantereon. The cat is actually a sister species to Megantereon and Smilodon, but is older than either group. All three are called saber-toothed cats because of their long canine teeth.

"When people think of saber-toothed cats, they think of it as just one thing," Hulbert said, "when in fact, it was an almost worldwide radiation of cats that lasted over 10 million years and probably had a total of about 20 valid species."

The finding helps settle the debate over where saber-toothed cats first arose — in North America, rather than Eurasia.

Follow Tanya Lewis @tanyalewis314. Follow us @livescience, Facebook or Google+. Original article on LiveScience.com.

• In Photos: Top 10 Deadliest Animals
• Iconic Cats: All 9 Subspecies of Tiger
• Here Kitty, Kitty: 10 Facts for Cat Lovers

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Julius Csotonyi

The giant ancestor of the modern camel lived in Arctic forests.

The ancestors of the modern camel included an Arctic giant that lived in chilly coniferous forests about 3.5 million years ago. The ancient ungulates were 30 percent bigger than living camels today, weighing about a ton.

Scientists pieced together a picture of this camel from a crop of 30 fossilized bone fragments found on Ellesmere Island in the Canadian Arctic. It's the first evidence that camel ancestors lived so far north. The location and age of the bone fragments indicate that the camel lived at time when the planet was 5.4 degrees Fahrenheit (3 degrees Celsius) warmer than it is today, when parts of the Arctic were covered in coniferous forests filled with larch and birch. The Ellesmere Island region itself was about 36 degrees F (20 degrees C) warmer than it is today.

"Being big was something camels did very well," Natalia Rybczynski, a research scientist at the Canadian Museum of Nature told NBC News. "An animal today that would be an analogue is the moose — it's huge," she added. A large body size would have allowed it to regulate its body temperature better during the winters and cover larger distances walking, she explained. Rybczynski and her collaborators described the fossil and its analysis in a paper published Tuesday in Nature Communications.

Today's living camels have broad, flat feet, to help them walk on sand. Those feet could have evolved in an Arctic camel to walk on snow, Rybczynski says. And the ability to pack away fat, as the modern camel does in its hump, could have been useful to an Arctic camel that needed to survive dark, snowy winters that were six months long. 

Martin Lipman/Canadian Museum of Nature

These 30 fossil bone fragments belong to the tibia of a 3.5 million year-old camel ancestor.

Martin Lipman/Canadian Museum of Nature

This fossil chunk of the camel looks similar to wood. "You pick up everything that might be a fossil," Natalia Rybczynski says. When the day's find is analyzed back at camp, there are sometimes pleasant surprises. "We get back and say, 'Oh, it's not a piece of wood, it's a bone!'"

Rybczynski found the first fragment of the specimen in 2006. Over later visits in 2006, 2008 and 2010, she and her collaborators assembled a collection of 30 bone fragments that fit together to resemble the tibia of a large ungulate. A closer analysis of the structure of the bone hinted that they had a large cud chewer on their hands. 

For further proof, the team extracted collagen, a protein, from the fossils. Frozen in the Arctic mud, the biological molecule was preserved exceptionally well, and it survived better than ancient DNA would have fared. "It's mummified," Rybczynski said. Collagen isn't as information-rich as DNA, but has enough of a chemical fingerprint to show which family of animals the fragments came from. The ancient northern camel is related to today's dromedary, and to another now-extinct camel relative called the Yukon camel.

The high Arctic camel's fossil traces suggest that weird adaptations found in the modern camel may have arisen to fill a different need in its ancestors, and serve as a historical example of a species that lived on a planet that was warmer than it is today. That's what makes the fossil hunt fun fo Rybczynski. "You can pick up these tiny fragments that are that big, that makes these connections," she says. 

Nidhi Subbaraman writes about science and technology. Follow on Google+, Twitter, Facebook. 

Ray Troll

This is a re-creation of a Helicoprion, which lived 270 million years ago and is the only animal ever with a complete 360-degree spiral of teeth.

By Jennifer Viegas
Discovery

The world’s only animal, past or present, with a complete 360-degree spiral of teeth was Helicoprion, which sliced into prey like a buzzsaw.

This sharklike fish, which lived 270 million years ago, is described in the latest issue of Biology Letters. It had one of the most unusual mouths and sets of teeth in the animal kingdom.

"When the animal closed its mouth on prey, the spiral of sharp teeth rotated backwards, like a circular saw, and slashed through the meat,” lead author Leif Tapanila, an associate professor in the Department of Geosciences at Idaho State University, told Discovery News.

PHOTOS: Living Fossils, Animals From Another Time

Tapanila is also the research curator and head of the Earth Sciences Division at the Idaho Museum of Natural History. For the study, he and his colleagues took the first ever 3-D images of Helicoprion remains.

Scientists have puzzled over this animal for more than a century, given its highly unusual "tooth whorl.” The new research sheds light on what this prehistoric marine species looked like, what its ancestry was and how it behaved.

"Helicoprion looked a lot like a big-bodied modern shark, but it had a very unusual mouth,” Tapanila said. "An arc of 15 to 18 serrated teeth were exposed in the center of its lower jaw, and it had no protruding teeth in the upper jaw.”

Ray Troll

Leif Tapanila, an associate professor in the Department of Geosciences at Idaho State University, with the Helicoprion fossil.

The buzz saw-looking tooth whorl had two functions, the researchers determined. The outermost part anchored the teeth for biting, while the rest of the inner spiral was designed to house the old and previously used teeth from when the animal was younger.

The scientists did not see much wear, tear and breakage, so they suspect Helicoprion primarily sliced into squid or other ancient relatively soft and somewhat chewy sea life. Aside from squid and their early relatives, armored and cartilaginous fish lived in Helicoprion’s ecosystem, along with brachiopods, bivalves and snails. "Cartilaginous” refers to fish made up of cartilage, a firm yet flexible connective tissue.

While Helicoprion looked and acted like a shark, the researchers determined that it’s at the base of the family tree that today includes chimaera (aka "ghost sharks”) and ratfish. Ghost sharks are not technically sharks, but they look and act a lot like them.

Tapanila explained that cartilaginous fish are divided into two main categories: sharks and rays on one side, ratfish and chimaera on the other. They are all marine predators.

NEWS: Shark-Headed Human Ancestor Swam With Fishes

No living land or sea animal directly resembles Helicoprion -- especially it’s buzz-saw tooth whorl.

"It was really an improbable animal, and maybe one of the best examples of a successful ‘Hopeful Monster,’” Tapanila said, explaining that this refers to evolutionary processes that can result in very unusual body types, with most doomed to failure.

While Helicoprion eventually went extinct, it used to have a nearly global distribution and existed over a period of 10 million years or more, proving that even some eccentric body designs can be successful if they meet the particular needs influenced by the animal’s environment, food sources and more.

John Long, a professor of paleontology at Flinders University, told Discovery News that he fully supports the new findings about Helicoprion and its kin.

"This study ends a century old mystery about this iconic fossil (species) and highlights the unexpected diverse body form that holocephalans occupied,” Long said.

Tapanila and his team would love to find a fossilized prey animal in the mouth of such a prehistoric shark-like animal, to better determine which exact species they were hunting and eating. Given that they lived even before the dinosaurs, Tapanila isn’t "holding his breath” for such a rare find.

Dmitry Bogdanov

The ancient newfound crocodilian Tyrannoneustes lythrodectikos (shown here in an artist's rendering) would have devoured giant prey some 165 million years ago.

By Charles Choi
LiveScience

Long-forgotten remains of a giant dolphin-shaped crocodilian "super-predator" that could devour ancient beasts its size and larger have now been discovered in a museum drawer in Scotland, researchers say.

The ancient newfound crocodilian is named Tyrannoneustes lythrodectikos, which in ancient Greek means "blood-biting tyrant swimmer."

"Tyrannoneustes was a dolphinlike crocodile that lived 165 million years ago," said researcher Mark Young, a vertebrate paleontologist at the University of Edinburgh in Scotland and the University of Southampton in England.

The predator possessed a long snout, large flippers, armorless skin and a tail fin where the bottom half is larger than the top half, resembling an upside-down version of an ordinary shark's tail fin. It's uncertain how large Tyrannoneustes was, but the right side of its lower jaw was at least 26 inches (67 centimeters) long.

Tyrannoneustes was a super-predator, meaning it evolved to devour prey its size and larger. Features of its lower jaw and teeth reveal the beast was suited for swallowing smaller prey whole or slicing larger prey into pieces small enough to swallow. [ Image Gallery: Ancient Monsters of the Sea ]

"These features include enlarged teeth, teeth with serrated edges and a change in the shape of the lower jaw that allowed it to open wider," Young told LiveScience.

Mark Young

It's uncertain how large the super-predator Tyrannoneustes was, but the right side of its lower jaw (shown here) was at least 26 inches (67 cm) long.

Back when Tyrannoneustes was alive, the area in central England where the fossils were discovered was covered in a shallow sea encompassing much of what is now Europe.

"At that time, Europe would have been an archipelago with some larger landmasses," Young said. Europe was also farther south back then, meaning sea-surface temperatures were balmy, ranging from 68 to 80 degrees Fahrenheit (20 to 27 degrees Celsius). The area Tyrannoneustes was found in also held a diverse group of other marine reptiles, such as other marine crocodilians, the vaguely Loch Ness Monster-shaped plesiosaurs and pliosaurs, and the dolphin-shaped ichthyosaurs, as well as fish and squid.

The fossils were originally discovered in clay pits by fossil hunter Alfred Leeds some time between 1907 and 1909. They languished in a drawer in the Hunterian Museum and Art Gallery in Glasgow, Scotland, until Young and his colleagues rediscovered them.

"It had lain there for almost 100 years," Young said.

No modern crocodiles are descended from Tyrannoneustes. Instead, this predator was a kind of metriorhynchid, an extinct family of marine crocodiles.

"This new species fills an evolutionary gap in the metriorhynchid fossil record," Young said. "The discovery of Tyrannoneustes shows that during the Middle Jurassic, metriorhynchid crocodiles were beginning to evolve into predators of large-bodied prey. By the Late Jurassic, numerous metriorhynchid species were suited to feeding on large prey, but Tyrannoneustes is the first known from the Middle Jurassic. How this impacted upon other predatory groups such as pliosaurs and ichthyosaurs is still unclear."

Future research can scan Tyrannoneustes bones to develop computer models of how it might have fed, Young said. He and his colleagues detailed their findings online Jan. 4 in the Journal of Systematic Palaeontology.

Follow LiveScience on Twitter @livescience. We're also on Facebook   and Google+.

• 6 Strange Species Discovered in Museums
• Image Gallery: Photos Reveal Prehistoric Sea Monster
• Loch Ness Madness: Our 10 Favorite Monsters

Robert Boessenecker

An artist's rendition of the extinct walrus, Pelagiarctos thomasi.

By Megan Gannon, LiveScience

A "killer walrus" thought to have terrorized the North Pacific 15 million years ago may not have been such a savvy slayer after all, researchers say.

A new analysis of fossil evidence of the prehistoric beast shows it was more of a fish-eater than an apex predator with a bone-crushing bite.

Traces of the middle Miocene walrus, named Pelagiarctos thomasi, were first found in the 1980s in the Sharktooth Hill bone bed of California. A chunk of a robust jawbone and sharp pointed teeth, which resembled those of the bone-cracking hyena, led researchers to believe the walrus ripped apart birds and other marine mammals in addition to the fish that modern walruses eat today.

But a more complete lower jaw and teeth from the long-gone species were recently discovered in the Topanga Canyon Formation near Los Angeles. Researchers say the shape of the teeth from this new specimen suggest the walrus was unlikely adapted to regularly feed on large prey. Instead, they think it was a generalist predator, feasting on fish, invertebrates and the occasional warm-blooded snack.

"When we examined the new specimen and the original fossils, we found that the teeth really weren't that sharp at all — in fact, the teeth looked like scaled-up versions of the teeth of a much smaller sea lion," researcher Robert Boessenecker, a geology doctoral student at the University of Otago in New Zealand, told the PLOS ONE Community Blog.

Using a model to estimate body size based on the size of the jaw, Boessenecker and Morgan Churchill of the University of Wyoming found that Pelagiarctos was quite large — about 770 pounds (350 kilograms), or similar in size to some modern male sea lions. But they noted that a big body alone likely wouldn't indicate that the species was a dominant predator. That's because both large and small modern species in the pinniped family — which includes seals, sea lions and walruses — are dietary generalists that tend to eat mostly fish.

Boessenecker added that the new findings give a clearer picture of the modern walrus' evolutionary past. [ Fun Facts About Walruses ]

"Right now, there is only one modern walrus species but back then, walruses were a very diverse group," the researcher told the PLOS blog. "Many of these other extinct walruses had strange adaptations — such as the development of upper and lower tusks, gigantic body size, ultradense bones, unusually short forelimbs, and even the loss of all teeth aside from tusks. The myriad types of extinct walruses — Pelagiarctos included — beautifully demonstrate the often convoluted path that evolution can take."

The study was published online Jan. 16 in the journal PLOS ONE. Funding came from the University of Otago, the Geological Society of America, The Palaeontological Society, and the National Science Foundation.

Follow LiveScience on Twitter@livescience. We're also on Facebook & Google+.

• Giants on Ice: Gallery of Walruses
• Image Gallery: Photos Reveal Prehistoric Sea Monster
• 25 Amazing Ancient Beasts

© 2012 LiveScience.com. All rights reserved.

Stephanie Abramowicz

A fossil skeleton of a toothed bird has been unearthed in China. The Cretaceous Era bird had specialized teeth for cracking open hard foods such as insects or snails.

By Tia Ghose, LiveScience

The fossil skeleton of a bird with strange teeth that lived 125 million years ago has been discovered in China. The bird had bizarre ridges on its teeth that may have enabled it to crack open hard-shelled insects and snails, the researchers said.

The unusual fossil, described in the January issue of the Journal of Vertebrate Paleontology, was so well preserved that some of its stomach contents were still present. The new find sheds light on the range of foods Earth's earliest birds ate during the dinosaur era.

"The teeth are weird and there are some stomach contents, which is unusual," said paleontologist Gareth Dyke, of the University of South Hampton in the U.K., who was not involved in the study. "It's more evidence for the uniqueness and range of ecological specialization that are seen in these particular Mesozoic birds."

Teeming with life
The new species' specimen was unearthed in the Liaoning province in China, where many fossils from the Cretaceous Period (the period from 145 million to 65 million years ago that was the end of the Mesozoic Era) have been found over the last 15 years, said study author Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles. The primeval forest was teeming with ancient life, from pterodactyls and dinosaurs such as the microraptor to primitive lizards and various trees. The skies were also filled with birds, he said.

"This was clearly a hotspot of ancient bird biodiversity," Chiappe told LiveScience.

Stephanie Abramowicz

The well-preserved Sulcavis geeorum teeth still had enamel on them.

Toothy bird
The newly discovered bird, a robin-size creature called Sulcavis geeorum, lived between 121 million and 125 million years ago. Sulcavis geeorum belonged to a class of extinct toothed birds called Enantiornithines, which were the most numerous birds during the age of dinosaurs. The diminutive creature looked somewhat similar to modern-day songbirds, with a key difference: the bird had some very strange teeth. [ Album: 25 Amazing Ancient Beasts ]

The teeth of this tiny flier had sharp, pointy crowns. In addition, the fossil found by Chiappe's team had preserved tooth enamel that formed serrated ridges. Those serrated ridges probably enabled the birds to crack open the hard exoskeletons of insects, crabs or snails, Chiappe said.

The strange teeth may shed light on a prehistoric mystery of sorts: No one knows exactly why early birds had teeth. It's also unclear why they have lost their teeth at least four times since they first emerged in the fossil record. In fact, modern-day birds still have genes for teeth, but the genes are turned off, Chiappe said.

"The traditional view is that teeth are heavy, and the birds evolved beaks as a way of making their bodies lighter. These teeth are pretty small and it's hard to imagine that they had such a huge impact on the weight of the animal," he said.

Follow LiveScience on Twitter@livescience. We're also onFacebook &Google+.

• Image Gallery: Dinosaur Fossils
• Avian Ancestors: Dinosaurs That Learned to Fly
• Image Gallery: Dinosaur Daycare

© 2012 LiveScience.com. All rights reserved.