Paleonews

Il blog dedicato ai Paleontologi !!!!

2009-07-04 – Myanmar: nuovo Primate fossile (new fossil Primate)

New Fossil Primate Suggests Common Asian Ancestor, Challenges Primates Such As ‘Ida’

ScienceDaily (July 1, 2009) — According to new research published online in the Proceedings of the Royal Society B (Biological Sciences) on July 1, 2009, a new fossil primate from Myanmar (previously known as Burma) suggests that the common ancestor of humans, monkeys and apes evolved from primates in Asia, not Africa as many researchers believe.

The discovery of this new fossil primate from Myanmar (previously known as Burma) suggests that the common ancestor of humans, monkeys and apes evolved from primates in Asia, not Africa as many researchers believe. (Credit: Mark A. Klingler/Carnegie Museum of Natural History)

The discovery of this new fossil primate from Myanmar (previously known as Burma) suggests that the common ancestor of humans, monkeys and apes evolved from primates in Asia, not Africa as many researchers believe. (Credit: Mark A. Klingler/Carnegie Museum of Natural History)

A major focus of recent paleoanthropological research has been to establish the origin of anthropoid primates (monkeys, apes and humans) from earlier and more primitive primates known as prosimians (lemurs, tarsiers and their extinct relatives). Prior to recent discoveries in China, Thailand, and Myanmar, most scientists believed that anthropoids originated in Africa. Earlier this year, the discovery of the fossil primate skeleton known as “Ida” from the Messel oil shale pit in Germany led some scientists to suggest that anthropoid primates evolved from lemur-like ancestors known as adapiforms.

According to Dr. Chris Beard–– a paleontologist at Carnegie Museum of Natural History in Pittsburgh, Pennsylvania and a member of the international team of researchers behind the Myanmar anthropoid findings––the new primate, Ganlea megacanina, shows that early anthropoids originated in Asia rather than Africa. These early Asian anthropoids differed radically from adapiforms like Ida, indicating that Ida is more closely related to modern lemurs than it is to monkeys, apes and humans.

The 38-million-year-old Ganlea megacanina fossils, excavated at multiple sites in central Myanmar, belong to a new genus and species. The name of the new species refers to a small village, Ganle, near the original site where the fossils were found, and the greatly enlarged canine teeth that distinguish the animal from closely related primates. Heavy dental abrasion indicates that Ganlea megacanina used its enlarged canine teeth to pry open the hard exteriors of tough tropical fruits in order to extract the nutritious seeds contained inside.

“This unusual type of feeding adaptation has never been documented among prosimian primates, but is characteristic of modern South American saki monkeys that inhabit the Amazon Basin,” says Dr. Beard. “Ganlea shows that early Asian anthropoids had already assumed the modern ecological role of modern monkeys 38 million years ago.”

Ganlea and its closest relatives belong to an extinct family of Asian anthropoid primates known as the Amphipithecidae. Two other amphipithecids, Pondaungia and Myanmarpithecus, were previously discovered in Myanmar, while a third, named Siamopithecus, had been found in Thailand. A detailed analysis of their evolutionary relationships shows that amphipithecids are closely related to living anthropoids and that all of the Burmese amphipithecids evolved from a single common ancestor. Some scientists had previously argued that amphipithecids were not anthropoids at all, being more closely related to the lemur-like adapiforms.

The discovery of Ganlea strongly supports the idea that amphipithecids are anthropoids, because adapiforms never evolved the features that are necessary to become specialized seed predators. Indeed, all of the Burmese amphipithecids appear to have been specialized seed predators, filling the same ecological niche occupied by modern pitheciine monkeys in the Amazon Basin of South America. During the Eocene when Ganlea and other amphipithecids were living in Myanmar, they inhabited a tropical floodplain that was very similar to the environment of the modern Amazon Basin.

Fossils of Ganlea megacanina were first discovered in Myanmar in December 2005. The fieldwork is a long-term collaboration by scientists from several institutions in Myanmar; as well as the University of Poitiers and the University of Montpellier in France; Carnegie Museum of Natural History in Pittsburgh, PA; and the Department of Mineral Resources in Bangkok, Thailand. Funding was provided by the U.S. National Science Foundation and the Centre National de la Recherche Scientifique in France.


Adapted from materials provided by Carnegie Museum of Natural History.
Source: http://www.sciencedaily.com/releases/2009/06/090630202125.htm

luglio 4, 2009 Posted by | 1 | , , | Lascia un commento

2009-03-13 – Evoluzione: I denti del pesce “Dracula” (evolution, “Dracula” fish)

SCOPERTO PESCE-DRACULA MISURA SOLO 16 MILLIMETRI

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• Per gli scienziati è straordinario
Ha due denti aguzzi come i canini di un vampiro il “Danionella Dracula”, un pesce un cui esemplare è stato scoperto in un fiume in Birmania. Il pesce, piccolissimo – misura poco più di 16 millimetri di lunghezza – è stato trovato vicino Mogaung, nel Myanmar, e gli scienziati hanno subito definito la scoperta “straordinaria”. “E’ una delle creature più interessanti scoperte negli ultimi decenni”, hanno detto al quotidiano britannico “Telegraph”. I denti aguzzi di cui è dotato il piccolo pesciolino, che altro non sono che un prolungamento della lisca, gli hanno regalato il soprannome, dal notissimo romanzo di Bram Stoker. Ralf Britz, zoologo al museo di storia naturale di Londra, ha detto: “Questo pesce è una delle scoperte più straordinarie degli ultimi cinquant’anni. I denti che il Danionella Dracula ha sono molto particolari, perché delle oltre 3700 specie di pesci di questo tipo, nessun esemplare aveva i denti. I loro antenati preistorici persero i loro denti più di 50 milioni di anni fa”. La squadra di ricerca di Britz sta già lavorando ad analizzare il piccolo pesce, alla St. Louis University del Missouri (Usa).

FONTE: http://www.leggonline.it/articolo.php?id=16197

 

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PHOTO IN THE NEWS: New “Dracula” Fish Discovered

2009-03-12-dracula-fish-01

March 11, 2009–While he may not vant to suck your blood, the male fish seen above does sport spooky-looking fangs that have earned it the name Danionella dracula.

Researchers at London’s Natural History Museum found several of the new species (bottom) in a tank of aquarium fish. Initially museum staff had thought the 0.7-inch-long (1.7-centimeter-long) creatures, caught in Myanmar (Burma), were part of an already known, related species.

“After a year or so in captivity, they started dying,” museum scientist Ralf Britz told BBC News.

“When I preserved them and looked at them under the microscope, I thought, my God, what is this, they can’t be teeth.”

In fact, the fangs are not true teeth—the line of fish that gave rise to D. dracula is thought to have lost teeth around 50 million years ago.

By staining the bone and dissolving away tissue to reveal the full jawbones of dead specimens (top), Briz found that the odd species has rows of bony jaw protrusions (inset) that lack the pulp cavities and enamel caps of true teeth.

Despite their ghoulish appearance, the fangs likely aren’t used for feeding.

“We did not study stomach contents, but we know that its close relatives live on small crustaceans … and other small invertebrates,” Britz said in an email to National Geographic News. “In captivity it readily accepts brine shrimp [larvae], tiny nematodes, and even very fine flake food.”

Based on the behavior of live “Dracula” fish, the researchers think the males use their extralong fangs to spar with each other during aggressive displays. The findings are described this week in the online edition of the Proceedings of the Royal Society B.

—Victoria Jaggard

Photographs courtesy Ralf Britz, Natural History Museum

SOURCE: nationalgeographic.com

marzo 13, 2009 Posted by | - Pesci / Fishes, An. Vertebrates, Asia, Attuale, Bio-Zoology / Bio-Zoologia, Lang. - Italiano, P - Evoluzione | , , , , , , | Lascia un commento

2008-09-03 – In ambra il più antico geko fossile, Birmania, Cretaceo

Oldest Gecko Fossil Ever Found, Entombed In Amber

ScienceDaily (Sep. 3, 2008) — Scientists from Oregon State University and the Natural History Museum in London have announced the discovery of the oldest known fossil of a gecko, with body parts that are forever preserved in life-like form after 100 million years of being entombed in amber.

Due to the remarkable preservative power of being embalmed in amber, the tiny foot of this ancient lizard still shows the tiny “lamellae,” or sticky toe hairs, that to this day give modern geckos their unusual ability to cling to surfaces or run across a ceiling. Research programs around the world have tried to mimic this bizarre adhesive capability, with limited success.

This gecko’s running days are over, however, as only the foot, toes and part of a tail are left in the stone. The rest might have become lunch for a small dinosaur or other predator during an ancient fight in the tropical forests of Myanmar during the Lower Cretaceous Period, from 97 million to 110 million years ago.

The find is at least 40 million years older than the oldest known gecko fossil, shedding additional light on the evolution and history of these ancient lizards that scampered among the feet of giant dinosaurs then and still are common in tropical or sub-tropical regions all over the world.

The findings were just published in Zootaxa, a professional journal.

“It’s the unusual toe pads and clinging ability of some geckos that make them such a fascinating group of animals, so we were very fortunate to find such a well-preserved foot in this fossil specimen,” said George Poinar, Jr., a courtesy professor at OSU and one of the world’s leading experts on insects, plants and other life forms trapped in amber, a semi-precious stone that begins as tree sap.

“There’s a gecko society, gecko clubs, just a lot of interest in these animals because of their unusual characteristics,” Poinar said. “So there are a lot of people pretty excited about this.”

Based on the number of lamellae found on its toe pads, this gecko was probably a very small juvenile of what would have become a comparatively large adult, possibly up to a foot long, the researchers say. Modern geckos get no more than about 16 inches long, although it’s possible there were larger species millions of years ago. The juvenile gecko found in the fossiljuvenile gecko found in the fossil was less than an inch in length when it died – possibly by being eaten or attacked, since only partial remains were found.

The discovery has been announced as a new genus and species of gecko, now extinct, and has been named Cretaceogekko. It had a striped pattern that probably served as camouflage.

There are more than 1,200 species of geckos in the world today , common in warm or tropical regions, including parts of the southern United States. They are frequently kept as pets, and often are welcome in the homes of some tropical residents because they help control insects. Some are very colorful. They use long tongues to lick, clean and moisturize their eyes.

“Geckos are territorial, and when I lived in Africa in the early 1980s we used to have them in our house,” Poinar said. “They are pretty friendly and don’t bother humans. Certain individuals would move into the house, we’d give them names, and they would run around the house, catch mosquitoes, help control bugs. They would crawl across the ceiling and look down at you.”

The new study provides evidence that geckos were definitely in Asia by 100 million years ago, and had already evolved their bizarre foot structure at that time. The amber fossil was mined in the Hukawng Valley in Myanmar, and during its life the gecko probably lived in a moist, tropical forest with ample opportunities for climbing.

The ability of geckos to walk on vertical walls or even upside down is due to the presence of thousands of “setae” on their toes, very tiny, hairlike structures that have tips which attach to surfaces by van der Walls forces. It’s a type of incredibly strong, dry adhesion shared by virtually no other group of animals.

It’s not known exactly how old this group of animals is, and when they evolved their adhesive toe pads. However, the new study makes it clear that this ability was in place at least 100 million years ago, in nature. Modern research programs still have not been able to completely duplicate it.

Scientists at the University of California at Berkeley reported earlier this year that they have developed a new “anti-sliding” adhesive that they said was the closest man-made material yet to mimic the ability of geckos – they think it might help a robot climb up the side of walls. A research team at the Massachusetts Institute of Technology this year created a waterproof adhesive bandage inspired by geckos, that may some day be used in surgery. And of course, geckos have become an advertising icon for the insurance company Geico.

This study is just one of many in which Poinar and colleagues have used the unusual characteristics of amber to study ancient life forms and develop information on the ecology of ancient ecosystems.

As a stone that first begins to form as sap oozing from a tree, amber can trap small insects or other life forms and preserve them in near-perfect detail for observation millions of years later.

http://www.sciencedaily.com/releases/2008/09/080902163920.htm

other links:

http://news.nationalgeographic.com/news/2008/09/080903-gecko-amber.html

 

settembre 20, 2008 Posted by | - Rettili, Asia, P - Ambra, P - Preservazione eccezionale, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , | 2 commenti