Paleonews

Il blog dedicato ai Paleontologi !!!!

2009-07-05 – Indonesian elephant fossil

Indonesian elephant fossil opens window to past

By NINIEK KARMINI – Jun 22, 2009

Indonesia Prehistoric Elephant

Scientists arrange the bones of an estimated 200,000 year-old giant elephant at Geology Museum in Bandung, West Java, Indonesia, Thursday, June 18, 2009. Indonesian scientists are reconstructing the largest, most complete skeleton of an ancient elephant ever found in the tropics, a finding that may offer new clues into the largely mysterious origins of its modern Asian cousin. Based on the fossil, the ancient elephant stood four meters (13-feet) tall, was five meters (16-feet) long and weighed more than 10 tons, considerably larger than the great Asian mammals now on Earth. (AP Photo/Dita Alangkara)

 BANDUNG, Indonesia (AP) — Indonesian scientists are reconstructing the largest, most complete skeleton of a prehistoric giant elephant ever found in the tropics, a finding that may offer new clues into the largely mysterious origins of its modern Asian cousin.

The prehistoric elephant is believed to have been submerged in quicksand shortly after dying on a riverbed in Java around 200,000 years ago. Its bones — almost perfectly preserved — were discovered by chance in March when an old sand quarry collapsed during monsoon rains.

The animal stood four meters (13-feet) tall, five meters (16-feet) long and weighed more than 10 tons — closer in size to the woolly mammoth of the same period than to the great Asian mammals now on Earth.

Animal fossils are rare in the humid, hot climate of the equator because decomposition occurs extremely quickly.

Following a monthlong excavation, a team of seven paleontologists from the Geology Museum in Bandung, West Java, set the bones in plaster for the trip back to their office where they will be laboriously pieced back together.

“We believe from the shape of its teeth that it was a very primitive elephant,” but little else has been verified, said paleontologist Fachroel Aziz, who is heading a 12-strong skeletal reconstruction team.

Scientists agree it is the first time an entire prehistoric elephant skeleton has been unearthed since vertebrate fossil findings began to be recorded in Indonesia in 1863.

“It is very uncommon to discover a fossil like this in a tropical region like Indonesia,” said Edi Sunardi, an independent expert at Indonesia’s Pajajaran University in Bandung, West Java. “It apparently was covered by volcanic sediment that protected it from high temperatures, erosion and decay.”

The next challenge will be removing the delicate bones from their molds and joining them into a stable, upright structure, a process that experts said is already being hampered by a lack of funding, inadequate tools and poor expertise.

Indonesia, an emerging and impoverished democracy of 235 million people, cannot afford to allocate more than a token sum to its aging museums, even for projects that have the potential to advance knowledge about the origin of key native species.

Gert van den Berg, a researcher at Australia’s Wollongong University who helped dig up the skeleton, said tests are under way to determine its precise age and species, and that they will help provide details “about when the modern elephants evolved into what they are now.”

About 2,000 old elephant remains have been found across the island nation over the past 150 years, but never in such good condition, Aziz said.

“We want to exhibit it publicly because this is a spectacular discovery,” he said.

 The Associated Press

Annunci

luglio 5, 2009 Posted by | - Mammiferi, An. Vertebrates, Asia, Cenozoic, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , | Lascia un commento

2009-06-19 – Mongolia: Nuovo Psittacosauro (new Psittacosaur)

Parrot-like dinosaur found in Mongolia

A new dinosaur resembling a giant parrot has been discovered in Mongolia.

 By Chris Irvine
Published: 7:00AM BST 17 Jun 2009
New dinosaur, Psittacosaurus gobiensis: Parrot-like dinosaur found in Mongolia
A new dinosaur, named Psittacosaurus gobiensis, meaning ‘parrot dinosaur’ has been discovered in Mongolia

The creature, Psittacosaurus gobiensis whose name means “parrot lizard”, is thought to have lived about 110 million years ago.

Psittacosaurs are noted for being the most species-rich dinosaur genus with at least nine different species, including the latest found in the Gobi Desert, a famous dinosaur graveyard.

Features of the dinosaur included a near perfect skull, strong jaw muscles and a powerful biting and crushing bill – showing that it evolved structures like those in today’s parrots.

The three feet long psittacosaurs may also have had a diet dominated by nuts and seeds, owing to the presence of many large stomach stones, according to the findings published in Proceedings of the Royal Society B: Biological Sciences.

Prof Paul Sereno, a Biologist from the University of Chicago, said analysis of its skull showed it chewed its food in a similar way to modern parrots.

“These and other features, along with the presence of numerous large stomach stones, suggest that psittacosaurs may have had a high-fibre, nut eating diet,” he said.

Its short snout just a third of the skull length was different to most dinosaurs, giving the skull its parrot-esque profile.

They ate nothing but plants and walked normally on two legs but could reach the ground with their three-fingered hands.

They were good runners and were extremely successful in Asia about 100 million years ago, during the Cretaceous Period.

“Psittacosaurs are all relatively small in body size, ranging from one to two metres in body length. Their geographic range is limited to central Asia, and their temporal range may be as narrow as 10-20 million years in the mid Cretaceous,” said Prof Sereno.

It is a member of the Ceratopsia group of herbivorous, beaked dinosaurs, which also include the more famous Triceratops.

source: telegraph.co.uk

———————————

Other links: click here

giugno 19, 2009 Posted by | 1 Cretaceo, Articolo sc. di riferimento, Asia, Mesozoic, P - Preservazione eccezionale, P - Ritrovamenti fossili | , , , , | Lascia un commento

2009-06-18 – Limusaurus inextricabilis and the evolution of dinosaurs hands

per informazioni in italiano vedi:

BLOG THEROPODA – Limusaurus inextricabilis Xu et al. (2009) – Prima Parte: Un Ceratosauria senza denti dal Giurassico Superiore della Cina!

————————————– 

New dinosaur gives bird wing clue

Limusarus fossil (James Clark)
The Limusaurus fossil sits among small crocodile fossils

A new dinosaur unearthed in western China has shed light on the evolution from dinosaur hands to the wing bones in today’s birds.

The fossil, from about 160 million years ago, has been named Limusaurus inextricabilis.

The find contributes to a debate over how an ancestral hand with five digits evolved to one with three in birds.

The work, published in Nature, suggests that the middle three digits, rather than the “thumb” and first two, remain.

Theropods – the group of dinosaurs ancestral to modern birds and which include the fearsome Tyrannosaurus rex – are known for having hands and feet with just three digits.

It’s a really weird animal – it’s got no teeth, had a beak and a very long neck, and very wimpy forelimbs
James Clark, GWU

It has been a matter of debate how the three-fingered hand developed from its five-fingered ancestor. Each digit among the five was composed of a specific number of bones, or phalanges.

Palaeontologists have long argued that it is the first (corresponding to the thumb), second, and third fingers from that ancestral hand that survived through to modern birds, on grounds that the three fingers in later animals exhibit the correct number of phalanges.

However, developmental biologists have shown that bird embryos show growth of all five digits, but it is the first and fifth that later stop growing and are reabsorbed.

The remaining three bones fuse and form a vestigial “hand” hidden in the middle of a bird’s wing.

‘Weird animal’

James Clark of George Washington University in Washington DC and Xing Xu from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing hit an palaeontologist’s gold mine in the Junggar Basin of northwestern China.

Previous digs have unearthed the oldest known fossil belonging to the tyrannosaur group and the oldest horned dinosaur among several others.

Limusarus fossil (Portia Sloan)
The dinosaurs had beaks and may have had feathers

This time, the ancient mire has yielded a primitive ceratosaur, a theropod that often had horns or crests, many of whom had knobbly fingers without claws.

“It’s a really weird animal – it’s got no teeth, had a beak and a very long neck, and very wimpy forelimbs,” Professor Clark told BBC News.

“Then when we looked closely at the hand, we noticed it was relevant to a very big question in palaeontology.”

The fossil has a first finger which is barely present, made up of just one small bone near the wrist. The fifth finger is gone altogether.

It is a fossil that appears to offer a snapshot of evolution, proving that the more modern three-fingered hand is made up of the middle digits of the ancestral hand, with the outer two being shed.

The third finger is made up of the four phalange bones that the second should have, and it is presumed that the second would lose one bone to become like the first finger that was missing in the fossil.

This process of shifting patterns of gene expression from one limb or digit to another is known as an “identity shift”, and was again caught in the act – making the conflicting theories of bird hand origin suddenly align.

“This is amazing – it’s the first time we’ve seen this thing actually starting to disappear,” Jack Conrad, a palaeontologist at the American Museum of Natural History, told BBC News.

“There’s been this fundamental rift – there was no way to make peace between the good data we were seeing from the developmental biologists and the palaeontological evidence that showed with every fossil we found we were seeing [fingers] one, two and three.”

from: http://news.bbc.co.uk/1/hi/sci/tech/8105513.stm

——————————————————————

Other links:

Fossil Solves Mystery of Dinosaur Finger Evolution

FOXNews – ‎17/giu/2009‎

By Jeanna Bryner Bird wings clearly share ancestry with dinosaur “hands” or forelimbs. A school kid can see it in the bones.

Fossil Catches Dinosaur Red-Handed, Evolving Into Bird Wired News

NEW DINOSAUR: Fossil Fingers Solve Bird Wing Mystery? National Geographic

giugno 18, 2009 Posted by | - R. Dinosauri, - Teropodi, An. Vertebrates, Articolo sc. di riferimento, Asia, Italiano (riassunto), P - Evoluzione, P - Ritrovamenti fossili, Paleontology / Paleontologia, X - Nature | , | 1 commento

2009-04-28 – Chongqing, China: “China’s Prehistoric Animal Fossil Exhibition”

Prehistoric “dinosaur”, “mammoth” fossils displayed in Chongqing 

 see the video
 
www.chinaview.cn 2009-04-27 21:49:04

BEIJING, April 27 — A herd of animals led by two “mammoths” and nine “dinosaurs” are causing a stir in the central Chinese city of Chongqing.

    “China’s Prehistoric Animal Fossil Exhibition” is underway at the city’s Liberation Monument Square. More than 30 precious artifacts are on display.

    The show features relics from well-known museums in 8 provinces and cities. Many of the fossils are considered national treasures and date between the Jurassic and the Quatenary periods 190 million years ago.Among the highlights are the bones of nine dinosaurs and a well-preserved woolly mammoth skeleton. Researchers estimate the 2-and-a-half-meter-tall mammoth is about three million years old. A nearby mechanical replica mimics the movements and sound of the real thing.This exhibition runs until May 24th.

    Xinhua News Agency correspondents reporting from Chongqing.

    (Source: XHTV)

 
Editor: Bi Mingxin

aprile 28, 2009 Posted by | - Mammiferi, - R. Dinosauri, An. Vertebrates, Asia, Mostre & Fiere, Paleontology / Paleontologia, Places | , , , , , , , , , , | Lascia un commento

2009-04-24 – Antenato del T.rex & co. (Tyrannosaurus rex ancestor, Xiongguanlong baimoensis & Ornithomimid, Beishanlong grandis)

Ancestor of T rex found in China

Tyrannosaur model, ADRIAN DENNIS/AFP/Getty Images
Tyrannosaurus rex may have had much smaller ancestors

 

Fossils found in China may give clues to the evolution of Tyrannosaurus rex.

Uncovered near the city of Jiayuguan, the fossil finds come from a novel tyrannosaur dubbed Xiongguanlong baimoensis.

The fossils date from the middle of the Cretaceous period, and may be a “missing link”, tying the familiar big T rex to its much smaller ancestors.

The fossils show early signs of the features that became pronounced with later tyrannosaurs.

Paleontological knowledge about the family of dinosaurs known as tyrannosaurs is based around two distinct groups of fossils from different parts of the Cretaceous period, which ran from approximately 145 to 65 million years ago.

One group dates from an early part of the period, the Barremian, and the other is from tens of millions of years later.

Physical form

Before now it has been hard for palaeontologists to trace the lineage from one group to the other.

“We’ve got a 40-50 million year gap in which we have very little fossil record,” said Peter Makovicky, associate curator at the Field Museum in Chicago, who helped to lead the US/Chinese team that uncovered the fossil.

 

Velafrons coahuilensis
Hadrosaurs – duck-billed dinosaurs – spread rapidly in the late Cretaceous

But, he said, X baimoensis was a “nice link” between those two groups.

“We’re filling in that part of the fossil record,” he said.

Writing in the Royal Society’s journal Proceedings B, Dr Makovicky and colleagues suggest that X baimoensis is a “phylogenetic, morphological, and temporal link” between the two distinct groups of tyrannosaurs.

The fossil has some hallmarks of large tyrannosaurs such as a boxy skull, reinforced temple bones to support large jaw muscles, modified front nipping teeth and a stronger spine to support a large head.

But it also shows features absent from older tyrannosaurs, such as a long thin snout.

An adult would have stood about 1.5m tall at the hip and weighed about 270kg. By contrast, an adult T rex was about 4m tall at the hip and weighed more than 5 tonnes.

Wider net

The same edition of Proceedings B features papers about two other sets of dinosaur fossils.

One discovery was made in China by many of the palaeontologists who found the tyrannosaur. The samples found in the Yujingzi Basin came from a dinosaur that resembled the modern ostrich.

While many of these ornithomimosaurs have been found before, analysis of the bones of the new species, dubbed Beishanlong grandis, suggest it was one of the biggest.

The specimen found by the palaeontologists was thought to be 6m tall and weigh about 626kg.

Alongside in Proceedings B was work on the remains of a duck-billed dinosaur found in Uzbekistan called Levnesovia transoxiana.

Analysis of the fossils, by Hans-Dieter Sues of the Smithsonian in Washington and Alexander Averianov of the Russian Academy of Sciences, may shed light on the waves of expansion hadrosaurs undertook during the late Cretaceous.

————————————————-

T. Rex Relative Fills Evolutionary Gap

FOXNews – ‎22-apr-2009‎
A Tyrannosaurus rex ancestor and an ostrich-mimic have emerged as two new dinosaur species found among a treasure trove of skeletons in China’s Gobi Desert.
T-Rex ancestor discovered DigitalJournal.com

aprile 24, 2009 Posted by | - R. Dinosauri, 1 Cretaceo, An. Vertebrates, Articolo sc. di riferimento, Asia, Mesozoic, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , | Lascia un commento

2009-03-17 – Trappola mortale per i piccoli dinosauri (Sinornithomimus herd)

Sulla rivista “Acta Palaeontologica Polonica”

Trappola mortale per i piccoli dinosauri

I resti suggeriscono che gli individui ancora immaturi venissero lasciati badare a loro stessi mentre gli adulti erano occupati nella costruzione del nido o nella cova delle uova

Un branco di giovani dinosauri simili a uccelli hanno trovato la morte nei fangosi margini di un lago circa 90 milioni di anni fa, secondo quanto annunciato da un gruppo di paleontologi cinesi e statunitensi che hanno scavato in un sito del Deserto del Gobi, nella parte occidentale della Mongolia interna.

L’improvvisa morte degli animali in una trappola di fango fornisce una rara istantanea del loro comportamento sociale. Composto soltanto da esemplari giovani di una singola specie di dinosauri ornitomimidi (Sinornithomimus dongi), il branco suggerisce che gli individui ancora immaturi venissero lasciati badare a loro stessi mentre gli adulti erano occupati nella costruzione de nido o nella cova delle uova.

“Non c’erano adulti intorno, questi cuccioli scorrazzavano da soli”, ha spiegato Paul Sereno, professore dell’Università di Chicago ed esploratore del National Geographic e coautore dell’articolo apparso sulla rivista “Acta Palaeontologica Polonica”.

Le prime ossa vennero scoperte da un geologo cinese nel 1978 alla base di una piccola collina in una desola regione del Deserto del Gobi e circa 20 anni fa un gruppo sino-giapponese estrasse i primi scheletri, battezzando il dinosauro Sinornithomimus (“che somiglia a un uccello cinese”).

Sereno e colleghi hanno seguito lo scavo di uno scheletro dopo l’altro fino a penetrare in profondità nella base della collina. Complessivamente, sono stati estratti 25 individui di età compresa tra uno e sette anni, come determinato dagli anelli di crescita annuale delle loro ossa.

Il gruppo ha poi registrato in meticolosamente la posizione di tutte le ossa e i dettagli degli strati di roccia per cercare di comprendere in che modo cosi tanti individui di una stessa specie siano periti nello stesso luogo. Gli scheletri mostrano un ottimo stato di conservazione e il fatto che siano tutti nella stessa direzione fa supporre che siano morti anche entro un arco temporale molto breve.

I dettagli forniscono le prove di una piccola tragedia. “Gli animali hanno subito una morte lenta in una trappola di fango, e la loro agitazione è servita solo ad attrarre predatori o animali che si nutrivano di carogne”, ha concluso Sereno. Di solito gli eventi atmosferici, l’azione di altri animali o il trasporto di ossa cancellano qualunque prova diretta delle cause di morte. Perciò questo sito è unico per ricchezza di dettagli sugli animali e sulla loro morte.” (fc)

fonte: lescienze

————————————–

Photo: “Teen” Dinosaurs Roamed in Herds, Mass Grave Suggests

Young Sinornithomimus dinosaurs may have wandered in packs (illustrated at top), fending for themselves while adults were busy nesting, according to a recent report.
Two juvenile Sinornithomimus skeletons (photo at bottom) died when they were a little over one year old. In their rib cages are stomach stones and the carbonized remains of the last plants they consumed.

Illustration by Todd Marshall, courtesy Project Exploration; photograph by Mike Hettwer, courtesy Project Exploration

Illustration by Todd Marshall, courtesy Project Exploration; photograph by Mike Hettwer, courtesy Project Exploration

————————————–

MSU paleontologist authors paper on social behavior among adolescent dinosaurs

March 16, 2009 — By Michael Becker, MSU News Service

BOZEMAN — A Montana State University researcher is the lead author of a recently published paper that sheds new light on the behaviors of dinosaur families and gives a rare glimpse into the social life — and death — of a herd of dinosaurs.
David Varricchio, an assistant professor and paleontologist in the Department of Earth Sciences, and colleagues from the University of Chicago and China wrote the paper after a 2001 expedition to the Gobi Desert. It was published in December in the journal Acta Palaeontologica Polonica.
The paper describes the team’s work at a 90-million-year-old dry lake bed in western Mongolia. Over the past decade, paleontologists have recovered more than two dozen fossilized skeletons of the dinosaur Sinornithomimus.
All of the skeletons belonged to animals between one and seven years old and were well-preserved. Most of skeletons were facing the same direction, suggesting that they died together in a short period of time, Varricchio said.
“Normally there are a lot of post-mortem effects that transpire between when a dinosaur died and when it was buried,” he said. “This site really provides, in my mind, better evidence than any other dinosaur locality of how the dinosaurs perished, and that’s pretty rare for any fossil vertebrate.”

Varricchio believes that the dinosaurs probably became mired in the mud around a partially dry lakebed during the Cretaceous Period. During times of drought, as were common in the region at the time, these oases likely attracted many animals, he said.

Many of those animals were probably weak from starvation and dehydration, which could explain why so many of them became trapped in the mud. It’s a phenomenon that’s still seen around dry desert lakes today, he said.

The fact that so many young dinosaurs of the same species died at roughly the same time and in the same place tells paleontologists something about the social behavior of the animals, Varricchio said. It may be that young dinosaurs — too old for the nest but not yet old enough to fend for themselves — roamed together in social herds, he said.

“We get a snapshot-like view of what a herd of these animals looked like back in the Cretaceous Period,” Varricchio said. “That snapshot gives us a glimpse into their biology and their behavior.”

Past studies have theorized that dinosaurs had strong and complicated parenting relationships with their young, Varricchio said. Female — and even male — dinosaurs were tied to a nesting spot for the breeding portions of the year while they took care of their eggs, he said.

The fact that the parent dinosaurs were busy with the eggs could explain why a group of adolescent dinosaurs was roaming together without adult supervision, Varricchio said. These and most dinosaurs would take several years, at least, to fully mature. Groups of juveniles would consist of those individuals too old to be cared for by parents, but too young to breed, he said.

“This site argues that this might be a general trend among dinosaurs,” and is further evidence of the theory that dinosaurs were dedicated parents, he said.

Varricchio’s collaborators include Paul Sereno from the University of Chicago, Tan Lin from he Department of Land and Resources of Inner Mongolia and Zhao Xijin from the Chinese Academy of Sciences. Also on the team were Jeffrey Wilson from the University of Michigan and Gabrielle Lyon from Project Exploration.

The work was funded by the National Geographic Society and the David and Lucile Packard Foundation.

 

 

 

 

Contact: David Varricchio at 406-994-6907 or djv@montana.edu.
 
 Hi-Resolution Image or PDF Available:
[View or Download] 1. MSU’s David Varricchio examines fossils in his laboratory in the basement of Traphagen Hall. (MSU photo by Kelly Gorham)

source: http://www.montana.edu/cpa/news/nwview.php?article=6951

————————————————————————

Teen dinosaurs hung out, got into trouble

MSNBC – ‎17 ore fa‎
Like teenagers today, some juvenile dinosaurs used to hang out together, according to research announced today. Also like teens, the dinos sometimes hung
Boston Globe

 

Frozen in time: Dinosaur herd’s mass grave unearthed

ABC Online – ‎5 ore fa‎
In the rocky desert of Inner Mongolia, an international team of palaeontologists has unearthed a mass grave of young dinosaurs. The 25 birdlike dinosaurs
Montana State University

marzo 17, 2009 Posted by | - R. Dinosauri, - Teropodi, 1 Cretaceo, An. Vertebrates, Asia, Bl - Top posts, Mesozoic, P - Paleoetologia, P - Preservazione eccezionale, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , | Lascia un commento

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

SCOPERTO PESCE-DRACULA MISURA SOLO 16 MILLIMETRI

PD*27442385

• 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

 

—————————————————————————

 

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

2009-03-11 – “Uomo di Pechino” più vecchio di quanto si pensava (oldest Peking Man)

Evoluzione: l’uomo di Pechino più vecchio di 200mila anni

Virgilio Notizie – ‎16 ore fa‎
(Apcom) – Una nuova analisi fatta sulle ossa fossili dell’Homo erectus di Zhoukoudian, meglio noto come l’uomo di Pechino, rivela che questo reperto

—————————————————————

‘Peking Man’ older than thought

—————————————————————–

About the cover

Nature.com (subscription) – ‎3 ore fa‎
The age of Homo erectus, known familiarly as Peking Man, has been hotly debated. This week Shen et al. use a recently developed dating technique that

News and Views

Nature.com (subscription) – ‎3 ore fa‎
Re-evaluation of the age of Zhoukoudian, a prominent site of Homo erectus occupation in China, prompts a rethink of the species’ distribution in both the

Age of Zhoukoudian Homo erectus determined with 26 Al/ 10 Be

Nature.com (subscription) – ‎3 ore fa‎
The age of Zhoukoudian Homo erectus, commonly known as ‘Peking Man’, has long been pursued, but has remained problematic owing to the lack of suitable

Ancient ‘Peking Man’ way older than thought

MSNBC – ‎2 ore fa‎
After the first fossil was found, anthropologists eventually turned up skulls and bones representing at least 40 H. erectus individuals, other mammal
AFP
By Paul Rincon
Science reporter, BBC News


Zhoukoudian (Dr. Gao Xing, Institute of Vertebrate Palaeotology and Palaeoanthropology)
The Zhoukoudian caves have yielded many fossils of Homo erectus

Iconic ancient human fossils from China are 200,000 years older than had previously been thought, a study shows.

The new dating analysis suggests the “Peking Man” fossils, unearthed in the caves of Zhoukoudian are some 750,000 years old.

The discovery should help define a more accurate timeline for early humans arriving in North-East Asia.

A US-Chinese team of researchers has published its findings in the prestigious journal Nature.

The cave system of Zhoukoudian, near Beijing, is one of the most important Palaeolithic sites in the world.

Between 1921 and 1966, archaeologists working at the site unearthed tens of thousands of stone tools and hundreds of fragmentary remains from about 40 early humans.

Palaeontologists later assigned these members of the human lineage to the species Homo erectus.

The pre-war Peking Man fossils vanished in 1941 whilst being transported to the US for safekeeping. Luckily, the palaeontologist Franz Weidenreich had made casts for researchers to study.

Experts have tried various methods over the years to determine the age of the remains. But they have been hampered by the lack of suitable techniques for dating cave deposits such as those at Zhoukoudian.

Open habitats

Now, Guanjun Shen, from Nanjing Normal University in China, and colleagues have applied a relatively new method to the problem.

This method is based on the radioactive decay of unstable forms, or isotopes, of the elements aluminium and beryllium in quartz grains. This enabled them to get a more precise age for the fossils.

The results show the Peking Man fossils came from ground layers that were 680,000-780,000 years old, making them about 200,000 years older than had previously been believed.

Comparisons with other sites show that Homo erectus survived successive warm and cold periods in northern Asia.

Researchers Russell Ciochon and E Arthur Bettis III, from the University of Iowa, US, believe these climatic cycles may have caused the expansion of open habitats, such as grasslands and steppe. These environments would have been rich in mammals that could have been hunted or scavenged by early humans.

Recent revised dates for other hominid occupation sites in North-East Asia show that human habitation of the region began about 1.3 million years ago. The Nature study forms an important addition to this work.

The Peking Man fossils are a vital component of the Out of Africa 1 migration theory, which proposes that Homo erectus first appeared in Africa around two million years ago before spreading north and east (modern humans, Homo sapiens, would follow much later and supplant all other Homo species).

Evidence of the first dispersal comes from the site of Dmanisi in Georgia, where numerous hominid fossils dating to 1.75 million years ago have been unearthed. Finds from Java suggest early humans reached South-East Asia by 1.6 million years ago.

The northern populations represented at Zhoukoudian were probably separated from southern populations represented on the island of Java by a zone of sub-tropical forest inhabited by the giant panda, orangutans, gibbons and a giant ape called Gigantopithecus.

These early humans may have survived in island South-East Asia until 50,000 years ago.

Recent discoveries suggest that on the Indonesian island of Flores, Homo erectus, or another early human species, became isolated and evolved into a dwarf species called Homo floresiensis, nicknamed “The Hobbit”.

It is not clear whether H. erectus ever reached Europe; the earliest European fossils have been assigned to the species Homo antecessor. But this classification is disputed, and some researchers believe the Spanish antecessor fossils do indeed belong with H. erectus.

source: http://news.bbc.co.uk/1/hi/sci/tech/7937351.stm

marzo 11, 2009 Posted by | - Mammiferi, - Ominidi, - Primati, An. Vertebrates, Asia, Cenozoic, P - Paleoantropologia, Paleontology / Paleontologia, X - Nature, X - Riviste e Multimedia | Lascia un commento

2009-02-07 – Tra i fossili più antichi: Spugne (precambrian fossil sponges)

Antichissime impronte rinvenute nel precambriano dell’arabia Saudita sono state riconosciute come impronte di spugne. La scoperta ha ovviamente importantissime implicazioni di carattere ia tassonomico che soprattutto paleobiologico ed evoluzionistico

——————-

Ancient sponges leave their mark

By Jonathan Amos
Science reporter, BBC News

Rocks in Oman
The rocks date to a time of dramatic gaciation on Earth

Traces of animal life have been found in rocks dating back 635 million years.

The evidence takes the form of chemical markers that are highly distinctive of sponges when they die and their bodies break down in rock-forming sediments.

The discovery in Oman pushes back the earliest accepted date for animal life on Earth by tens of millions of years.

Scientists tell Nature magazine that the creatures’ existence will help them understand better what the planet looked like all that time ago.

“The fact that we can detect these signals shows that sponges were ecologically important on the seafloor at that time,” said lead author Gordon Love, from the University of California, Riverside.

“We’re not saying we captured the first animal; we’re saying they’re an early animal phylum and we’re capturing them when their biomass was significant.”

Tiny creatures

Researchers can usually determine the presence of ancient life in rock strata by looking for the fossilised remains of skeletons or the hardened record of the creatures’ movements, such as their footprints or crawl marks.

Sponges
Sponges are among the simplest multi-celled organisms

But for organisms deep in geological history that were extremely small and soft bodied, scientists have had to develop novel techniques to uncover their existence.

One of these newer methods involves detecting breakdown products from the lipid molecules which act as important structural components in the cell membranes of animals.

Over time, these will transform to leave a molecule known as cholestrane; and for sponges, this exclusively takes the form known as 24-isopropylcholestane.

Dr Love’s team found high concentrations of this biomarker in rocks located at the south-eastern edge of the Arabian peninsula.

They were laid down in what would have been a shallow marine environment at least 635 million years ago.

“Even though there must have been sufficient oxygen in the water to maintain the metabolism of these primitive animals, I think their size would have been restricted by oxygen being nowhere near modern values,” the UC Riverside researcher said.

“We’re probably talking about small colonies of sponges with body dimensions of a few millimetres at most. They’d have been filtering organic detritus in the water column.”

Icy planet

The discovery is fascinating because it pre-dates the end of the Marinoan glaciation, a deep freeze in Earth history that some argue shrouded the entire planet in ice.

Scientists often refer to the term “snowball Earth” to describe conditions at this time.

So to find animal life apparently thriving during this glaciation seems remarkable, commented Jochen Brochs, from the Australian National University, Canberra.

“If there really was a snowball Earth, how did those sponges survive? The full snowball Earth hypothesis would predict that the oceans were frozen over by 2km, even at the equator,” he told BBC News.

“Only at hot springs could any organism survive but it is questionable that you would have sponges in a hot spring. I haven’t made my mind up about snowball Earth but perhaps these sponges are telling us something about this glaciation.”

Dr Love’s view is that the presence of these animals puts limits on the scale of the ice coverage.

“I believe there were areas of what we might call refugia – areas of open ocean where biology could go on. And in this case, it could be evidence that we had some sort of evolutionary stimulation of new grades of organisms as well.”

Jonathan.Amos-INTERNET@bbc.co.uk

 

http://news.bbc.co.uk/2/hi/science/nature/7871099.stm

febbraio 7, 2009 Posted by | An. Invertebrates, Articolo sc. di riferimento, Asia, Bl - Top posts, Italiano (riassunto), P - Preservazione eccezionale, P - Ritrovamenti fossili, Paleontology / Paleontologia, Precambriano, X - Nature | , , , , , , , | Lascia un commento

2009-02-05 – Maiacetus inuus (Archaeoceti) e l’origine delle balene (whales origin)

Antiche balene di terra

Scoperti fossili di un antenato delle odierne balene che conduceva parte della vita in terra e parte in acqua

Due nuovi fossili di antiche balene – una femmina gravida e un maschio – gettano luce sul modo in cui gli antenati di questi giganteschi mammiferi sono passati da una vita terricola a quella acquatica.

I fossili risalgono a 47,5 milioni di anni fa e sono stati scoperti in Pakistan fra il 2000 e il 2004 per essere quindi studiati da paleontologi dell’Università del Michigan, che ora illustrano i loro risultati in un articolo pubblicato sulla rivista on line PloS.

Rispetto agli altri fossili di balena, quelli esaminati da Philip Gingerich e collaboratori – appartenenti alla specie Maiacetus inuus, facente parte del gruppo degli Archaeoceti – occupano una posizione intermedia sul cammino evolutivo che le ha portate a passare dall’essere animali completamente terricoli a marini.

L’eccezionalità del ritrovamento è dovuto anche al fatto che è la prima volta che si trova lo scheletro completo del feto di uno di questi animali. Il feto è posizionato in posizione cefalica, come i mammiferi terrestri e a differenza delle attuali balene, e ciò indica – osservano i ricercatori – che queste antiche balene partorivano sulla terraferma e non in mare. Un altro indizio dello stile di vita terricolo di questi animali è dato dal gruppo di denti ben sviluppati chiaramente individuabili nel fossile del feto, che indicano la capacità del piccolo di iniziare ad alimentarsi da solo.

Maiacetus aveva quattro zampe modificate in modo da poter nuotare abbastanza agevolmente. Peraltro, per quanto i loro arti modificati fossero in grado di sopportare il peso del corpo anche sulla terra, con molta probabilità non mettevano in grado l’animale di percorrere distanze di una certa entità. “Chiaramente vivevano nella zona compresa fra l’acqua e la terra andando su e giù”, ha osservato Gingerich.

Da altri indizi anatomici, fra cui la differenza di lunghezza dei canini fra maschio e femmina, i ricercatori hanno anche potuto ipotizzare, sulla scorta di un raffronto con i comportamenti delle diverse specie attualmente viventi, che i maschi non avessero una comportamento territoriale né che fossero a capo di un branco di femmine.  (gg)

http://lescienze.espresso.repubblica.it/articolo/Antiche_balene_di_terra/1334701

 ————————————————————————————-

Pregnant fossil shows how early whales evolved

Wed Feb 4, 2009 1:33am GMT

CHICAGO (Reuters) – Fossils from two early whales — a male and a rare pregnant female — shed light on how these ancestors to modern whales made the leap from walking on land to ruling the sea.

 The fetal remains, found with the 47.5 million-year-old pregnant female, were positioned head down, suggesting these creatures gave birth on land, while spending much of the rest of their time in the water.

 Initially, the tiny fetal teeth stumped University of Michigan paleontologist Philip Gingerich, whose team discovered the fossils in Pakistan in 2000 and 2004.

 “When I first saw the small teeth in the field, I thought we were dealing with a small adult whale, but then we continued to expose the specimen and found ribs that seemed too large to go with those teeth,” Gingerich, whose study appears in the Public Library of Science journal PLoS ONE.

 The fetal skeleton is the first specimen of the extinct whale group known as Archaeoceti, and the find represents a new species named Maiacetus inuus, a hybrid of the words for “mother whale” and Inuus, the name of a Roman fertility god.

 The fetus was positioned head down like other land animals, allowing it to begin breathing right away. This suggests the group had not yet made the leap to giving birth in the water like modern whales, which are born tail first to allow them to start swimming right after birth.

 The 8.5-foot (2.59-meter) male, which was collected in the same fossil beds as the female, is about 12 percent bigger and had fangs that were 20 percent larger than those of the female. Gingerich said these well developed choppers suggest the creatures spent a large portion of their time catching and eating fish.

 Both fossils had four flipper-like legs that could have supported their weight on land, but only for short distances, suggesting these whales likely came on shore to mate, rest and give birth, Gingerich said.

 “They clearly were tied to shore,” Gingerich said. “They were living at the land-sea interface and going back and forth.”

He said the Maiacetus fossils appear to represent an intermediate whale form, showing the evolution from land-dwelling to aquatic creatures.

 The full study can be found here

 (Editing by Sandra Maler)

http://uk.reuters.com/article/scienceNewsMolt/idUKTRE5130CQ20090204?pageNumber=2&virtualBrandChannel=0

 


Science Centric

Pregnant fossil shows how early whales evolved
Reuters – 22 ore fa
The 8.5-foot (2.59-meter) male, which was collected in the same fossil beds as the female, is about 12 percent bigger and had fangs that were 20 percent larger than those of the female.
Fossil shows whales lived on land Times Online
Earliest whales gave birth on land Science News
National Geographic – ScienceBlogs – Discover Magazine – dBTechno
e altri 83 articoli simili »

febbraio 5, 2009 Posted by | - Mammiferi, An. Vertebrates, Articolo sc. di riferimento, Asia, Cenozoic, FREE ACCESS, Lang. - Italiano, P - Evoluzione, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , | Lascia un commento