Paleonews

Il blog dedicato ai Paleontologi !!!!

2009-07-13 – New Theropod: Kemkemia auditorei (Cau & Maganuco, 2009)

Congratuazioni agli autori !!!

Ecco i post sul blog Theropda (A.Cau):

Annunci

luglio 13, 2009 Posted by | - R. Dinosauri, - Teropodi, 1 Cretaceo, Africa, An. Vertebrates, Articolo sc. di riferimento, Blogs, Lang. - Italiano, P - Ritrovamenti fossili, Paleontology / Paleontologia, Theropoda | , , , , , | Lascia un commento

2009-03-02 – L’origine della “camminata moderna” (birth of human walking)

Paleontologia: scoperte le più antiche orme umane che rivelano camminata ‘modernà

MILANO – Scoperte in Kenya orme fossili umane risalenti a 1,5 milioni di anni fa: sono le seconde più antiche, ma le prime a rivelare una camminata ‘modernà. Le orme infatti appartengono a un Homo ergaster e rivelano un piede anatomicamente simile al nostro e, appunto, anche una camminata identica a quella dell’uomo moderno. La scoperta è di ricercatori della Rutgers State University of New Jersey e della Bournemouth University in Gran Bretagna, e si è conquistata la copertina di Science. (Agr)
fonte: http://www.instablog.org/ultime/41778.html – 27 Febbraio 2009, 12:22
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Researchers Uncover 1.5-Million-Year-Old Footprints

Discoverers glean clues about human predecessors from tracks left on an ancient river shore in Kenya

By Katherine Harmon

Freshly discovered trails of ancient footprints, left on what was once the muddy shores of a river near Ileret, Kenya, indicate that some 1.5 million years ago human ancestors walked in a manner similar to that of people today. The international team of researchers who analyzed the prints say that those who left them had feet that looked a lot like ours.

The prints were probably left by Homo ergaster, an earlier, larger version of the widespread Homo erectus, says David Braun, a lecturer in archeology at the University of Cape Town in South Africa and co-author of the study set to be published tomorrow in Science. This discovery “lets us know that they were probably just as efficient at walking upright as we are,” he says.

Previous research has shown that human ancestors were perfectly capable of getting around on their hind legs 3.5 million years ago—and perhaps even earlier. But Braun says these prints reveal, for the first time, a very modern foot with a parallel big toe—unlike an ape’s opposable digit that’s easily curled for grasping tree branches. Homo sapiens proper are said to have emerged about 200,000 years ago.

Footprints can tell scientists a lot about creatures that a skeleton cannot. From them, scientists can learn about the gait, weight distribution and even the approximate size of those who made them.  Braun says these prints were apparently made by pedestrians who stood just under five feet (1.5 meters) tall. A modern upright stride can indicate a lot about behavior, as well, says David Raichlen, an assistant professor of anthropology at the University of Arizona in Tucson, who cites long-distance walking and running as possible benefits of this adaptation.

“It really is a snapshot of time,” Braun says. The preserved area also shows a wealth of animal prints, which gives more precise information about what creatures shared the space and time. Exhumed fossils can yield info on general environments; footprints can provide a glimpse into life over days rather than millennia. “With the footprints,” Braun says, “we can almost certainly say these things lived in the same time as each other, which is unique.”

It is much rarer to find footprints than bones, because conditions must be perfect for tracks to be preserved, according to Braun. In this case, the tracks were made during a rainy season near an ancient river just before that river changed course and swept a protective layer of sand over them.

The last major set of footprints, discovered in 1978 in Laetoli, Tanzania, were dated to about 3.6 million years ago. But those revealed a more ancient foot and gait, and it is still debatable whether those who made them had a stride more akin to humans or to chimpanzees, says Raichlen, who has studied the Laetoli prints.

The Ileret tracks were digitally scanned using a laser technique developed by lead study author, Matthew Bennett, a geoarchaeologist at Bournemouth University in Poole, England. Raichlen says the find gives people a rare view of those that have trod before. “It’s important to think about what you’re really getting: a glimpse of behavior in the fossil record that you wouldn’t really get in any other way,” he says. The research reveals “a moment in time when individuals are walking around the landscape. It sort of fleshes out and brings them back to life, in a way.”

source: http://www.sciam.com/article.cfm?id=15-million-footprints-uncover

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Fossil Footprints Pick up Ancient Man’s Trail in Africa

ScienceMode – ‎1 ora fa‎
The anthropology world is all abuzz with a discovery in Africa that’s knocking scientists off their feet. It’s the finding of 1.5 million-year-old

marzo 2, 2009 Posted by | - Mammiferi, - Ominidi, - Primati, Africa, An. Vertebrates, Articolo sc. di riferimento, Bl - Top posts, Cenozoic, Lang. - Italiano, P - Impronte, P - Paleoantropologia, P - Ritrovamenti fossili, Paleontology / Paleontologia, X - Science | , , , , , , , , , | Lascia un commento

2008-12-17 – Sahara: nuovi resti di dinosauri (new dinosaurs)

 

Due dinosauri ritrovati nel Sahara

17 dicembre 2008
ROMA – Il dorso di un gigante rettile volante e il collo di un enorme dinosauro erbivoro sono stati recentemente ritrovati in Marocco. Il merito della scoperta è stato attribuito a due scienziati, uno inglese e l’altro irlanndese, che stavano setacciando il letto di un antico fiume prosciugato nel deserto del Sahara.

I due ricercatori hanno anche scoperto molte impronte di dinosauri ed alcuni fossili, tra i quali i resti di un coccodrillo di 18 metri e un pesce predatore. Non c’è da stupirsi, però, della presenza di resti di animali “acquatici”. Quando queste specie erano in vita, infatti, quella del Sahra era una zona prosperosa e ricca di laghi, fiumi e vegetazione. Gli scavi archeologici sono stati fatti non lontano dalla frontiera algerina, dove nel periodo Cretacico scorreva un fiume dall’ampiezza pari a quella del Danubio.

Il Dott. David Martill dell’ Università di Portsmouth ha dichiarato: “Questo sistema fluviale era pieno di pesci giganti, ognuno lungo tra i 2 e i 4 metri. Ogni cosa era enorme. Si potrebbe chiamare il fiume dei giganti”. Il ritrovamento più importante di questa spedizione, è stato il frammento di 40cm del dorso di uno pterosauro, un rettile volante che visse nel periodo dei dinosauri. Gli scienziati credono che la creatura avesse un’apertura alare di circa 6 metri e che fosse imparentato con una più grande specie esistente in Nord America.

L’altro osso ritrovato, si è ipotizzato che possa essere un frammento di gamba, forse un femore, di un dinosauro dal collo lungo. Se così dovesse essere, sarebbe quello del dinosauro più imponente mai ritrovato. Secondo Martill è un parente del brachiosauro, ma ha delle caratteristiche molto differenti. Il direttore della ricerca, Nizar Ibrahim, dell’Università di Dublino, soddisfato dell’impresa ha dichiarato: ” E’ meraviglioso pensare che milioni di anni fa il Sahara fosse un verde paradiso tropicale, dimora di dinosauri e coccodrilli, altro che il deserto che vediamo oggi”.
from: http://www.diregiovani.it/gw/producer/dettaglio.aspx?id_doc=16392

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New dinosaurs discovered by British scientists in Sahara desert

By David Derbyshire
Last updated at 3:33 PM on 17th December 2008

A prehistoric ‘river of the giants’ that was once home to gigantic fish, towering dinosaurs and 60 foot long crocodiles has been unearthed by British fossil hunters.

The river – as wide as the Danube – flowed across the Sahara desert 100 million years ago, surrounded by lush forests, waterways and lakes.

The site has yielded some of the most exciting African prehistoric finds in years – including the tip of a giant flying reptile’s beak and a limb bone from a 65 foot long plant-eating dinosaur. Both are thought to be new species.

Other finds include the remains of a crocodile the length of two double deckers, two inch long scales shed by an freshwater predatory fish, and teeth from a massive sawfish.

Rare dinosaur footprints were also found at the site, near the Algerian border in south-east Morocco.

One of the scientists, Dr David Martill, from the University of Portsmouth, said: ‘This river system was stuffed full of gigantic fishes, each 2 to 4 metres long.

‘Everything there was of a huge size. You could call it the ancient river of the giants.’

The 16 inch long beak tip belonged to a previously unknown pterosaur – a flying reptile that lived alongside the dinosaurs. Pterosaur vertebrae up to six inches long were also uncovered in the sandy rocks.

The scientists believe the creature had a wingspan of up to 20 feet and was a relative of an enormous North American species called Quetzalcoatlus, whose wings spanned nearly 50 feet.

Another major find was a three foot long bone from a giant sauropod – a plant eating dinosaur with a long neck and tail which stood on four legs.

The researchers suspect the bone is a fore-limb from a creature at least 65 feet long.

But there is an outside chance that it is the lower end of a thigh bone belonging to a dinosaur nearly 100 feet long – making it the biggest sauropod ever known.

Dr Martill said: ‘Most people have no idea how diverse sauropods were – I think nearly 100 have been described. There were lots of different families.

‘We think this one might be linked with brachiosaurus, but it is different. The bone we found has some unusual features – it’s unusually robust for a humerus. We’re 95 per cent confident that it is a humerus but if its part of a femur it would mean this creature was unimaginably enormous.

‘Plant eaters are uncommon in this deposit, extremely rare in this region and to find one this large is very exciting. It’s a major discovery.’

The finds are now being examined in detail by expedition leader Nizar Ibrahim, from University College Dublin, who is carrying out the work for his PhD.

He said: ‘It’s amazing to think that millions of years ago the Sahara was in fact a lush green tropical paradise, home to giant dinosaurs and crocodiles and nothing like the dusty desert we see today.

‘Even to a palaeontologist dealing in millions of years it gives one an overwhelming sense of deep time.’

He added: ‘Finding two specimens in one expedition is remarkable, especially as both might well represent completely new species.’

The team spent a month in the desert and travelled more than five thousand miles by Land Rover, battling sandstorms and floods.

Having discovered the giant sauropod bone they had to return to the nearest town to get more water and plaster to protect it, a trip which involved crossing flooded rivers in their Land Rover at night with water coming in through the doors.

It almost proved impossible to retrieve the heavy sauropod fossil, which had to be carried on a stretcher down the side of a mountain through pouring rain.

‘When we had managed to get the bone in the Land Rover, the extra weight meant we kept sinking in the sand dunes,’ said Dr Martill.

The team hopes to return to the region to search for more fossils in November.

Other links:


Times Online

Fossil-hunters battle Sahara storms to find dinosaur prize
Times Online – 16 dic 2008
The first fossil is the beak of a pterosaur, a giant flying reptile that lived about 100 million years ago. Such discoveries are unusual because pterosaur bones were light and fragile, to be adapted to flight, and few fossilised well.
Giant Dinosaur Fossil Found in Sahara Desert LiveScience.com
New dinosaurs discovered by British scientists in Sahara desert Mail on Sunday
Science Daily (press release) – NewsLite – Daily Mail
e altri 26 articoli simili »

dicembre 17, 2008 Posted by | - R. Dinosauri, Africa, P - Ritrovamenti fossili, Paleontology / Paleontologia | Lascia un commento

2008-11-15 – Etiopia – Homo erectus: ossa di bacino femminile (female pelvis)

Scoperto in Etiopia un bacino fossile appartenente a una femmina di Homo Erectus.

Il ritrovamento ha consentito ai ricercatori che hanno pubblicato l’articolo su Science di fare interessanti considerazioni di carattere antropologico (ad esempio sulle dimensioni del bambino alla nascita, o sul grado di socializzazzione della specie).

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Wide-hipped fossil changes picture of Homo erectus

Thu 13 Nov 2008, 20:09 GMT

By Maggie Fox, Health and Science Editor

WASHINGTON, Nov 13 (Reuters) – The fossil of a wide-hipped Homo erectus found in Ethiopia suggests females of the pre-human species swayed their hips as they walked and gave birth to relatively developed babies with big heads, researchers said on Thursday.

The finding transforms thinking about some early human ancestors and evolution and suggests that helpless babies came along relatively late in the human lineage.

“We could look at this pelvis and then, using a series of measurements, we can calculate … how big the baby’s head could be at birth,” said Scott Simpson, a paleontologist at Case Western Reserve University who worked on the study.

Writing in the journal Science, Simpson and colleagues said the size and shape of the 1.2 million-year-old pelvis indicates that H. erectus females had hips wider than those of modern human females and their infants were born with heads about 30 percent larger than previously calculated.

“What this means is the offspring were not as helpless as a modern human,” he said in a telephone interview.

“It is not coming out walking and talking. But it was probably capable of more advanced behavior at a younger age like grasping, like sitting up … than we would see in a modern human.”

An extended childhood is a particularly human characteristic. Helpless babies require intensive care, not only from the mothers but from an extended group, which may have spurred the development of human society and culture.

Homo erectus, Latin for “upright man,” arose in Africa 1.8 to 2 million years ago, migrating to Asia and Europe before becoming extinct about half a million years ago. Experts agree it was likely a direct ancestor of modern humans.

Scientists did not know much about what its body would have looked like until the discovery of “Turkana Boy,” an adolescent H. erectus whose bones were discovered in 1984.

His slim-hipped build led researchers to believe that H. erectus gave birth to small-headed babies that would have required a great deal of care in early life, much like modern human infants.

But Simpson said Turkana boy’s pelvis was damaged and the restoration of a near-complete female pelvis from Gona, Ethiopia, changes this picture.

“This H. erectus would have even wider hips (than modern women),” Simpson said.

One main difference between human males and females is hip width, which makes women sway as they walk and which allows men to run and walk more efficiently.

“The reason women do have that sway is their hips are a little further apart,” Simpson said. “She would have had a good one.” (Editing by Alan Elsner)

source: http://africa.reuters.com/wire/news/usnN13527961.html


afrol News

Discovery of 1.5 Million Year Old Fossil of Female Pelvis in
MarketWatch – 20 ore fa
GOSPORT, Ind., Nov 14, 2008 /PRNewswire-USNewswire via COMTEX/ — The Stone Age Institute announces an important new fossil of a Homo erectus female pelvis from approximately 1.3 million years ago. This fossil reveals important new information about
Could fossil adds key piece to human evolution? Salt Lake Tribune
1.3 million year old human fossil found in Ethiopia afrol News
New Scientist (subscription) – Reuters South Africa – RedOrbit – Deseret News
e altri 101 articoli simili »

novembre 15, 2008 Posted by | - Ominidi, - Primati, Africa, Articolo sc. di riferimento, Italiano (riassunto), P - Paleoantropologia, P - Ritrovamenti fossili, Paleontology / Paleontologia, X - Science, x Terziario | , , , , , | Lascia un commento

2008-10-24 – Gli Eterodontosauri e l’origine dell’erbivoria nei Dinosauri Ornitischi (Heterodontosaurs and the origin of erbivory in ornitischian dinosaurs)

La scoperta di un cranio di un giovane esemplare di Heterodontosaurus favorisce nuove considerazioni sulla dieta e sul percorso evolutivo di questo dinosauro.

Prima della scoperta, la presenza di una dentatura eteromorfa (e in particolare la presenza dei canini) aveva dato luogo a due considerazioni contrastanti; alcuni ritenevano che tale dentatura costituisse una prova di un alimentazione onnivora, altri invece che la presenza dei canini fosse propria soltanto dei maschi e rappresentasse quindi solo un carattere sessuale secondario (vedi l’esempio attuale dei Trichechi)

Ora la scoperta di un esemplare giovane con canini già ben sviluppati avvalora la tesi dell’onnivoria e pone il genere Hterodontosaurus coma una delle fasi di passaggio tra un antenato carnivoro e i successori ornitischi (triceratopi, adrosauri, anchilosauri) erbivori.

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One of world’s smallest dinosaurs ever discovered ate meat AND plants

By Daily Mail Reporter
Last updated at 10:33 AM on 24th October 2008

[Photo: Laura Porro with her amazing find. The skull of a Heterodontosaurus had lain in a drawer since the 1960s]

One of the world’s smallest dinosaur skulls has been discovered, which could help explain how plant eaters branched off from their carnivorous cousins.

The tiny skull belongs to a young Heterodontosaurus, which lived 190million years ago, according to British and U.S researchers.

The mini dinosaur, which weighed around the same as an MP3 players, had fang-like canine teeth at the front for biting and tearing and flat grinding teeth typical of herbivores at the back.

‘Since Heterodontosaurs are among the earliest dinosaurs adapted to eating plants, they may represent a transition phase between meat-eating ancestors and more sophisticated, fully herbivorous descendants,’ Laura Porro from the University of Chicago said.

 ‘This juvenile skull indicates that these dinosaurs were still in the midst of that transition.’

 Porro came across the skull in a drawer in the Iziko South African Museum in Cape Town, while researching the eating habits of the Heterodontosaurs. ‘

‘I didn’t recognise it as a dinosaur at first,’ she said.

‘But when I turned it over and saw the eye looking straight at me, I knew exactly what it was.’

Although dug up in the 1960s it was never identified. The dinosaur lived during the Early Jurassic period of South Africa. Porro’s find was reported in the Journal of Vertebrate Paleontology.

 

Enlarge   dino

[Photo: The adult creatures were the size of turkeys but youngsters were half the size and only weighed half a pound, say researchers]

The first dinosaurs appeared about 230 million years ago, and the earliest known ones were meat eaters.

 There were other plant-eating dinosaurs at the time of Heterodontosaurus including the long-necked sauropods. But this little creature was one of the earliest of the ornithischians that soon become very important in the Age of Dinosaurs.

 Later ornithischians included the duck-billed dinosaurs, horned dinosaurs such as Triceratops and tank-like dinosaurs such as Ankylosaurus.

 While adult Heterodontosaurus were turkey-sized creatures that reached just over three feet in length and weighed about five pounds (2.5 kg), the juvenile likely weighed less than half a pound and would have been just about a foot and a half long.

Enlarge   skull

[Photo: The rare juvenile skull of a 190 million-year-old dinosaur may help explain when an important group of plant eaters branched off from their carnivorous cousins]

 The find also offers a rare chance to compare a young dinosaur to adults in the species. Porro said the eyes in the juvenile skull are much bigger, and the nose is much shorter.

 ‘It’s the same things that makes puppies and kittens appealing,” she said. “I think it’s adorable.’

source: http://www.dailymail.co.uk/sciencetech/article-1080194/One-worlds-smallest-dinosaurs-discovered-ate-meat-AND-plants.html

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Other links:

Tiny Juvenile Dinosaur Fossil Sheds Light On Evolution Of Plant Eaters
Science Daily (press release) – 6 ore fa
ScienceDaily (Oct. 23, 2008) — One of the smallest dinosaur skulls ever discovered has been identified and described by a team of scientists from London,
Tiny dinosaur on verge of swearing off meat
Reuters UK – 10 ore fa
By Julie Steenhuysen CHICAGO (Reuters) – A rare juvenile skull of a 190 million-year-old dinosaur may help explain when an important group of plant eaters
Dinosaur ‘was turning vegetarian’
The Press Association – 10 ore fa
One of the smallest dinosaur skulls ever discovered belonged to a creature in the process of turning vegetarian, say scientists.
One of world’s smallest dinosaurs discovered that ate meat AND plants
Daily Mail – 1 ora fa
By Daily Mail Reporter Laura Porro with her amazing find. The skull of a Heterodontosaurus had lain in a drawer since the 1960s One of the world’s smallest
Tiny Skull Sheds Light on Strange Dinosaur Diets
LiveScience.com – 9 ore fa
By Jeanna Bryner, Senior Writer Juveniles of Heterodontosaurs (the little ones in the illustration) already sported fang-like canines, and so like the

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Original article:

Journal of Vertebrate Paleontology (the link will be inserted when available) (Bioone)

ottobre 24, 2008 Posted by | - Ornitopodi, - R. Dinosauri, Africa, Articolo sc. di riferimento, Bl - Top posts, Italiano (riassunto), Lang. - Italiano, P - Evoluzione, P - morfologia funzionale, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , , | Lascia un commento

2008-10-16 – Paleoantropologia: Migrazioni ominidi dall’Africa (Paleoanthropology, ominids, migrations)

Quale strada per uscire dall’Africa?

Le prime popolazioni di Homo sapiens avrebbero seguito il corso dei fiumi del bacino centrale verso il Mediterraneo

 L’ipotesi che la Valle del Nilo sia stata la più probabile via di migrazione verso il Mediterraneo per le popolazioni di Homo sapiens anatomicamente moderno, circa 120.000 anni fa, va rivista. Uno studio pubblicato su Proceedings of the National Academy of Science (Pnas) mostra, infatti, che le condizioni climatiche avrebbero creato un corridoio attraverso il deserto in un’area molto più a Nord.

Sebbene la regione sub-sahariana sia ormai considerata da tutti la culla del genere umano, le posizioni degli antropologi riguardo a quali rotte questi popoli abbiano seguito per colonizzare le altre regioni sono controverse. Secondo i ricercatori della Bristol University, che hanno svolto i loro studi in collaborazione con le università di Southampton, Oxford, Hull e Tripoli, le antiche popolazioni si sarebbero spostate attraversando il Sahara Centrale e non la Valle del Nilo.

Durante l’ultimo periodo interglaciale (130-170.000 anni fa) infatti, precipitazioni consistenti interessarono una zona più a Nord dell’Africa Sub-sahariana e determinarono la formazione di un “corridoio umido” attraverso la Libia. “Immagini radar hanno confermato l’esistenza di corsi d’acqua fossili che scorrevano attraverso la Libia verso il Mediterraneo, provenienti dal bacino idrico presente nel Sahara Centrale”, ha spiegato Anne Osborne, co-autrice della pubblicazione: “Le analisi geochimiche hanno poi dimostrato che questi canali risalgono all’ultimo periodo interglaciale. Il bacino idrico, costituito da una zona di rocce vulcaniche, è considerato il limite di questa area bagnata”. L’ipotesi è supportata sia dalle analisi isotopiche di conchiglie recuperate in questi corsi d’acqua fossili, sia dal ritrovamento di artefatti umani simili in Ciad, Sudan e Libia. (e.r.)

fonte: http://www.galileonet.it/news/10678/quale-strada-per-uscire-dallafrica

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Official article:

A humid corridor across the Sahara for the migration of early modern humans out of Africa 120,000 years ago

PNAS doi:10.1073/pnas.0804472105

  • Anne H. Osborne,
  • Derek Vance,
  • Eelco J. Rohling,
  • Nick Barton,
  • Mike Rogerson,
  • and Nuri Fello

Abstract:

It is widely accepted that modern humans originated in sub-Saharan Africa ≈150–200 thousand years ago (ka), but their route of dispersal across the currently hyperarid Sahara remains controversial. Given that the first modern humans north of the Sahara are found in the Levant ≈120–90 ka, northward dispersal likely occurred during a humid episode in the Sahara within Marine Isotope Stage (MIS) 5e (130–117 ka). The obvious dispersal route, the Nile, may be ruled out by notable differences between archaeological finds in the Nile Valley and the Levant at the critical time. Further west, space-born radar images reveal networks of—now buried—fossil river channels that extend across the desert to the Mediterranean coast, which represent alternative dispersal corridors. These corridors would explain scattered findings at desert oases of Middle Stone Age Aterian lithic industries with bifacial and tanged points that can be linked with industries further to the east and as far north as the Mediterranean coast. Here we present geochemical data that demonstrate that water in these fossil systems derived from the south during wet episodes in general, and penetrated all of the way to the Mediterranean during MIS 5e in particular. This proves the existence of an uninterrupted freshwater corridor across a currently hyperarid region of the Sahara at a key time for early modern human migrations to the north and out of Africa.

ottobre 16, 2008 Posted by | Africa, Articolo sc. di riferimento, Lang. - Italiano, P - Paleoantropologia, Paleontology / Paleontologia | , , , , , , | Lascia un commento

Nuove considerazioni su “Lucy”

Lucy, the 3.2 million-year-old fossil, is a key piece in evolution’s puzzle

By TOM PAULSON
P-I REPORTER

Some 3 million years or so after her descendants arrived in the Pacific Northwest, Lucy represents just how far we have come from those days of wandering the savannas of Africa, scavenging for food, avoiding predators and awaiting the rapid expansion of a brain that today allows us to, among other things, ponder our origins.

 

She wasn’t human. But she wasn’t really an ape, either. She was, for many, a hint of humankind to come.

“Lucy is simply phenomenal,” said Patricia Kramer, an anthropologist at the University of Washington. “You can see yourself in her.”

You can, perhaps, as long as you are among those who can imagine having evolved along with chimpanzees, gorillas and other primates from a common — and now extinct — ancestor many millions of years ago. Not everyone can so easily imagine this, of course, whether because of conflicting religious beliefs or just that vague “sense” we have of human beings as somehow different, special, compared with the rest of creation.

   
   
   

However the metaphysical debate of our place in the cosmos may some day get resolved, there’s little debate within the scientific community today as to the significance of Lucy’s role in human evolution on Earth.

“She occupies a pivotal place on the human family tree,” said Donald Johanson, the American paleoanthropologist who, with his colleagues, discovered the fossil in 1974 near the northern Ethiopian community of Hadar. “We now know that one of the first significant things our ancestors did was to stand up, to walk on two feet instead of four.”

Lucy is still one of the most complete fossils from an early group of hominids (pre-humans) to routinely walk on two feet. This may sound like no big deal to us 21st century bipeds. But scientists say this was a key evolutionary adaptation probably caused by climate change, which forced our ancestors to shift from forest skills to operating on the savannas. It appears to have triggered other critical changes in our physique and behavior that led to modern humans.

More on those changes later. First, why is the fossil named Lucy?

“After the discovery, we kept listening to The Beatles’ song ‘Lucy in the Sky with Diamonds’ in camp and a girlfriend of mine suggested we call her Lucy,” said Johanson, who neglected to mention the much-documented celebratory partying that also took place that night. “The name just stuck. I’m amazed at how this helped to make her into this popular icon for human evolution.”

But it wasn’t just The Beatles who lent Johanson’s discovery such prominence and recognition.

“Lucy forced us to rewrite much of the science,” said Gerry Eck, a retired UW anthropologist who worked with Johanson in Ethiopia on expeditions after Lucy was uncovered. “Evolutionary history is basically a puzzle with a lot of missing pieces. Lucy helped fill in a big piece of the puzzle.”

Technically, Lucy is a fossil member of a class of hominids, or proto-humans, known as Australopithecus afarensis who lived between 3.9 million and 2.9 million years ago.

Scientists use a lot of confusing Latin names for (and frequently argue about) labeling members of the human evolutionary family tree. For simplicity’s sake, human evolution can be broken into three phases — early and very apelike hominids, Australopiths such as Lucy and our genus Homo.

Lucy and her ilk occupied a critical phase in the evolutionary process that scientists believe led to a variety of other pre-modern human species such as Homo erectus, Homo neanderthalensis (the Neanderthals) and eventually to us, Homo sapiens.

Australopithecus is Latin for southern ape. Lucy’s species name A. afarensis means she is the southern ape who hails from Afar, the region in Ethiopia where she was discovered. She stood about 3.5 feet tall, but still had a very small brain. Back in the 1970s, scientists were still arguing over what came first in human evolution — growing a much bigger brain or moving from four-legged to two-legged walking.

Unlike most such ancient fossils, Lucy was more than just a piece of skull, femur or jaw. She was 40 percent intact, including much of her skull and most of her pelvis.

It was her pelvis and leg structure that nailed it: Bipedalism clearly had preceded the boom in brains.

“There was no question that we were bipedal millions of years before our brains got big,” said the UW’s Kramer.

“It was a spectacular find,” Eck agreed. This caused a bit of a fuss, he added, because Johanson was a relative newcomer to the field and, based on Lucy, was introducing a revolutionary new interpretation of how we evolved.

Put brutally simply, here is a quick summary of how Lucy’s bipedalism contributed to human evolution:

 

  • Standing up freed our hominid hands to eventually allow for tool use.  
  • Tool use led to greater success in hunting or otherwise acquiring meat in the diet.  
  • A diet rich in meat provided more of the basic biochemical building blocks needed for brain development.  
  • Someone, at some point, learned how to use fire. Someone started talking. Someone started writing.
  • It’s an absurd abbreviation of our story, of course, and of the scientific evidence. The complete story of human evolution, like the human brain, is too incredibly rich and complex to be so simplistically boiled down to such a short description. What makes Lucy so special is that, to some extent, she represents a stage in our prehistory, our evolutionary development, that we can comprehend.

    There are still many mysteries, many gaps and unresolved issues to this story. Why did the Neanderthals disappear some 28,000 years ago? Did they really disappear or did they interbreed with us? Do the diminutive fossils dubbed the “Hobbits” recently discovered on the Indonesian island of Flores represent a new branch of Homo that lived contemporaneously with modern humans?

    What does it really mean to be human?

    Lucy certainly can’t answer all the questions, but she did answer some of the most significant ones for human evolution. As such, she likely will forever be regarded as a crucial turning point in our ongoing search to understand who we are, how we got here and, perhaps, where we are headed.

    “Lucy really is the link, the common ancestor, between the older, more apelike creatures and the hominids that gave rise to us,” Johanson said.

    “The field of paleontology is still quite young and we are in for an enormous number of further surprises. But Lucy will always be a touchstone.”

    P-I reporter Tom Paulson can be reached at 206-448-8318 or tompaulson@seattlepi.com.
    ————————————————————————————-
    other links (news) :
    SA academic called on to solve fossil mystery
    Independent Online – 4 ore fa
    By Shaun Smillie They died suddenly in an Ethiopian riverbed – killed by a single catastrophic event that claimed babies, and possibly their mothers and
     
    ‘Lucy’s Legacy’ holds treasures for all ages at the Pacific
    Seattle Post Intelligencer – 15 ore fa
    By DOREE ARMSTRONG For such a little girl, she sure has had an enormous impact on the world. The 1974 discovery of 3 1/2-foot-tall Lucy, the oldest and most
    Lucy on display with controversy
    Seattle Times – 2 ott 2008
    Lucy, the world’s most famous fossil, goes on exhibit in Seattle this week. But some scientists say the fragile bones should never have left Ethiopia.
    Ethiopia’s rich heritage: Lucy’s birthplace is globally significant
    Ethiopian Review – 19 ore fa
    By TOM PAULSON SEATTLE, WASHINGTON – It is fitting that one of the most signature discoveries of humankind — a finding that has helped define a big part of

    settembre 30, 2008 Posted by | - Primati, Africa, P - Paleoantropologia, Paleontology / Paleontologia, x Terziario | , , , , , , , , | Lascia un commento

    2008-09-01 – Disputa sul Sahelanthropus tchadensis

    Finder of key hominid fossil disputes 7-million-year dating

    PARIS (AFP) — A fresh storm has broken out over an ancient fossil presented by its defenders as a forebear of humanity and dismissed by its critics as the remains of a vulgar chimp.

    Controversy has swirled around Toumai, the name given to the nearly-complete skull, ever since it was found in the Chadian desert in 2001.

    Toumai’s big defender is French palaeontologist Michel Brunet, a professor at the prestigious College de France, who says Toumai walked the Earth shortly after chimpanzees and hominids diverged from a common ancestral primate.

    Brunet has been roundly attacked in other quarters.

    Critics are incensed that he has given a hominid honorific (Sahelanthropus tchadensis) to a creature whose cranium, in their view, was too squashed to be that of a pre-cursor of Homo sapiens.

    They calculate that Toumai’s height was no more than 120 centimetres (four feet) — or that of an adult chimpanzee.

    Brunet appeared to have scored a knockout blow in February this year, when radiological measurements estimated that the soil where Toumai was found was between 6.8 million and 7.2 million years old.

    The study appeared in a top-line US journal, the Proceedings of the National Academy of Sciences.

    But the man who discovered Toumai, Alain Beauvilain, of the University of Paris at Nanterre, has now publicly challenged this estimate.

    Beauvilain declined to take part in the hominid-vs.-chimp debate, but said he questioned the dating’s methods and the way it had been presented to the public.

    “It’s time to set the record straight,” he told AFP.

    In general, radiodating of the sediment in which a fossil is found is considered to be a good guide to when the creature died, its remains eventually becoming covered by soil or other debris.

    But Beauvilain, a Chadian fossil expert of long standing, says that, contrary to Brunet’s assertions that the fossil had been “unearthed,” the cranium was found loose on the sand.

    A thick blue ferruginous, or iron-based, mineral encrusted the skull, which showed clear signs of weathering from desert conditions, Beauvilain says in a commentary in the South African Journal of Science.

    Beauvilain says it is clear that the soil around the find, and possibly the find itself, had been shifted by wind or erosion, a phenomenon that can happen swiftly and frequently in the desert.

    So carbon-dating the soil and attributing that to the skull was a perilous exercise, he says.

    “How many times was it exposed and reburied by shifting sands before being picked up?” he asks in the commentary.

    Beauvilain also takes issue with the soil samples used for the PNAS study and analysed by experts from France’s National Centre for Scientific Research (CNRS).

    He says these samples were taken selectively and did not give a full picture of the depth and range of topography in which the find was made. He describes some of the collection choices as “astonishing.”

    On the same grounds, Beauvilain attacks Brunet’s dating of an ancient Chadian jawbone, dubbed Abel and estimated to be between three million and 3.5 million years old.

    “Abel,” too was picked up on the surface in 1995, and was not embedded in the soil, he says, showing photos of both finds on their day of discovery.

    The debate is important because of its implications for anthropology.

    Toumai — the name means “hope of life” in the local Goran language — was found 2,500 kilometers (1,500 miles) west of the Great Rift Valley, until now considered the cradle of humanity.

    So if the skull’s dating is right, it implies the early hominids ranged far wider from East Africa, and far earlier, than previously thought.

    The discovery also implies hominids evolved quickly from apes after they split from a common primate ancestry.

    Hominids are considered the forerunners of anatomically modern humans, who appeared on the scene about 200,000 years ago.

    Still unclear, though, is the exact line of genealogy from these small, rather ape-like creatures to the rise of the powerfully-brained Homo sapiens.

    http://afp.google.com/article/ALeqM5hmOMNXMKmvSlX6RhmnJ69SJLo85A

    settembre 20, 2008 Posted by | Africa, P - Paleoantropologia, Paleontology / Paleontologia, x Terziario | , , , , , , | 1 commento

    Un cimitero nel Sahara

    Un cimitero nel Sahara

     

    Scritto da Marta Meloni – italoeuropeo, 22-08-2008 22:46

    Un cimitero nel Sahara.Il Sahara non è sempre stato il deserto che conosciamo. Due diverse popolazioni umane hanno abitato per più di duemila anni la regione sahariana dell’età della pietra, allora ricca di vegetazione.

    Durante una spedizione per lo studio dei dinosauri, un gruppo di ricercatori, guidati da Paul Sereno dell’Università di Chicago, ha casualmente scoperto il più grande cimitero dell’età della pietra nel sito archeologico di Gobero nel Niger.

    Gli studiosi hanno finora esaminato 67 delle circa 200 tombe che compongono il cimitero di Gobero scoprendo molti dettagli sui Kiffian e i Teneriani, le due popolazioni che si sono avvicendate nell’occupazione della regione del Tenerè.

    I Kiffian hanno abitato il Tenerè sicuramente nel periodo compreso tra il 7700 a.C. e il 6200 a.C. Insieme agli scheletri di persone di alta statura sono state ritrovate delle punte di arpioni e delle ossa di grandi animali della savana. Ciò fa pensare a una popolazione di raccoglitori-cacciatori che abitava una zona nei pressi di un lago.

    Nel 6200 a.C. la regione sahariana conobbe un primo periodo di estrema siccità, che durò circa mille anni, in cui i Kiffian sembrano essere improvvisamente scomparsi.

    Con la ricomparsa delle piogge un’altra popolazione, quella dei Teneriani, si stabilì nella regione del Tenerè. I Teneriani erano di corporatura decisamente più piccola e gracile dei Kiffian e si servivano quindi di attrezzi per la caccia e la pesca che necessitavano di una minor forza fisica rispetto a quelli utilizzati dai Kiffian.

    Oltre alla pesca e alla caccia di animali selvatici, i Teneriani si dedicavano all’allevamento del bestiame. Avevano inoltre delle credenze spirituali e praticavano il culto dei morti. È stata infatti portata alla luce una tomba, risalente a 5300 anni fa, con i resti di una donna e due bambini la cui posizione indica un abbraccio reciproco, adagiati su un letto di fiori.

    Lo studio delle tombe rimanenti può farci conoscere molti altri dettagli della vita di queste popolazioni. Elena Garcea dell’Università di Cassino, che collabora allo studio, afferma che “possiamo imparare molto da questi resti sull’adattamento degli umani ai cambiamenti climatici. In questa zona l’ambiente è cambiato diverse volte in un periodo di tempo relativamente breve e possiamo usare questi reperti per capire come le popolazioni hanno affrontato questi cambiamenti.”

    Lo studio è pubblicato sulla rivista PloS ONE (Paul Sereno et al, Lakeside Cemeteries in the Sahara: 5000 Years of Holocene Population and Environmental Change, PLoS ONE 3(8): e2995. doi:10.1371/journal.pone.0002995, 14 agosto 2008)

    http://www.italoeuropeo.it/index.php?option=com_content&task=view&id=1182&Itemid=1

    settembre 19, 2008 Posted by | 1 Olocene, Africa, FREE ACCESS, P - Paleoantropologia, P - Ritrovamenti fossili | , , | Lascia un commento