Paleonews

Il blog dedicato ai Paleontologi !!!!

2009-03-05 – Teropodi con postura da uccelli (Dinosaur imprints, birdlike arm anatomy)

Tracce di un Teropode a riposo (Giurassico inferiore, Utah – USA) rivelano una postura da uccello

Vedi approfondimento sul Blog Theropoda:

Un nuovo sito icnologico dimostra che i theropodi si accucciavano come… (Milner et al., 2009)

—————————————————————————————

Sitting dinosaur leaves karate chop handprints – March 04, 2009

45376624.jpgAncient meat-eating dinosaurs held their arms with palms facing inwards like their bird descendants, a rare set of 198-million-year-old fossilised handprints has revealed. An analysis of the prints, published this week in PLoS One, supports theories that even very early therapods [lit. ‘beast feet’] such as tyrannosaurs and velociraptors had bird-like forelimbs, and walked only on two legs, well before they evolved feathery wings.

The handprints came from a dinosaur that sat down on the edge of a lake in St George, Utah, and extended its arms far enough to leave sediment marks. Six other resting dinosaur traces have been reported before, but they all lack clear hand prints.

This means, reports the Chicago Tribune, that we must banish images of tyrannosaurs holding their forearms like monkeys, with palms facing downwards – a posture that palaeontologists apparently term the “bunny position” – as depicted in Jurassic Park. Instead, we must imagine that dinosaurs were extremely good at holding basketballs.

“What this seems to imply is that, even from fairly early in their history, dinosaurs were entirely bipedal and weren’t using their forearms to support themselves in any way,” paleontologist Tom Holtz of the University of Maryland, says. “Because of that, the hands could specialize as weapons, to grab on to a struggling animal or to fight with other dinosaurs.”

Image: Dilophosaurus wetherilli in bird-like resting pose/Heather Kyoht Luterman

source: Nature.com

—————————————————————————–

What a dinosaur handprint reveals

Los Angeles Times – ‎3-mar-2009‎
At left, dinosaur tracks with hand prints show bird-like inward-facing palms at Johnson Farm, Utah. At right, an artist’s reconstruction shows the formation
National Geographic —————————————————————————–

 

 free access article on PlosOne

Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace

Andrew R. C. Milner, Jerald D. Harris, Martin G. Lockley, James I. Kirkland, Neffra A. Matthews

Abstract PDF

 

 

Annunci

marzo 5, 2009 Posted by | - R. Dinosauri, - Teropodi, - Uccelli / Birds, 2 Jurassic / Giurassico, America Northern, An. Vertebrates, Articolo sc. di riferimento, Bl - Top posts, FREE ACCESS, Mesozoic, P - Evoluzione, P - Impronte, P - morfologia funzionale, P - Paleoetologia, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , | Lascia un commento

2009-03-01 – Perù: fossile di uccello gigante (Giant fossil bird)

Perù: paleontologia, trovato fossile uccello di 10mln di anni

Sabato 28 febbraio 2009 02.25
Il fossile di un gigantesco uccello vissuto circa 10 milioni di anni fa è stato ritrovato nella regione di Ocucaje, nel Perù meridionale. Mario Urbina, paleontologo nel Museo nazionale di storia naturale, ha detto che il volatile sembra appartenere ai pelagornitidi, una specie comparsa circa 50 milioni di anni fa e estinta 2,5 milioni di anni fa a causa dei cambiamenti climatici. Questo tipo di uccello aveva un’apertura alare di oltre sei metri, nidificava in prossimità delle coste e si cibava dei pesci che riusciva a catturare tuffandosi nel Pacifico. Nel corso di scavi in corso nella regione, alcuni ricercatori hanno ritrovato la testa fossile dell’uccello, lunga circa 40 centimetri. Oltre alla considerevole apertura alare, una delle caratteristiche più curiose di questa specie è la presenza di denti all’estremità del becco.
———————————————————-

Fossil skull of giant toothy seabird found in Peru

LIMA, Peru (AP) — The unusually intact fossilized skull of a giant, bony-toothed seabird that lived up to 10 million years ago was found on Peru’s arid southern coast, researchers said Friday.

The fossil is the best-preserved cranium ever found of a pelagornithid, a family of large seabirds believed to have gone extinct some 3 million years ago, said Rodolfo Salas, head of vertebrate paleontology at Peru’s National History Museum.

The museum said in a statement that the birds had wingspans of up to 20 feet (6 meters) and may have used the toothlike projections on their beaks to prey on slippery fish and squid. But studying members of the Pelagornithidae family has been difficult because their extremely thin bones — while helpful for keeping the avian giants aloft — tended not to survive as fossils.

“Its fossils are very strange, very rare and very hard to find,” Salas told The Associated Press.

The cranium discovered in Peru is 16 inches (40 centimeters) long and is believed to be 8 million to 10 million years old, based on the age of the rock bed in which it was found.

“Rarely are any bones of these gigantic, marine birds found fossilized uncrushed, and to find an uncrushed skull of this size is very significant,” said Ken Campbell, curator of vertebrate zoology at the Natural History Museum of Los Angeles.

Campbell, who examined photos of the find but was not involved in the dig, said he knows of “no specimen of comparable quality.”

Dan Kepska, a paleontology researcher at North Carolina State University who also was not part of the project, agreed that the skull is the most complete ever reported.

He called the birds “one of the great enigmas of avian paleontology.”

With fossils discovered in North America, North Africa and even Antarctica, Kepska said, the birds were ubiquitous only a few million years before humans evolved and scientists puzzle over why they died out. Some believe they are related to gannets and pelicans, while other say they are related to ducks.

Campbell said the Peru find “will undoubtedly be of great importance to our understanding of these gigantic birds, and it will help clarify the relationships of the other fossil pelagornithids found in the Pisco Formation.”

The formation, a coastal rock bed south of the capital, Lima, is known for yielding fossils of whales, dolphins, turtles and other marine life dating as far back as 14 million years.

source: AssociatedPress

———————————————————-

Fossil skull of giant toothy seabird found in Peru

The Associated Press – ‎28-feb-2009‎
The fossil is the best-preserved cranium ever found of a pelagornithid, a family of large seabirds believed to have gone extinct some 3 million years ago,
CBC.ca

 

 

marzo 1, 2009 Posted by | - Uccelli / Birds, America Southern, An. Vertebrates, Cenozoic, Lang. - Italiano, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , | 2 commenti

2009-01-19 – Anchiornis: un nuovo dinosauro piumato (primitive feathered dinosaur)

Un nuovo dinosauro piumato scoperto in Cina, l’Anchiornis, può aiutare a comprendere meglio la “transizione” da dinosauri ad ucccelli essendo “più basale di Archaeopteryx.

——————————————————————————————–

New Feathered Dinosaur Adds to Bird Evolution Theory

Kevin Holden Platt in Beijing
for National Geographic News
January 16, 2009

A fossil of a primitive feathered dinosaur uncovered in China is helping scientists create a better model of how dinosaurs evolved into modern birds.

The winged dinosaur is still in the process of being dated, and might have lived toward the end of the Jurassic period, which lasted from 208 to 144 million years ago.

Anchiornis - A fossil of a primitive feathered dinosaur uncovered in China (above) is helping create a better model of how dinosaurs evolved into modern birds, experts said in January 2009.

Anchiornis - A fossil of a primitive feathered dinosaur uncovered in China (above) is helping create a better model of how dinosaurs evolved into modern birds, experts said in January 2009. - Photograph courtesy Xu Xing

In many ways, it is “more basal, or primitive, than Archaeopteryx,” said paleontologist Xu Xing at Beijing’s Institute of Vertebrate Paleontology and Paleoanthropology. Archaeopteryx, the earliest known bird, lived 150 million years ago.

The protobird is “very close to the point of divergence” at which a new branch of winged dinosaurs first took flight, said Xu.

The new species, called Anchiornis huxleyi, was discovered in the ashes of volcanoes that were active during the Jurassic and Cretaceous (144 to 65 million years ago) periods in what is now northeastern China.

(Read about the prehistoric world.)

Anchiornis, which is Greek for “close to bird,” measured just 13 inches (34 centimeters) from head to tail and weighed about 4 ounces (110 grams).

The dinosaur’s body and forelimbs were covered with feathers, and it “might have had some aerial capability,” Xu said.

Anchiornis is one of the smallest theropod dinosaurs ever uncovered,” Xu explained. Theropods were a group of carnivorous dinosaurs that walked on two legs.

Taking Wing

The fossil provides new clues about how feathers, wings, and flight progressively appeared among theropods, along with evidence that certain types of feathered dinosaurs decreased in stature even as their forelimbs became elongated.

The compact structure of Anchiornis “reinforces the deduction that small size evolved early in the history of birds,” Xu explained”[Anchiornis] exhibits some wrist features indicative of high mobility, presaging the wing-folding mechanisms seen in more derived birds,” he said.

“The wrist is a big part of the formation of wings, and pivotal to flight,” Xu added. “During flight, steering and flapping greatly depend on the wrist.”

Despite this protobird’s relatively advanced feathers and wrist, it is unclear if Anchiornis could actually engage in powered flight.

“Behavior and biomechanics are very difficult to determine solely from the fossil record, and perhaps flight is impossible to determine,” said Mark Norell, chairman and curator of the division of paleontology at the American Museum of Natural History in New York.

“Feathers have lots of functions, and probably evolved as thermoregulators,” said Norell, who closely examined the fossil during a trip to Beijing.

“Dinosaurs might have used feathers for sexual display or to make themselves appear bigger, or as camouflage to avoid predators,” he said.

Patterns of spots and bars evident on one species of feathered dinosaur from China might have functioned as a camouflage defense, Norell added.

(Related: “First Dinosaur Feathers for Show, Not Flight?” [October 22, 2008].)

Prehistoric Paradise

Xu said that the region in northeastern China where most of the world’s feathered dinosaurs, including Anchiornis, have been discovered is a virtual paradise for dinosaur hunting.

“This area has three circles of volcanic activity,” with eruptions that intermittently covered and preserved entire biospheres starting from the early Jurassic.

“Volcanos periodically killed the animals and plants and preserved them perfectly in volcanic ash,” he said.

“Sometimes the volcanic ash even preserves soft tissues, leaving behind an exceptional 3-D fossil.”

source: http://news.nationalgeographic.com/news/2009/01/090116-feathered-dinosaur_2.html

gennaio 19, 2009 Posted by | - R. Dinosauri, - Teropodi, - Uccelli / Birds, 2 Jurassic / Giurassico, Asia, Italiano (riassunto), Mesozoic, P - Evoluzione, P - morfologia funzionale, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , | Lascia un commento

2008-12 – TAC for Archaeopteryx

Stanford scientists scan birdlike dinosaur for evolution clues

dicembre 31, 2008 Posted by | - R. Dinosauri, - Uccelli / Birds, 1, Bl - Top posts, P - Evoluzione, P - morfologia funzionale, Paleontology / Paleontologia | , , , , , , , , , | Lascia un commento

2008-12-23 – I dinosauri e le cure parentali (Dinosaurs and parental care)

 

DINOSAURI I PRIMI BABYSITTER

2008-12-19 19:06
 
Fare il babysitter è un lavoro antichissimo, preistorico addirittura, come mostrano le uova di dinosauro che 75 milioni di anni fa erano covate da maschi. Secondo uno studio americano pubblicato questa settimana su Science, i maschi dei terribili velociraptor, i dinosauri carnivori onnipresenti nel romanzo e nel film “Jurassic Park”, erano degli ottimi babysitter.

Come accade oggi in moltissime specie di uccelli, erano i maschi ad occuparsi del nido, a sorvegliare, difendere e accudire le uova. “Si ritiene comunemente che le femmine si concentrassero nel deporre le uova e nel procacciare il cibo e stanno diventando sempre più numerose le evidenze che additano i maschi come coloro che effettivamente si prendevano cura delle uova”, osserva il coordinatore della ricerca, Jason Moore, dell’università del Texas. In collaborazione con le università del Montana e della Florida e con il Museo Americano di Storia Naturale di New York, Moore ha scoperto e studiato sei nidi di dinosauro nello Stato americano del Montana e in Mongolia. I nidi risalgono a a circa 75 milioni di anni fa, sono in buono stato di conservazione e ognuno di essi contiene da 22 a 30 uova.

Sui nidi e attorno ad essi si trovano numerosa ossa i individui adulti. I ricercatori hanno scoperto che uova e ossa appartengono almeno a tre specie di dinosauri: troodonti, oviraptor e citipati, parenti dei velociraptor resi celebri da “Jurassic Park”. Nelle tre le specie, tutte fortemente imparentate con i moderni uccelli, le ossa trovate in prossimità dei nidi appartenevano a maschi. Sono infatti prive delle cavità che si formavano all’interno delle ossa delle femmine quando deponevano le uova. “Le ossa che abbiamo trovato più vicine alle uova – rileva Moore – non mostrano alcuna caratteristiche che indichi l’appartenenza a femmine di dinosauro”.

Di qui la conclusione dei ricercatori che in alcune specie di dinosauri erano i maschi a prendersi cura delle uova e a sorvegliarle, proprio come oggi accade negli uccelli, nei quali i maschi partecipano alle cure parentali per il 90% del tempo. Nei mammiferi, invece, i maschi si prendono cura della prole solo nel 5% delle specie. Per i ricercatori la scoperta dei dinosauri-babysitter è un punto di partenza per studiare comportamenti analoghi in altre specie animali.

 
 

ANSA

DINOSAURI I PRIMI BABYSITTER
ANSA – 2 ore fa
Secondo uno studio americano pubblicato questa settimana su Science, i maschi dei terribili velociraptor, i dinosauri carnivori onnipresenti nel romanzo e nel film “Jurassic Park”, erano degli ottimi babysitter. Come accade oggi in moltissime specie di
dinosauri i primi babysitter L’Unione Sarda
e altri 6 articoli simili »

—————————————————————————————————————————-

 

 

Florida State researcher Erickson ties rare bird behavior to dinosaur ancestors

Sure, they’re polygamous, but male emus and several other ground-dwelling birds also are devoted dads, serving as the sole incubators and caregivers to oversized broods from multiple mothers. It is rare behavior, but research described in the Dec. 19 Science found that it runs in this avian family, all the way back to its dinosaur ancestors. 

Gregory Erickson

Gregory Erickson

 Scientists had long wondered about the origins of polygamy and paternal care patterns among modern-day Paleognathes — an ancient avian lineage that branched off soon after birds evolved from dinosaurs and includes ostriches, emus and tinamous. No such reproductive behavior exists among the vast majority of other vertebrates. Males contribute to parental care in less than 5 percent of mammal and non-avian reptile species, and while more than 90 percent of bird species co-parent to some degree, it is only among the Paleognathes that both polygamy and paternal care rule.

Now, in a groundbreaking paper (“Avian Paternal Care Had Dinosaur Origin”), paleobiologist Gregory M. Erickson of The Florida State University and researchers from three other institutions connect the evolutionary dots linking the polygamous, paternal reproductive patterns of extant (living) birds to the behavior of their extinct dinosaur kin.

“In those cases where adult dinosaurs have been found on top of nests, we found that the volume or mass of the egg clutch (total number of eggs in the nest) is very large relative to the size of the nesting animals,” Erickson said. “This suggests multiple females contributed the eggs and the male guarded them. Notably, the ratio of egg volumes to the nesting animal’s size is consistent with those in living birds where the male is the sole or primary nest attendant.”

The researchers now had their link from the theropod dinosaurs (omnivores and carnivores that walked on two hind legs with bird-like feet) to the polygamy and nesting scenarios exhibited by their avian descendants, according to David Varricchio of Montana State, the study’s principal investigator.

But to test the theory, Varricchio needed to determine the sex of the brooding dinosaurs whose bones have been found atop those communal nests.

For that, he turned to Erickson at Florida State, a renowned expert in dinosaur paleobiology.

Erickson examined the bone microstructure of tibiae (shin bones), femora (thigh bones) and metatarsus (ankle bones) from oviraptorids and deinonychosaurs (Jurrasic Park “raptors”) — small theropod dinosaurs whose adult skeletons have been repeatedly discovered in brooding postures atop nests containing dozens of large eggs.

The key was what he didn’t find in the bones: They showed no signs whatsoever of the maternal and reproductively associated microscopic features common to living non-Paleognath bird groups, extinct non-avian dinosaurs or living reptiles.

“I found no evidence of medullary bone (the extra bone laid down by breeding female birds and dinosaurs to make eggs) or extensive bone resorbtion (the means by which female reptiles such as crocodiles acquire mineral salts to make eggs),” Erickson said. “This is consistent with the brooding dinosaurs being males.”

Thus, the researchers had confirmation that the dinosaurs found in nests with large egg clutches were polygamistic males and the source of the peculiar avian behavior. Moreover, those brooding dinosaurs were fathers — and today’s emus, rheas and tinamous owe their paternal care model to them.

Co-authors of “Avian Paternal Care Had Dinosaur Origin” — accessible via the journal Science Web site at www.sciencemag.org/current.dtl — are Florida State’s Erickson, associate professor of anatomy and vertebrate paleobiology in the Department of Biological Science; Varricchio, Frankie D. Johnson and John J. Borkowski of Montana State University; Jason R. Moore of Texas A&M University; and Mark A. Norell of New York City’s American Museum of Natural History.

By Libby Fairhurst

source: http://www.fsu.edu/news/2008/12/18/rare.bird/


Canada.com

Dinosaur day care dads
Science News – 3 ore fa
New analyses of fossilized dinosaur eggs and bones suggest that male dinosaurs likely sat on nests and cared for their young, similar to the parental division of labor seen in some modern birds.
Daddy day-care: dinosaur fathers guarded the eggs Reuters
Dinosaur Dads Played “Mr. Mom”? National Geographic
eFluxMedia – Discover Magazine – FOXNews – eFluxMedia
e altri 56 articoli simili »


Scientist Live

Polygamy, Paternal Care In Birds Linked To Dinosaur Ancestors
Science Daily (press release) – 18 dic 2008
19 Science found that it runs in this avian family, all the way back to its dinosaur ancestors. Scientists had long wondered about the origins of polygamy and paternal care patterns among modern-day Paleognathes — an ancient avian lineage that
Odd bird fathering styles may come from dinos World Science
Avian Paternal Care Had Dinosaur Origin Science Magazine (subscription)
ScienceBlogs – United Press International
e altri 19 articoli simili »

—————————————————————————————————————————

Scientific article:

Avian Paternal Care Had Dinosaur Origin

David J. Varricchio, Jason R. Moore, Gregory M. Erickson, Mark A. Norell, Frankie D. Jackson, and John J. Borkowski
Science 19 December 2008: 1826-1828.
The large egg clutches of troodontid and oviraptor dinosaurs and evidence that fossils of brooding dinosaurs were males shows that paternal care was ancestral to birds.
Abstract »   Full Text »   PDF »   Supporting Online Material »  

dicembre 23, 2008 Posted by | - R. Dinosauri, - Teropodi, - Uccelli / Birds, 1, Articolo sc. di riferimento, Lang. - Italiano, P - Paleoetologia, Paleontology / Paleontologia, X - Science | , , , , , | Lascia un commento

2008-09-27 Trovato fossile di “Super-Papera” – Dasornis (GBR)

Fossil of 15ft duck in clay

DISCOVERY

The skull of a giant duck which had sharp teeth, a 15ft wingspan has been found in southern England.

The fossil of the Dasornis, which cruised seas covering the South East 50 million years ago, was buried in clay at the Isle of Sheppey, Kent.

Their wingspan – the length of a family car – meant they could cover huge distances. Latest research suggests the closest living relative of the bird is the humble duck.

Expert Gerald Mayr told journal Palaeontology the skull is “one of the best found”. It is now on show in Germany.

http://www.mirror.co.uk/news/top-stories/2008/09/27/fossil-of-15ft-duck-in-clay-115875-20755334/

 ————————————————————————————-

IT IS A PLANE? NO, IT’S A 16FT GOOSE…

IT WAS the Mother Goose of all time – a bird with a 16ft wing span which soared over southern England 50million years ago.

The bird had a 16 foot wing span and soared over the wetlands of prehistoric southern England

The bird had a 16 foot wing span and soared over the wetlands of prehistoric southern England Scientists discovered this Dasornis fossil skull buried in clay on the Isle of Sheppey Now a well-preserved fossil skull of the giant bird, a dasornis, has been found on the Isle of Sheppey off the north Kent coast, scientists announced yesterday.Dasornis was in many ways similar to the modern albatross, but its closest cousins are ducks and geese. Scientists discovered this Dasornis fossil skull buried in clay on the Isle of Sheppey

Dr Gerald Mayr, who described the discovery in the journal Palaeontology, said: “Imagine a bird like an ocean-going goose, almost the size of a small plane.

“These were pretty bizarre animals, but perhaps the strangest thing about them is that they had sharp, tooth-like projections along the cutting edges of the beak.

“No living birds have true teeth because their distant ancestors did away with them more than 100million years ago, probably to save weight and make flying easier.

“But the bony-toothed birds, like dasornis, are unique among birds in that they re-invented tooth-like structures.”

He added: “These birds probably skimmed across the surface of the sea, snapping up fish and squid.

“With only an ordinary beak, these would have been difficult to keep hold of, and the pseudo-teeth evolved to prevent meals slipping away.”

http://www.express.co.uk/posts/view/63421/It-is-a-plane-No-it-s-a-16ft-goose

 ————————————————————————————-
 ————————————————————————————-
A SKULL OF THE GIANT BONY-TOOTHED BIRD DASORNIS (AVES: PELAGORNITHIDAE) FROM THE LOWER EOCENE OF THE ISLE OF SHEPPEY
Plane-sized bird
Sydney Morning Herald – 1 ora fa
A STUDY has revealed a bird that swooped over waters covering what is now south-east England had wings that spanned five metres tip to tip and bony teeth to
Bird the size of plane found near London
ABC Online – 17 ore fa
Scientists have revealed the existence of a huge bird with bony teeth and wings spanning five metres, that once swooped over the wetlands of southern
When giant prehistoric geese roamed the earth
MSNBC – 18 ore fa
By Andrea Thompson Scientists have found a new huge and well-preserved fossil of a goose and duck relative that swam around what is now England 50 million
Lord of the skies was a giant goose with a beak full of crocodile
Times Online – 19 ore fa
A giant geese-like bird that was the size of a light aircraft and had a beak like a crocodile’s jaws has been found to have soared above Britain 50 million
Mother Of A Goose! Giant Ocean-going Geese With Bony-teeth Once
Science Daily (press release) – 20 ore fa
ScienceDaily (Sep. 26, 2008) — A 50 million year old skull reveals that huge birds with a 5 metre wingspan once skimmed across the waters that covered what
Mega-bird had a five-metre wingspan… and teeth
AFP – 21 ore fa
PARIS (AFP) — A bird that swooped over the waters covering what is now southeast England had wings that spanned five metres (16.25 feet) tip to tip and had
Giant prehistoric geese the size of small plane
Telegraph.co.uk – 21 ore fa
By Richard Alleyne Giant prehistoric geese the size of small aircraft once flew over Britain, scientists have discovered. Dasornis, which had a 16 ft
Fossil of 15ft duck in clay
Mirror.co.uk – 11 ore fa
The skull of a giant duck which had sharp teeth, a 15ft wingspan has been found in southern England. The fossil of the Dasornis, which cruised seas covering
Don’t ruck with this duck
The Sun – 15 ore fa
GIANT ducks sporting teeth and a 15ft wingspan once flew over Britain, experts said yesterday. One of the best-ever fossilised skulls of the creatures
One more terror for ancient ocean fish: monster ducks
World Science – 18 ore fa
As if the little fish of the ancient seas didn’t have enough terrifying predators to deal with, they also had to contend with duck-like birds,
Big bird: Experts unveil skull of giant duck with teeth and the
Daily Mail – 21 ore fa
By Daily Mail Reporter Instead of the fluffy little creatures seen today, these big birds boasted ‘teeth’, a 16ft wingspan and once flew over Britain.

 

GERALD MAYR
Forschungsinstitut Senckenberg, Sektion Ornithologie, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany; e-mail: Gerald.Mayr@senckenberg.de
Copyright © The Palaeontological Association, 2008
KEYWORDS
Fossil birds • bony-toothed birds • Dasornis emuinus • taxonomy • evolution • Eocene

ABSTRACT

Abstract: The first substantial skull of a very large Paleogene bony-toothed bird (Pelagornithidae) is described from the Lower Eocene London Clay of the Isle of Sheppey in England. The specimen is assigned to Dasornis emuinus (Bowerbank), based on a taxonomic revision of the large London Clay Pelagornithidae. Very large bony-toothed birds from the London Clay were known previously from fragmentary remains of non-comparable skeletal elements only, and Dasornis londinensis Owen, Argillornis emuinus (Bowerbank), A. longipennis Owen, and Neptuniavis miranda Harrison and Walker are considered junior synonyms of D. emuinus. The new specimen allows a definitive assignment of Dasornis to the Pelagornithidae and documents that this taxon closely resembles other bony-toothed birds in cranial morphology. It is hypothesized that giant size (i.e. a wingspan above 4 m) evolved only once within Pelagornithidae and that Dasornis emuinus is the sister taxon of the giant Neogene bony-toothed birds, which share a derived wing morphology.

Abstract References  |  Full Text: HTML, PDF (528k) | Related Articles | Citation Tracking

 

settembre 27, 2008 Posted by | - Uccelli / Birds, 6 Eocene, Articolo sc. di riferimento, Europa, FREE ACCESS, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , , , , , | Lascia un commento

Ritrovati i più antichi Pappagalli fossili

55 million year old fossil remains of parrots discovered near the North Sea
Scientific researchers have discovered the fossil remains of parrots in Scandinavia which are more than 55 million years old. The findings, published in the current issue of Palaeontology, indicate that parrots, which today only live in the tropics and the southern hemisphere, once flew wild over what is now Norway and Denmark. This suggests that parrots may have first evolved in the North, much earlier than had previously been considered.

“Obviously, we are dealing with a bird that is bereft of life, but the tricky bit is establishing that it was a parrot,” explains Dr David Waterhouse, the lead author of the scientific paper. “As with many fragile bird fossils, it is a wonder that anything remains at all, and all that remains of this early Danish parrot is a single upper wing bone (humerus). But, this small bone contains characteristic features that show that it is clearly from a member of the parrot family, about the size of a Yellow-crested Cockatoo.”

Dr Waterhouse, who is currently assistant curator of natural history at Norfolk Museums Service in Britain, was a PhD candidate at University College Dublin when the request to identify the mysterious bone was received from the Moler Museum on the Isle of Mors. He had received a scholarship from University College Dublin (UCD) and funding from the Irish Research Council for Science, Engineering and Technology (IRCSET).

“It isn’t as unbelievable as you might at first think that a parrot was found so far north.  When Mopsitta was alive, most of Northern Europe was experiencing a warm period, with a large shallow tropical lagoon covering much of Germany, South East England and Denmark,” says Dr Waterhouse. “We have to remember that this was only 10 million years after the dinosaurs were wiped out, and some strange things were happening with animal life all over the planet.”

“No Southern Hemisphere fossil parrot has been found older than about 15 million years old, so this new evidence suggests that parrots evolved right here in the Northern Hemisphere before diversifying further South in the tropics later on.”

Dr Waterhouse worked with Dr Gareth Dyke from the UCD School of Biology And Environmental Science, University College Dublin, Bent Lindow from the University of Copenhagen and Nikita Zelenkov of the Palaeontological Institute of the Russian Academy of Sciences, to discover what type of bird the humerus once belonged to.

The newly discovered species is officially named Mopsitta tanta, but it has been nick-named the Danish Blue Parrot.

 

 

Palaeontology 51 (3) , 575–582
Abstract: Two new fossil psittaciform birds from the Lower Eocene ‘Mo Clay’ (Fur Formation) of Denmark (c. 54 Ma) are described. An unnamed specimen is assigned to the extinct avian family of stem-group parrots, Pseudasturidae (genus and species incertae sedis), while a second (Mopsitta tanta gen. et sp. nov.) is the largest fossil parrot yet known. Both specimens are the first fossil records of these birds from Denmark. Although the phylogenetic position of Mopsitta is unclear (it is classified as family incertae sedis), this form is phylogenetically closer to Recent Pstittacidae than to other known Palaeogene psittaciforms and may, therefore, represent the oldest known crown-group parrot.

  • Pagina web dell’autore

Dr. David Waterhouse

maggio 16, 2008 Posted by | - Uccelli / Birds, 7 Paleocene, Europa, P - Ritrovamenti fossili | , , , , | Lascia un commento