Archaeopteryx had velociraptor-style feet

troy2000 · 12-04-2005, 02:03 PM

This has nothing to do with guns. I'm just fascinated by this sort of stuff:

WASHINGTON (Reuters) - An especially well-preserved specimen of Archaeopteryx shows the first known bird had feet like a dinosaur -- made not for perching but for running on the ground, scientists said on Thursday.

The first toe on the fossil turns inward, similar to a human thumb and most like the hunting dinosaurs known as deinonychosaurs -- notably the Velociraptor with its long claw for disemboweling prey.

Gerald Mayr of the Forschungsinstitut Senckenberg in Frankfurt, Germany, and colleagues at the Wyoming Dinosaur Center in Thermopolis, say their findings strengthen theories that birds descended directly from dinosaurs.

The 150 million-year-old fossil, found in Germany's Bavaria region, suggests the magpie-sized creature could hyperextend its second toe in a dinosaur-like way, the researchers report in Friday's issue of the journal Science.

"By all measures, it is a treasure," Peter Dodson of the University of Pennsylvania was quoted by Science as saying.

The feathered fossils were long believed to be representative of the first birds and this one now links Archaeopteryx to dinosaurs.

"Contrary to virtually all existing reconstructions of Archaeopteryx, the new specimen shows that the first toe was not fully reversed as in extant birds," the researchers wrote.

"Most workers consider Deinonychosauria to be the sister taxon of Aves, and the presence of a hyperextendible second toe in Archaeopteryx supports a close relationship between deinonychosaurs and avians."

Archaeopteryx had many bird-like features, such as feathered wings and a wishbone, but it also had distinctly reptilian traits, including jaws with teeth, a bony tail and claws on its fingers.

Addendum:

The Natural History Museum in London owns the first Archaeopteryx specimen to have been discovered, which it bought for £750 in 1862. Now, it is probably the most expensive fossil the museum possesses.

Twenty years ago, some scientists claimed that the fossil was a fraud made by sticking feathers into cement around a fossil reptile. But museum scientists soon proved the fossil genuine.

12-04-2005, 02:09 PM

Some researchcers have raised issues that may seem to make the theropod origin of birds difficult to support, but these difficulties are more illusory than substantial. One proposed difficulty is the gap in the fossil record between the first known bird (Late Jurassic) and the dromaeosaurs, probable sister group of birds (Early Cretaceous). This overlooks the blatant fact that other maniraptoran coelurosaurs, such as Ornitholestes, Coelurus, and Compsognathus, are known from strata of Late Jurassic age. If other maniraptorans were there, it logically follows that the ancestors of dromaeosaurs were there. Fragmentary remains of possible dromaeosaurs are also known from the Late Jurassic.
Other arguments, such as the putative differences between theropod and bird finger development, or lung morphology, or ankle bone morphology, all stumble on the lack of relevant data on extinct theropods, misinterpretations of anatomy, simplifying assumptions about developmental flexibility, and/or speculations about convergence, biomechanics, or selective pressures. The opponents of the theropod hypothesis refuse to propose an alternative hypothesis that is falsifiable. This is probably because there are no other suitable candidates for avian ancestors. "Thecodonts" are often promoted as such, but this is an obfuscatory, antiquated term for a hodgepodge of poorly understood and paraphyletic, undiagnosible reptiles. The problems cited by such opponents for theropods are often more serious for the "thecodont" pseudo-hypothesis. Finally, such opponents also refuse to use the methods and evidence normally accepted by comparative evolutionary biologists, such as phylogenetic systematics and parsimony. They rely more on an "intuitive approach," which is not a method at all but just an untestable gestalt impression laden with assumptions about how evolution must work.
The "controversy" remains an interest more of the press than the general scientific community. There are more interesting issues for scientists to explore, such as how flight performance changed in birds, what the earliest function(s) of feathers was(were), when endothermy arose in some archosaurs, which group of theropods was ancestral to birds, how theropod ecology changed with the acquisition of flight, why some bird groups survived the Cretaceous extinction of other dinosaurs, etc.
Without its feathers, Archaeopteryx looks much like a small coelurosaur such as a dromaeosaurid or troodontid.
The facts are resoundingly in support of a maniraptoran origin for birds; certainly a theropodan origin at the very least. So when you see a hawk diving to snatch a dove, or an egret darting for fish, or an ostrich dashing across the African savanna, know that you are gaining some insight into what the extinct dinosaurs were like. However, do note that extant (living) birds are quite different from extinct dinosaurs in many ways, so it's not safe to assume that all dinosaurs are the same. For that matter, extant birds are quite different from Jurassic and Cretaceous birds. Time passes, the environment changes... life evolves. Extant birds have been separated evolutionarily from the other coelurosaurian dinosaurs for some 150 million years, so they do look, act, and function quite differently, but science has shown us that they are closely linked by their common evolutionary history.

heilung · 12-06-2005, 06:13 PM

Bulletproof: Jeez..did you write that? Its nice having a fellow Paleontologist around so we dont get too bored with all that gun stuff. This is really a full service forum. What you got on human evolution? Heilung

12-06-2005, 07:36 PM

nah plagiarism at it's best/worst I don't believe in evolution

troylaplante · 12-06-2005, 08:27 PM

Quote:

Originally Posted by Bulletproof

I don't believe in evolution

I used to.

12-04-2005, 02:03 PM	#1
troy2000 Resident Armed Liberal Join Date: Dec 2004 Location: Southern California Posts: 10,017 Images: 9	Archaeopteryx had velociraptor-style feet This has nothing to do with guns. I'm just fascinated by this sort of stuff: WASHINGTON (Reuters) - An especially well-preserved specimen of Archaeopteryx shows the first known bird had feet like a dinosaur -- made not for perching but for running on the ground, scientists said on Thursday. The first toe on the fossil turns inward, similar to a human thumb and most like the hunting dinosaurs known as deinonychosaurs -- notably the Velociraptor with its long claw for disemboweling prey. Gerald Mayr of the Forschungsinstitut Senckenberg in Frankfurt, Germany, and colleagues at the Wyoming Dinosaur Center in Thermopolis, say their findings strengthen theories that birds descended directly from dinosaurs. The 150 million-year-old fossil, found in Germany's Bavaria region, suggests the magpie-sized creature could hyperextend its second toe in a dinosaur-like way, the researchers report in Friday's issue of the journal Science. "By all measures, it is a treasure," Peter Dodson of the University of Pennsylvania was quoted by Science as saying. The feathered fossils were long believed to be representative of the first birds and this one now links Archaeopteryx to dinosaurs. "Contrary to virtually all existing reconstructions of Archaeopteryx, the new specimen shows that the first toe was not fully reversed as in extant birds," the researchers wrote. "Most workers consider Deinonychosauria to be the sister taxon of Aves, and the presence of a hyperextendible second toe in Archaeopteryx supports a close relationship between deinonychosaurs and avians." Archaeopteryx had many bird-like features, such as feathered wings and a wishbone, but it also had distinctly reptilian traits, including jaws with teeth, a bony tail and claws on its fingers. Addendum: The Natural History Museum in London owns the first Archaeopteryx specimen to have been discovered, which it bought for £750 in 1862. Now, it is probably the most expensive fossil the museum possesses. Twenty years ago, some scientists claimed that the fossil was a fraud made by sticking feathers into cement around a fossil reptile. But museum scientists soon proved the fossil genuine. Last edited by troy2000; 12-04-2005 at 02:05 PM.

12-04-2005, 02:09 PM	#2
Logansdad Guest Posts: n/a	Objections to the theory of the dinosaurian origin of birds Some researchcers have raised issues that may seem to make the theropod origin of birds difficult to support, but these difficulties are more illusory than substantial. One proposed difficulty is the gap in the fossil record between the first known bird (Late Jurassic) and the dromaeosaurs, probable sister group of birds (Early Cretaceous). This overlooks the blatant fact that other maniraptoran coelurosaurs, such as Ornitholestes, Coelurus, and Compsognathus, are known from strata of Late Jurassic age. If other maniraptorans were there, it logically follows that the ancestors of dromaeosaurs were there. Fragmentary remains of possible dromaeosaurs are also known from the Late Jurassic. Other arguments, such as the putative differences between theropod and bird finger development, or lung morphology, or ankle bone morphology, all stumble on the lack of relevant data on extinct theropods, misinterpretations of anatomy, simplifying assumptions about developmental flexibility, and/or speculations about convergence, biomechanics, or selective pressures. The opponents of the theropod hypothesis refuse to propose an alternative hypothesis that is falsifiable. This is probably because there are no other suitable candidates for avian ancestors. "Thecodonts" are often promoted as such, but this is an obfuscatory, antiquated term for a hodgepodge of poorly understood and paraphyletic, undiagnosible reptiles. The problems cited by such opponents for theropods are often more serious for the "thecodont" pseudo-hypothesis. Finally, such opponents also refuse to use the methods and evidence normally accepted by comparative evolutionary biologists, such as phylogenetic systematics and parsimony. They rely more on an "intuitive approach," which is not a method at all but just an untestable gestalt impression laden with assumptions about how evolution must work. The "controversy" remains an interest more of the press than the general scientific community. There are more interesting issues for scientists to explore, such as how flight performance changed in birds, what the earliest function(s) of feathers was(were), when endothermy arose in some archosaurs, which group of theropods was ancestral to birds, how theropod ecology changed with the acquisition of flight, why some bird groups survived the Cretaceous extinction of other dinosaurs, etc. Without its feathers, Archaeopteryx looks much like a small coelurosaur such as a dromaeosaurid or troodontid. The facts are resoundingly in support of a maniraptoran origin for birds; certainly a theropodan origin at the very least. So when you see a hawk diving to snatch a dove, or an egret darting for fish, or an ostrich dashing across the African savanna, know that you are gaining some insight into what the extinct dinosaurs were like. However, do note that extant (living) birds are quite different from extinct dinosaurs in many ways, so it's not safe to assume that all dinosaurs are the same. For that matter, extant birds are quite different from Jurassic and Cretaceous birds. Time passes, the environment changes... life evolves. Extant birds have been separated evolutionarily from the other coelurosaurian dinosaurs for some 150 million years, so they do look, act, and function quite differently, but science has shown us that they are closely linked by their common evolutionary history.

12-06-2005, 06:13 PM	#3
heilung Senior Member Join Date: Aug 2005 Posts: 235 Blog Entries: 5	Bulletproof: Jeez..did you write that? Its nice having a fellow Paleontologist around so we dont get too bored with all that gun stuff. This is really a full service forum. What you got on human evolution? Heilung Last edited by heilung; 12-06-2005 at 06:23 PM.

12-06-2005, 07:36 PM	#4
Logansdad Guest Posts: n/a	nah plagiarism at it's best/worst I don't believe in evolution