The first single-fingered dinosaur

Jan 24, 2011
Artist's impression of Linhenykus monodactylus. © Julius T. Csotonyi

(PhysOrg.com) -- A new species of parrot-sized dinosaur, the first discovered with only one finger, has been unearthed in Inner Mongolia, China.

Scientists named the new dinosaur Linhenykus monodactylus, after the nearby city of Linhe. The work is published online today in (PNAS).

The new dinosaur belongs to the Alvarezsauroidea, a branch of the carnivorous dinosaur group Theropoda. Theropods gave rise to modern birds and include such famous dinosaurs as Tyrannosaurus and Velociraptor.

An international team of palaeontologists found the fossil preserved in rocks of the Upper Cretaceous Wulansuhai Formation, which is located near the border between Mongolia and China. The formation dates to 84-75 million years ago and has yielded a rich trove of vertebrate fossils including the recently discovered theropod Linheraptor exquisitus. The authors uncovered a from the site, which included bones of the , the forelimb, a partial pelvis and nearly complete hind limbs.

Linhenykus most likely grew to a couple of feet tall and weighed only as much as a large parrot. The new theropod is unusual in having just one large claw, which may have been used to dig into insect nests, on each of its hands. This feature makes the specimen the only known dinosaur with one finger, and highlights the wide variety of evolutionary modifications of the hand that existed in different theropods.

Michael Pittman of the Department of Earth Sciences at University College London, co-author and discoverer of the specimen said: "Non-avian theropods start with five fingers but evolved to have only three fingers in later forms. Tyrannosaurs were unusual in having just two fingers but the one-fingered Linhenykus shows how extensive and complex theropod hand modifications really were."

Most have three fingers on each hand, but in most alvarezsauroids other than Linhenykus the two outer fingers are reduced to tiny, apparently useless structures. The presence of only one finger in Linhenykus, which is hypothesized to be a relatively primitive alvarezsauroid, shows that these vestigial fingers were not present in all members of the group. The reasons for the loss of the two outer fingers in Linhenykus are unclear, and their disappearance may simply reflect the fact that they were no longer being actively maintained by natural selection

Jonah Choiniere, co-author and co-discoverer of the specimen from the Division of Paleontology at the American Museum of Natural History said: "Vestigial structures, like legs in whales and snakes, may appear and disappear seemingly randomly in the course of evolution. Linhenykus highlights the vestigiality of the outer fingers of advanced alvarezsauroids and underscores the complexity in evolution of these vestigial fingers."

Linhenykus lived with closely-related and similarly-sized theropod dinosaurs, but the specializations of its skeleton may reflect differences in behaviour or foraging strategy. Linhenykus also lived alongside small mammals, lizards, clubbed dinosaurs (ankylosaurs) and horned (ceratopsians).

Explore further: Taung Child's skull and brain not human-like in expansion

More information: 'The first known monodactyl non-avian dinosaur and the complex evolution of the alvarezsauroid hand' is published in Proceedings of the National Academy of Sciences.

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User comments : 20

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geokstr
3.9 / 5 (11) Jan 24, 2011
Well, this finally clears up a long-standing evolutionary mystery that has puzzled scientists for ages. This new dino discovery is obviously the ancestor of homo sapiens newyorkericus, who also are known to have only one finger.
jmcanoy1860
3 / 5 (2) Jan 24, 2011
Well, this finally clears up a long-standing evolutionary mystery that has puzzled scientists for ages. This new dino discovery is obviously the ancestor of homo sapiens newyorkericus, who also are known to have only one finger.


Haaw!!!!
Parsec
3 / 5 (6) Jan 24, 2011
Well, this finally clears up a long-standing evolutionary mystery that has puzzled scientists for ages. This new dino discovery is obviously the ancestor of homo sapiens newyorkericus, who also are known to have only one finger.

geoskstr - I would never in a million years have imagined I would give you something other than a '1' rating for your posts.

Thats funny.
eigenbasis
1 / 5 (2) Jan 24, 2011
he was giving the whole ancient world the finger!
Nomen_Dubium
not rated yet Jan 24, 2011
Linhenykus is not the first one-fingered dinosaur discovered. Mononykus and Parvicursor, also Alverezaurids, were described in 1993 and 1996, respectively.
nuge
not rated yet Jan 25, 2011
Linhenykus most likely grew to a couple of feet tall and weighed only as much as a large parrot.


Wow, not much of a dinosaur, is it? Sounds like a human being would easily be able to best this creature physically. I wonder what its prey were, seeing as it is supposed to be a carnivore?
lexington
5 / 5 (1) Jan 25, 2011
How do they know they didn't just miss the other fingers? Facts. I demand facts!
Blakut
not rated yet Jan 25, 2011
Also, who fingered it?
kevinrtrs
1 / 5 (6) Jan 25, 2011
Theropods gave rise to modern birds and include such famous dinosaurs as Tyrannosaurus and Velociraptor.

Pure guess-to-fact of course - just how do they KNOW this happened? They don't, they can only surmise - "it's possible", "maybe like this", "possibly this", "probably that" etc. Besides which, just how many fingers does a bird have? And how many feathers have they discovered on the Linhenykus monodactylus?

kevinrtrs
1.5 / 5 (8) Jan 25, 2011
"Vestigial structures, like legs in whales and snakes, may appear and disappear seemingly randomly in the course of evolution.


Just like the vestigial tonsils which were diabolically and needlessly surgically removed in millions of children with colds and flu symptoms.

Now of course man's knowledge has evolved to the point where we know that the tonsils play a vital role in the development of the immune system in small children.

Another example where man's knowledge evolved being that of the vestigial appendix, which is a store house of some importance.

So evolution does occur at times - man's knowledge is showing a continuing evolution, hopefully towards sanity.

One day it might evolve to the point of realizing that the Darwinian single ancestor evolutionary theory is just so much junk.
Ethelred
3.7 / 5 (6) Jan 25, 2011
So evolution does occur at times - man's knowledge is showing a continuing evolution, hopefully towards sanity.
Indeed. YOU might evolve your thinking to the point that you stop believing in a book that has the Egyptians drowned in the middle of the time they were building the pyramids.

Nahh. You will NEVER deal with reality.

One day it might evolve to the point of realizing that the Darwinian single ancestor evolutionary theory is just so much junk.
See. Never.

Fool me Kevin. Join reality. Give up on that ancient book written by ignorant men.

Or just tell us when the Flood occurred.

Ethelred
panorama
5 / 5 (1) Jan 25, 2011
I wonder what its prey were, seeing as it is supposed to be a carnivore?

Maybe it ate the eggs of Sauropods. Still a carnivore, just opportunistic.
baudrunner
1 / 5 (1) Jan 25, 2011
Dogs have that rubbery claw-like thing on their forelegs. It's for grasping the female during coitus. It's likely that those single claws/fingers evolved for the same purpose - for that matter, arms and hands in general.

And ethelred: I thought I told you about the flood. It happened 13,950 years ago, when a massive sheet of ice the size of a continent broke off the Antarctic ice shelf. Oh, yeah, you don't like being told things, you just like expressing your distaste for other posters.
Terrible_Bohr
5 / 5 (3) Jan 25, 2011
Pure guess-to-fact of course - just how do they KNOW this happened? They don't, they can only surmise - "it's possible", "maybe like this", "possibly this", "probably that" etc. Besides which, just how many fingers does a bird have? And how many feathers have they discovered on the Linhenykus monodactylus?

That's how science works - by generating models that explain observations. The fact that the models can be changed in the face of new discoveries means that they are more or less saying "probably that". The thing is that models also make predictions; predictions that make your computer work, for one thing. I don't see how this is hard for your to accept; your magic book requires you to believe in the most outrageous claims ever made with no evidence whatsoever.

I don't see why Linhenykus monodactylus has to have feathers to preserve evolution's integrity. There was no claim that this dinosaur was the direct ancestor of modren birds.
Ethelred
3 / 5 (2) Jan 26, 2011
I thought I told you about the flood
You made some ridiculous unsupported claims.
It happened 13,950 years ago, when a massive sheet of ice the size of a continent broke off the Antarctic ice shelf
It is just as ridiculous this time. There is NO evidence to support the claim as there would be MORE evidence in places closer to the Ice Shelf. All the crap you call evidence was in the Middle East, wasn't evidence for a flood, and the blocks were made by ROMANS in thousands of years later than you claimed.
Oh, yeah, you don't like being told things
No. I like being told REAL things I don't know about. I thank people for it. YOU don't like being told that your ideas are full of crap. With no evidence to support them.
you just like expressing your distaste for other posters.
Nonsense. I am just pointing out that unsupported nonsense is silly. And your is right up there with Oliver's Iron-Neutron Sun. Totally without evidence and in denial of actual physics.

Ethelred
baudrunner
1 / 5 (2) Jan 27, 2011
Ethelred:

Again, you are proving my point, which is that you talk more than you read. All of the Earth's greatest scientific thinkers have concluded that the Romans, or for that matter, any of the builders of earth's ancient civilisations, could NOT POSSIBLY have moved and placed those giant stone blocks in Baalbek. In fact, it is generally agreed that today's engineers couldn't even do it. The Roman temple to Jupiter was constructed more recently upon that platform, which is described in ancient Sumerian cuneiform tablets that predate Roman history by thousands of years. You are not so much a skeptic as an arrogant denier.

Skeptic_Heretic
not rated yet Jan 27, 2011
Again, you are proving my point, which is that you talk more than you read. All of the Earth's greatest scientific thinkers have concluded that the Romans, or for that matter, any of the builders of earth's ancient civilisations, could NOT POSSIBLY have moved and placed those giant stone blocks in Baalbek. In fact, it is generally agreed that today's engineers couldn't even do it.

You'd probably want to have a chat with Mark Lehrner, Roger Hopkins, and Vince Lee in that eventuality. Would you like their email addresses or can you grab them off google?
baudrunner
1 / 5 (1) Jan 27, 2011
Skeptic Heretic: Those fellows performed experiments to determine that stone blocks up to 10 tons could be moved using enough men and wooden rollers. They also theorized on the method used to move 300 ton blocks but did not perform the experiments, which were too challenging for them.

I am not aware of any theorizing by them about what means may have been employed to move the foundation blocks in Baalbek, which form the platform on which the temple was built by the Romans 2,000 years ago. The foundation existed long before that time. The larger of those stones weigh in excess of 1,500 tons! Yes, up to 1,600 tons! Any ideas?

About that chat, I would like that, yes.

Ethelred
1 / 5 (1) Jan 30, 2011
: Those fellows performed experiments to determine that stone blocks up to 10 tons could be moved using enough men and wooden rollers.
Succeeded too. They couldn't test really large blocks because they didn't have a Roman budget and labor is expensive these days and cheap for the Romans.

I am not aware of any theorizing by them about what means may have been employed to move the foundation blocks in Baalbek
No reason to think that the same basic methods wouldn't have scaled up.

was built by the Romans 2,000 years ago.
Not quite that long ago but they DEFINITELY handled blocks over 100 tons as there is one that used to be 19 meters up on top of columns.

In fact, it is generally agreed that today's engineers couldn't even do it
Generally agreed by people that don't want to find real answers.

More
Ethelred
1 / 5 (1) Jan 30, 2011
. The larger of those stones weigh in excess of 1,500 tons! Yes, up to 1,600 tons!
NO. Numbers pulled out of the ass of an Ass are not real. The real number is 800 tons an that is a mere eight time stuff the Romans not only carved and moved but also put 19 meters high.

And of course NOTHING you have said shows any evidence of a flood there or anywhere else between there and the Straits of Gibraltar. Something you keep ignoring. You don't have any evidence to support you. All you have is a dubious claim that the Romans couldn't have done it and bogus numbers for the age of the platform and bogus weights for the rocks used in the platform.

Ethelred