Is Nanotyrannus A Separate Species Or Is It A Juvenile T Rex?

[jpc]

Pecks Rex has associated hand claws. I have a cast laying around somewhere.

[Killclaw]

I think the relatively extended length of the 'Nanorex' specimens would actually make a lot of sense if they were junior T-rex in the sense that it would help explain that eternal mystery of what the adult rexes actually did with those withered arms they couldn't reach their jaws with.

When they were juveniles and not big and robust to be capable of snatching whatever they wanted in their mouth they would have had more use for the arms and once they were larger and these became redundant they just stopped growing. Whether they would actually shrivel as they grow in absolute terms I wouldn't be so convinced on.

Of course what we really need is a wide sample of measurements for adult rex arms and claws that have been discovered and the few Nano specimens that exist so a proper scientific comparison can be done rather than anecdotal observations of individuals who have a predisposition to one interpretation or another (noone's holding their breath on that)

On a separate point has anyone ever explained why isolated Nano rex teeth are quite so abundant if there are so few skeletons found?

If they were juvenile rex teeth it would be more explicable again as they would be shedding these regularly as they evolved the monster size chompers they needed as adults.

[Auspex]

...On a separate point has anyone ever explained why isolated Nano rex teeth are quite so abundant if there are so few skeletons found?...

A couple factors:

>Theropods were tooth-shedding dentition factories, but had only one skeleton to contribute.

>Preservational bias. (teeth are tough)

>Collecting bias (small, isolated finds vs. skeletons requiring excavation).

[Killclaw]

A couple factors:

>Theropods were tooth-shedding dentition factories, but had only one skeleton to contribute.

>Preservational bias. (teeth are tough)

>Collecting bias (small, isolated finds vs. skeletons requiring excavation).

True but the point I was making is wouldn't the proportion of isolated teeth relative to number of skeletons found be the same between T-rex and Nano if they were different species living in the same area at the same point in time?

Am I wrong in thinking that there have been an awful lot more confirmed T-rex specimens discovered than the couple of Nanos in existence? As a collector though this doesn't seem to be reflected in their prevalence on the market.

[Troodon]

Interesting trip to the fossil show today. At George Heslep booth a collector dropped off his Nano Maxilla and a sign for him to display. FYI the teeth are real but have been placed in the jaw and not very well. Got a laugh from it.

I brought over Pete Larsen to look at it and have a discussion on Claws and Teeth. He confirmed that the maxilla was Nano and indicated that one from a Rex would not be V shaped like this one (see my white sideways V) and it would go straight up (see my dash marks). The opening in the maxilla (my arrow) is also much larger in a Rex.

I asked him about the bias that more Nano teeth are found over Rex. He agreed with that comment and said they do not know why but have several hypotheses.

1) There are simply more Nano's running around than Rex's. Typical of what you would expect in a apex predators relationships.

2) Nano jaws have a lot more teeth in them.

3) Rex teeth are simply more robust that the slender compressed Nano tooth and did not break as often. The design of Rex tooth being oval and stout can stand up to more abuse than the thinly compressed rectangular Nano tooth.

I took a picture of a dealers display case of T- rex teeth. The smallest is about 3/8" (1cm) and the largest is over 2" . Typical variety of rex teeth being sold and he had a lot more Nano teeth for sale with an equal distribution in size.

On Rex claws: Pete indicated he has never seen an associated pair of Digit 1 & 2 claws but he has seen both and they are slightly different. He said that Sue's claw is from Digit 1 "the larger claw" and 4 inches long. He does not believe that Rex hand claws exceed 4" and anything larger is simply Nano. I talked to a few diggers and the largest Nano they have seen is 5 1/2".

Edited February 1, 2016 by Troodon

[-Andy-]

On Rex claws: Pete indicated he has never seen an associated pair of Digit 1 & 2 claws but he has seen both and they are slightly different. He said that Jane's claw is from Digit 1 "the larger claw" and 4 inches long. He does not believe that Rex hand claws exceed 4" and anything larger is simply Nano. I talked to a few diggers and the largest Nano they have seen is 5 1/2".

You mean Sue's claw right?

[Troodon]

You mean Sue's claw right?

Thanks man, fixed it

[Troodon]

Am I wrong in thinking that there have been an awful lot more confirmed T-rex specimens discovered than the couple of Nanos in existence? As a collector though this doesn't seem to be reflected in their prevalence on the market.

Very few theropod skeletons have been found in the Hell Creek/Lance formation of any species why there are so few described in that fauna from skeletons. Preservation is just not that good for hollow and thin bones of smaller to mid size theropods. They've found more Adult T rex skeletons than all the theropod skeletons put together simply because bigger bones have a better chance of fossilizing. It's not an issue of Nano versus T rex its an issue of all the theropods including Juvie Rex's versus Adult Rex's. Edited February 1, 2016 by Troodon

[-Andy-]

Interesting trip to the fossil show today. At George Heslep booth a collector dropped off his Nano Maxilla and a sign for him to display. FYI the teeth are real but have been placed in the jaw and not very well. Got a laugh from it.

IMG_3858.JPGIMG_3859.JPG

I brought over Pete Larsen to look at it and have a discussion on Claws and Teeth. He confirmed that the maxilla was Nano and indicated that one from a Rex would not be V shaped like this one (see my white sideways V) and it would go straight up (see my dash marks). The opening in the maxilla (my arrow) is also much larger in a Rex.

IMG_3865.JPG IMG_3864AA.jpg

I asked him about the bias that more Nano teeth are found over Rex. He agreed with that comment and said they do not know why but have several hypotheses.

1) There are simply more Nano's running around than Rex's. Typical of what you would expect in a apex predators relationships.

2) Nano jaws have a lot more teeth in them.

3) Rex teeth are simply more robust that the slender compressed Nano tooth and did not break as often. The design of Rex tooth being oval and stout can stand up to more abuse than the thinly compressed rectangular Nano tooth.

I took a picture of a dealers display case of T- rex teeth. The smallest is about 3/8" (1cm) and the largest is over 2" . Typical variety of rex teeth being sold and he had a lot more Nano teeth for sale with an equal distribution in size.

IMG_3852.JPG

On Rex claws: Pete indicated he has never seen an associated pair of Digit 1 & 2 claws but he has seen both and they are slightly different. He said that Sue's claw is from Digit 1 "the larger claw" and 4 inches long. He does not believe that Rex hand claws exceed 4" and anything larger is simply Nano. I talked to a few diggers and the largest Nano they have seen is 5 1/2".

Didn't have time to comment on this today, beyond asking about Sue.

Wow, those fossils look good! I realize we still have so much more to learn about these amazing theropods. True that about Rex teeth being more robust. You know, I'm pleasantly surprised dealers are not jumping on the bandwagon and relabeling all their Nanos as T-Rex to make big bucks.

I've seen George Heslep's name show up a few times, and it seems he's often associated with high end fossils. I'm guessing he doesn't have a website or something to sell from?

[Troodon]

Wow, those fossils look good! I realize we still have so much more to learn about these amazing theropods. True that about Rex teeth being more robust. You know, I'm pleasantly surprised dealers are not jumping on the bandwagon and relabeling all their Nanos as T-Rex to make big bucks.

I've seen George Heslep's name show up a few times, and it seems he's often associated with high end fossils. I'm guessing he doesn't have a website or something to sell from?

Most of the dinosaur dealers at the show know the difference between the two species and try their best to have accurate ID's. Some of the best Dinosaur dealers do not have online sites and only do shows why it's important to be here. George is one of them and has been one of the top dinosaur dealers.

[-Andy-]

I just learnt there's a genuine juvenile T-Rex specimen named 'Baby Bob'. If properly studied, this could be the smoking gun to end the debate.

http://billingsgazette.com/news/state-and-regional/montana/fossil-hunter-claims-he-found-young-t-rex-near-jordan/article_db156e57-0cac-54df-8566-fff799e898f2.html

Most of the dinosaur dealers at the show know the difference between the two species and try their best to have accurate ID's. Some of the best Dinosaur dealers do not have online sites and only do shows why it's important to be here. George is one of them and has been one of the top dinosaur dealers.

I did a search. His collection of dinosaur material may beat even yours haha.

He even has Tarbo and Carnotaurus!

[Carcharodontosaurus]

I just learnt there's a genuine juvenile T-Rex specimen named 'Baby Bob'. If properly studied, this could be the smoking gun to end the debate.

http://billingsgazette.com/news/state-and-regional/montana/fossil-hunter-claims-he-found-young-t-rex-near-jordan/article_db156e57-0cac-54df-8566-fff799e898f2.html

I did a search. His collection of dinosaur material may beat even yours haha.

He even has Tarbo and Carnotaurus!

If this Baby Bob really is a juvenile T. rex and distinct from Nanotyrannus-type specimens, I agree with Thomas Carr that it needs to be in a museum. This could really be an important find.

And I've seen pictures of Heslep's material too. Cool stuff, but usually out of my price range.

[Troodon]

I just learnt there's a genuine juvenile T-Rex specimen named 'Baby Bob'. If properly studied, this could be the smoking gun

I know Bob, he is a good digger and owns a fossil company. They plan to unveil the baby Rex skull (4 years old) here at the Tucson Convention show Feb 11 and Bob will answer questions. It's exciting and may put an end to this debate BUT just like Carch said in the above post it needs to be studied by the right people. The dueling dinosaurs Nano should have ended the debate and it's still sitting in a warehouse.

Edit :This is an image of the skull they released. If it gets displayed will take photos for everyone to see. The Convention show is mostly minerals with very very few fossils fossil dealers. It's unfortunate it was not displayed at the main fossil shows but gets Bob the biggest pizzazz at this venue.

Edited February 2, 2016 by Troodon

[LordTrilobite]

That, is quite interesting. And it looks nothing like the Nano skull.

[Raptor Lover]

This may help, very worth watching!

[Killclaw]

Well that's one side of the argument anyway . NG kind of lost it credibility in the dinosaur world with the whole archaeoraptor saga so I wouldn't take their slant on the story at face value and the paleontologists featured staked their professional reputations long ago on the 'this is a whole new genus' argument, you can almost hear the desperation in their voice.

Its true that in any dinosaur ecosystem you would likely get more than a single therapod species, you can see that throughout the mesozoic age as in you might have an allosaurid, a raptor and a ceratosaur or Spinosaurid perhaps maybe living side by side but are we really expected to believe that when the culmination of tyrannosaur evolution developed right at the end of the dinosaur era in the mighty T-rex, a dwarf replica of it with subtle variations just happened to evolve in parallel to compete with it in the exact same time and place? And the only studied body specimen happens to be a juvenile when no T-rex juvenile specimens exist amongst the numerous skeletons found (so 100% vs 0 % juvenile/adult ratio if you take Jane to be a Nano)?

Sure there's the argument about the numbers of teeth but that can and has been explained, its not unique. Also he picks out the chunkiest, hugest adult T-Rex tooth he can find against the skinniest Nanorex to prove a point. What about the much smaller T-rex teeth we have all seen and the variations within one jaw and factor in that a juvenile tooth won't look like the biggest most robust adult tooth of any species you can find.

Then there's the arms, yes this 'Bloody Mary' has bigger arms than Sue but it clearly isn't double the size and they look structurally much the same. We'd need a far wider sample to say definitively that they can't be the same genus. A beast as sophisticated as a T-rex isn't going to hatch out fully formed and 11 years of age is likely a long way from the final form of its identity.

So if we can calculate the age of one specimen why not do so for this one? The owners seem very cagey about who they let look at and record their little pet and is it going to lose so much value extracting a sliver of bone to enable them to test its age? Until we find a definitively adult 'Nano' and/or a definitively juvenile T-rex (though of course perhaps we already have the latter) then this debate is just going to run and run.

Edited February 12, 2016 by Killclaw

[Raptor Lover]

Well that's one side of the argument anyway . NG kind of lost it credibility in the dinosaur world with the whole archaeoraptor saga so I wouldn't take their slant on the story at face value and the paleontologists featured staked their professional reputations long ago on the 'this is a whole new genus' argument, you can almost hear the desperation in their voice.

Its true that in any dinosaur ecosystem you would likely get more than a single therapod species, you can see that throughout the mesozoic age as in you might have an allosaurid, a raptor and a ceratosaur or Spinosaurid perhaps maybe living side by side but are we really expected to believe that when the culmination of tyrannosaur evolution developed right at the end of the dinosaur era in the mighty T-rex, a dwarf replica of it with subtle variations just happened to evolve in parallel to compete with it in the exact same time and place? And the only studied body specimen happens to be a juvenile when no T-rex juvenile specimens exist amongst the numerous skeletons found (so 100% vs 0 % juvenile/adult ratio if you take Jane to be a Nano)?

Sure there's the argument about the numbers of teeth but that can and has been explained, its not unique. Also he picks out the chunkiest, hugest adult T-Rex tooth he can find against the skinniest Nanorex to prove a point. What about the much smaller T-rex teeth we have all seen and the variations within one jaw and factor in that a juvenile tooth won't look like the biggest most robust adult tooth of any species you can find.

Then there's the arms, yes this 'Bloody Mary' has bigger arms than Sue but it clearly isn't double the size and they look structurally much the same. We'd need a far wider sample to say definitively that they can't be the same genus. A beast as sophisticated as a T-rex isn't going to hatch out fully formed and 11 years of age is likely a long way from the final form of its identity.

So if we can calculate the age of one specimen why not do so for this one? The owners seem very cagey about who they let look at and record their little pet and is it going to lose so much value extracting a sliver of bone to enable them to test its age? Until we find a definitively adult 'Nano' and/or a definitively juvenile T-rex (though of course perhaps we already have the latter) then this debate is just going to run and run.

Yeah you make some really good points. They need to compare the smallest teeth in a Rex's mouth to the "Nano" teeth that they find and see what they find. Also, if they can check the bones for Nano and determine that Jane is 11 years old, they should check the Rex specimens that have been found and if they find a big Rex that is around the same age as Jane, then that will show that they are different species. And it is kind of peculiar that they haven't found any small/young Rexes ever. I'm gonna try to find some videos against Nano being a new species so I can see more of the other side of argument.

[-Andy-]

Well that's one side of the argument anyway . NG kind of lost it credibility in the dinosaur world with the whole archaeoraptor saga so I wouldn't take their slant on the story at face value and the paleontologists featured staked their professional reputations long ago on the 'this is a whole new genus' argument, you can almost hear the desperation in their voice.

Its true that in any dinosaur ecosystem you would likely get more than a single therapod species, you can see that throughout the mesozoic age as in you might have an allosaurid, a raptor and a ceratosaur or Spinosaurid perhaps maybe living side by side but are we really expected to believe that when the culmination of tyrannosaur evolution developed right at the end of the dinosaur era in the mighty T-rex, a dwarf replica of it with subtle variations just happened to evolve in parallel to compete with it in the exact same time and place? And the only studied body specimen happens to be a juvenile when no T-rex juvenile specimens exist amongst the numerous skeletons found (so 100% vs 0 % juvenile/adult ratio if you take Jane to be a Nano)?

Sure there's the argument about the numbers of teeth but that can and has been explained, its not unique. Also he picks out the chunkiest, hugest adult T-Rex tooth he can find against the skinniest Nanorex to prove a point. What about the much smaller T-rex teeth we have all seen and the variations within one jaw and factor in that a juvenile tooth won't look like the biggest most robust adult tooth of any species you can find.

Then there's the arms, yes this 'Bloody Mary' has bigger arms than Sue but it clearly isn't double the size and they look structurally much the same. We'd need a far wider sample to say definitively that they can't be the same genus. A beast as sophisticated as a T-rex isn't going to hatch out fully formed and 11 years of age is likely a long way from the final form of its identity.

So if we can calculate the age of one specimen why not do so for this one? The owners seem very cagey about who they let look at and record their little pet and is it going to lose so much value extracting a sliver of bone to enable them to test its age? Until we find a definitively adult 'Nano' and/or a definitively juvenile T-rex (though of course perhaps we already have the latter) then this debate is just going to run and run.

Assuming Nanotyrannus is valid, it was thought to occupy a different niche from T-Rex, as it had proportionally longer limbs, and narrower teeth better than slicing than T-Rex's crushing ones. Along with its lighter body size and weight, Nano likely chase down smaller and faster prey. So no, Nano isn't a dwarf replica of Rex with subtle variations.

As you said, the only studied body specimen is Jane. But in terms of unstudied specimens, we have Baby Bob.

Even small T-Rex teeth are distinctly thicker and rounder than Nano ones. You can look at Troodon's(TFF member) as reference.

And Bloody Mary didn't need to have arms double the size of Sue's; the mere fact BM has bigger arms is indication enough. The burden on proof is now on you to find theropods of the same species with differently sized arms.

But yes, I agree on the last part: We need a definitively adult Nano and a definitively juvenile T-Rex in scientist hands to end this debate.

[Troodon]

Then there Bob, saw baby Rex yesterday. Will post a full report as soon has I get my Internet up an running

[-Andy-]

http://biodiversity.ku.edu/node/1665

'Teenage theropod no more!' by Josh Schmerge

[Auspex]

The morphological differences between a "Nano" and a "Rex" strongly suggest a different prey base; the evidence is telling us that they did not compete. That said, it is still possible for them to be the same species: among modern raptors (most notably the accipiters), the males and the females of the same species are constructed so as not to compete with each other for prey.

[Raptor Lover]

That, is quite interesting. And it looks nothing like the Nano skull.

Agreed!

[hxmendoza]

In my opinion one just needs to look at the hand claws to see the difference. The Nanotyrannus Claw that I just added to my collection appears to be from an adult (biggest I've seen) and measure 5" straight across. The T-rex Claw is a replica from an adult Rex from the Black Hills Institute and measures 4" and is typical of others I've seen. The differences other than the obvious length is that the Nano is much more slender and not has re-curved and it's double the width. The proximal end on the Rex claws are also wider and more compressed and overall its a more compact claw. The argument that I've heard is that the claws get smaller as the animal gets older. I think that's weak, one just needs to look at what happens in other tyrannosaurs or theropods, they get larger with age. Andy I do not have measurements on the arms.

Nanotyrannus 5" hand claw

NanoClaw_edited-1.jpg

T-rex replica hand claw 4"

rexmanusclaw_004.jpg

Here is a photo I took of the arm from the Dueling Dino Nanotyrannus (Left) and the T-rex arm from Sue. The bones are different.

Dulers Arm.jpgRexarm.jpg

Troodon. You cannot compare that Nanotyrannus hand claw with that cast claw.

First of all, the cast claw is not Stan's. Stan was not found with any manus material. That was an isolated find. And both Pete and Neal Larson told me that years ago (I own the same cast).

Secondly. That cast is of a Digit I claw. The "Nanotyrannus" hand claw is a Digit II claw. I know this because I have a cast of the Juvenile Gorgosaurus arm and claws from the Tyrrell Museum. I also have a cast of the partial Digit I claw found with Sue. I have held and seen all four claws from the Children's Museum of Indianapolis Gorgosaurus skeleton when Pete Larson allowed me access to them years ago up at BHI. I have seen Daspletosaurus hand claws. And Tarbosaurus hand claws. Tyrannosaurid hand claws all follow the same Bauplan. Even the Dueling Dinosaurs Tyrannosaurid's hand claws follow the same morphological features.

The Digit I claw is more robust proximally and claw tip more recurved. It has a prominent and more robust flexor tubercle.

The Digit II claw is more gracile overall. Less recurved (more like the digit II and III claws of Strutiomimus in curvature) and less robust proximally.

Your Tyrannosaurid indeterminate hand claw in your JRF post is a Digit I (thumb) claw. Your picture in your previous postings of your "Nanotyrannus" hand claw is a digit II claw.

On that note. Unless these claws are found in association or articulation with a T. rex or Nanotyrannus, they CAN ONLY be referred to as Tyrannosaurid sp. indeterminate claws.

Below is a Tarbosaurus Digit I claw:

These are the hand claws (Two Digit I claws and one Digit II claw) from the Tyrannosaurid Petey, at the Burpee Museum:

This is a JRF Digit I claw from the AMNH:

These are the Digit I (Bottom) and Digit II (top) claws from the Indianapolis Children's Museum Gorgosaurus:

This is a Daspletosaurus Digit I claw from the Two Medicine Formation:

This is a Tarbosaurus Digit II claw:

Tyrannosaurid Digit I claws all have very similar morphologies across the board. Same goes for Tyrannosaurid Digit II claws.

Edited February 17, 2016 by hxmendoza

[Troodon]

I never said the claw is from Stan just a typical hand claw of a rex.

Just trying to make a point that Nano hand claws reach +5 inches and the Sue's hand claw is 4". Pete has see both digits on a Rex hand and said none exceed 4. You cannot even consider the Campanian claws their from different species and time.

[hxmendoza]

I never said the claw is from Stan just a typical hand claw of a rex.

Just trying to make a point that Nano hand claws reach +5 inches and the Sue's hand claw is 4". Pete has see both digits on a Rex hand and said none exceed 4. You cannot even consider the Campanian claws their from different species and time.

Sue's Digit II claw is unknown. Therefore he cannot say that it's bigger than Sue's claw. Individual variation cannot exclude Sue's Unknown Digit II claw as being 5 inches either, or even bigger.

Plus there is evidence via skull and isolated elements of T. rex individuals as being even larger than Sue.

Edited February 17, 2016 by hxmendoza