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Updated 1/17/20

 

I've taken a pretty firm position on the validity of Nanotyrannus ever since I spent some time looking at the Dueling Dinosaurs shortly after they were discovered.   Subsequent to that, new information that I've become aware of just cemented my position.   I'm interested in understanding the "truth" and have no problem looking at all available specimens that are in private hands or museums.   The optics are very clear to me and I have difficulty understanding the debate.  Collectors need to form their own opinion on this but I would like to share with you why I believe its a valid species.     

 

A recent paper that CLAIMS that Jane and Petey are still growing that they have to be T Rex is ridiculous. WHY? Just because they are growing.... We have no idea what stage in their life cycle they were and obviously they are not adults.  Nano's grow, we have no idea how large, and have similar life cycles has do T rex's.  If it was not for all the other supporting evidence to validate Nanotyrannus it might make sense but the claim is nonsensical.

 

I present here several examples supporting my case, many others exist but will leave it at this.

 

You always hear we need see sub-adult/baby specimens of Trex so a comparison can be make against Nanotyrannus claimed specimens.   Shocking but some specimens do exist in institutions and private hands.   Included in this discussion are a couple of examples of these specimens other are out there some in private hands and hopefully will be published.  

 

Jaws

Case in point here is a jaw of a  Baby T rex in private hands.  Its only 35 cm wide.   Paleontologists involved in this debate are very well aware of its existence.

This cast in my collection is of one of 6 ever made from the original.

5c87dadc5c642_ReplicaJaw2.thumb.jpg.8f34864bc57a114f634f4b1c474eeedb.jpg

 

Top jaw: T rex (BHI6439),  White jaw: Nanotyrannus (BMPR2002.4.2)

Note that the length of the tooth row is nearly identical,

Top jaw contains 13 circular alveloi typical of adult T rex's while the white jaw contains 17 rectangular alveloi typical of what is described as Nanotyrannus. 

Morphology of the teeth is classic for Trex: fat, oval and robust.  Morphology of white jaws teeth is classic for Nanotyrannus: rectangular, lean and more gracile.

 

DYWFxYVVoAA9TXY.jpeg.4bab06fa3c2f5674c0f1a07a1031f381.jpeg

 

 

There are a number of other morphological differences that Pete Larsen has identified with the jaws but the eye test should be enough for this discussion

DYWD2QjW4AAJeSt.jpeg.3ea588072a5c309db3de1fe484b933c4.jpeg

 

DYWD2QZWkAAeyVG.jpeg.5c1b3d3084acc8cb083752bd92c0281b.jpeg

 

Compare the widths for both of these species, there is no comparison its pretty obvious how robust one is over the other. 

DYWFxWMUMAEp2Jj.thumb.jpeg.104891d686c4b419a0b06397639267b1.jpeg

 

ARMS

If the Jaws were not enough here are the arms and claws.

 

Here is a sub-adult Trex arm (UCRC-PV1) housed at the University of Chicago (Paul Sereno).  Paleontologists involved in this debate are very well aware of its existence.

 

This is the only complete Trex arm and hand that has been found to date and articulated including the scapula and coracoid and partial skeleton  including vertebrae.   The bones including the claws compare well with those of known adult T rex and the vertebrae are about twice the size of Jane (Nanotyrannus)

DYIChJBWsAENDNh.jpeg.77b3267e9302387028110372ce4c7ed6.jpeg

 

DYH6IhKXcAAE6RU.jpeg.1053b4075485c87f4840b659e8135b42.jpeg

 

 

Added (1/7/20)

 

Pete Larsen : "Adult and sub adult hands of T.rex (A, B and D) compared to the hand of Nanotyrannus (C), BHI 6437, which has a skull length of 610mm, the same as Jane BMRP2002.4.1."

 

How can the rational paleontologists support the papers claim

B is a Sub-Adult T rex (UCRC PV1)  who's bones look just like D from an adult T rex.(MOR 555)

C bones a Nanotyrannus is larger with very different bone morphology 

 

ENsLH2SWwAAKcw5.jpg.89e1c6d4c1e3fc00bf35a7424487827e.jpg

 

 

Every known bone from the hand of a Nanotyrannus is larger than and morphologically different from every known hand bone of adult or sub-adult T rex.  I'm not aware of any other Tyrannosaurid where juvie and adult arms become smaller as the animal ages.

 

Here is an sketch comparing the two to see how different the bones are.  Pete Larsen also points out that "Animals do not change the orientation of semicircular canals, imbedded within solid bone, as they grow"

Arms.thumb.jpg.e0017645cc51a34bb089c0e2c53e8deb.jpg

 

Compare the long bone of Nanotyrannus with arrow to the one below on T rex  Sue

IMG_2108r.thumb.jpg.e866d3ae659d9e330007d5ce12b7c327.jpg

 

Sue -  Carpal is much shorter and with a different morohology...

20190312_080222.thumb.jpg.48f19b733e27fbd0e975fbccc02e93da.jpg

 

Here is a comparison of a carpal digit I  Wyrex (Top),  Nanotyrannus (Middle), Sue (Bottom) 

Both Trex's have a larger bulge at the end of the bone.  Very different morphology.  You can argue ontogenetic changes but the robustness is present in the arm from above.

Matacarpal.thumb.jpg.0f9d1c1a1701b3574b0c90984472c9f1.jpg

 

 

Added 1/17/20

 

From left to right :  Gorgosaurus TVM 2001.89.1, Nanotyrannus BHI-6437, adult T.rex MOR-980, and sub adult T.rex TCM 2001.90.1.

Your can see on similarities with the two on the right both of Trex of different ages.  Interesting though the paleontologists said the younger one should be longer :headscratch:

 

Capture.thumb.JPG.9b3da54eea11c4f3e938ea72ce925f36.JPG

 

 

 

 

CLAWS

Lets move on to the claws

 

Top T rex  Digit I - Sue (Left), Digit II - Victoria (Right)

Bottom Nanotyrannus - Digit I (Left), Digit II (Right) (BMRP 2006.4.4) (Petey's)

 

Morphology is very different and Digt II of Victoria is very similar to that of the sub adult claw see below.

DYH9RbpX4AMj5sd.jpeg.227d6b8c91d71cfa1cb7fc5f47228506.jpeg

 

Sub Adult Trex claw Digit II,  5 cm .. compares quite well to adult Victoria not Nanotyrannus

 

DYH60CxX0AI4fY9.thumb.jpeg.693d8cdcdcf18319a9d62693316d8503.jpeg

Lots of the photos provided by Peter Larsen 

 

Added 1/7/20

Pete recently posted

"But wait, you say. wasn’t Jane still growing? She certainly was, comparing Jane size BHI-6437’s manus claws ( Brown) to Petey’s (BMRP 2006.1.1) (White). The question I have is: when do the hands stop growing so they can shrink (a lot) and then begin growing again?"

 

ENsLIxlWsAEq4nn.jpg.0ba229baae613ddd34ac4f891bd28625.jpg

 

 

Braincase

 

One last item to present is the Witmer Labs study on Tyrannosaurid braincases...it clearly demonstrates that there is a difference between T-rex and Nanotyrannus.

 

Conclusion on the Cleveland "Nano" skull

"Given the obvious closeness of CMNH 7541 and BMR P2002.4.1 "Jane", it would likely have been taxonomically decisive. Our data on CMNH 7541 may be taken as evidence for the validity of N. lancensis on the grounds that it is ‘‘too different’’ from T. rex. However, we are hesitant to argue that the debate over its status is settled for the simple reason of sample size. CMNH 7541 presents one specimen—one highly divergent specimen. Although we see no clear signs of distortion or pathology in the braincase, its divergent nature concerns us, and we maintain that the possibility remains that future discoveries will show CMNH 7541 to be aberrant. For that reason, we urge caution and continue to regard the specimen’s status as open"

 

https://onlinelibrary.wiley.com/doi/full/10.1002/ar.20983

 

New Insights Into the Brain, Braincase, and Ear Region of Tyrannosaurs (Dinosauria, Theropoda), with Implications for Sensory Organization and Behavior

First published: 26 August 2009

 

Screenshot_2019-03-28-02-38-18.thumb.jpg.03c1a5f4f1eaa909acb64abb681b626e.jpg

Screenshot_2019-03-28-02-39-46.thumb.jpg.11bd53ffc1af89511474b074f5e87931.jpg

 

It's unfortunate that the skeleton Jane does not have the two skeletal areas discussed in this topic: Arms and Braincase.  More reason for the Dueling Dinosaur Nanotyrannus to be studied it's almost a complete skeleton.

 

The End...:D

 

 

 

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:Smiling:  :notworthy:

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Tidgy's Dad

Thank you. 

Very interesting. :)

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ziggycardon

Thank you for posting this! 
Very informative piece on a very interesting topic :) 

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fossilsonwheels

Great post. We did not talk about Nano yesterday with the students. We did not have time but I think it will be a subject for discussion in  our next program. This is very helpful.

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Fantastic post Frank with a lot of factors featured and illustrated . Looking at the  evidence it seams very much to me like Occam's razor would favour Nanotyrannus .  Thank you.

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Again thank you Troodon for putting your post together in such a way even the lamest in in vertebrae paleontology can understand, personally I have seen this for many years and don't fully understand why this is a debate at all, and with this post and evidence gathered shows the statistical significance in differences between the two species.

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Dracorex_hogwartsia

It all looks pretty compelling. Is there any theory on where Nanotyrannus came from? Nanotyrannus is only found in the Hell Creek?  What is the lineage for Nanotyrannus? Have any pigmy tyrannosaurs been found in Mongolia? 

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40 minutes ago, Dracorex_hogwartsia said:

It all looks pretty compelling. Is there any theory on where Nanotyrannus came from? Nanotyrannus is only found in the Hell Creek?  What is the lineage for Nanotyrannus? Have any pigmy tyrannosaurs been found in Mongolia? 

No for the lineage for both Trex or Nanotyrannus.  Material is found in the HC and Lance Formations but probably exists in all late Maastrichtian deposits in North America particularly where Trex material has been found.   Not sure about the word pigmy tyrannosaurs but you can draw an analogy to Tarbosaurus and Alioramus of the very late cretaceous of Mongolia 

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This is something I’ve been wondering myself for a long time, looks pretty clear to me now. Thank you for the detail and visuals Frank. 

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Thanks for this post :) I'm not a paleontologist but I never really understood this discussion and why this seems to be such a big deal. Why keep people defending this point so much? 

 

I can just throw in the juvenile T-Rex we have here in South Germany :) I posted that last year.

 

It is now on permanent display at the Dinopark Altmühltal in the center of Bavaria. 

For more info on the location: CLICK

 

 

This is a young T-Rex (not seeing any Nanotyrannus here...):

 

20180722_1031561111.jpg.1b65c64a69bec821824787d0fac7faea.jpg

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Dracorex_hogwartsia
22 hours ago, Troodon said:

No for the lineage for both Trex or Nanotyrannus.  Material is found in the HC and Lance Formations but probably exists in all late Maastrichtian deposits in North America particularly where Trex material has been found.   Not sure about the word pigmy tyrannosaurs but you can draw an analogy to Tarbosaurus and Alioramus of the very late cretaceous of Mongolia 

I meant to say dwarf, sorry about that :-) I know the fossil record is a spotty thing so you can't really go by that but it would be nice if you could trace the lineage of Nanotyrannus back to something. T. rex and Nanotyrannus both show up in the Hell Creek/Lance formation at around the same time. I thought we could trace back the lineage of T. rex , you say no. Who is the ancestor of Nanotyrannus? Nobody seems to know.

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David in Japan
7 hours ago, Abstraktum said:

Thanks for this post :) I'm not a paleontologist but I never really understood this discussion and why this seems to be such a big deal. Why keep people defending this point so much? 

 

I can just throw in the juvenile T-Rex we have here in South Germany :) I posted that last year.

 

It is now on permanent display at the Dinopark Altmühltal in the center of Bavaria. 

For more info on the location: CLICK

 

 

This is a young T-Rex (not seeing any Nanotyrannus here...):

 

20180722_1031561111.jpg.1b65c64a69bec821824787d0fac7faea.jpg

20180726_18385711111.jpg.e3d5909d02007ec3d920fc1658c0d5f4.jpg

20180722_103258sjdhgsth.jpg.7b394b47d25acbab41bb0f8984d58ddf.jpg

 

 

 

I don't want to enter the debate because I do not have any answer but this is MOR 6625 also called Chomper and it is a T-rex juvenile. 

 

chomper.jpg.9186118b9605f2471ece2ae18dad160f.jpg

 

 

 

 

 

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DPS Ammonite

Thanks Frank for all your informative posts. You get the E. F. Hutton Award: when you talk everyone listens.

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3 hours ago, David in Japan said:

 

I don't want to enter the debate because I do not have any answer but this is MOR 6625 also called Chomper and it is a T-rex juvenile. 

 

chomper.jpg.9186118b9605f2471ece2ae18dad160f.jpg

 

 

I completely see your point.

I looked into this topic and the skull as seen on the picture is reconstructed and they used Janes skull for some parts. Chomper (MOR 6625) is only known from jaw fragments. 

Some quotes about MOR 6625:

 

Quote

this model is based on some fragmentary lower jaw bones (MOR 6625) of the smallest/youngest known specimen of T. rex, which goes by the nickname "Chomper." Ryan Ridgely and I used MOR 6625 as the basis for overall skull size, which is only about 13" long. Notice that Chomper's fossil chompers are actually included in the model! We restored the rest of the skull by digitally regressing ("de-growing") the skull of Jane (BMR P2002.4.1), an older but still quite young individual, supplemented with details from the slightly smaller skull of Tarbosaurus that we published on in 2011. So, yes, it's a composite of multiple specimens and species, but the reality is that baby tyrannosaurines probably all resembled each other very closely.

 

Quote

The model retains some Jane features (like number of teeth), because Jane was our digital source. If the resulting science dictates changes in the model, we can make those changes

 

Does anyone have pictures of the jaw remains of Chomper? Would be interessting to compare them to the jaw pieces of this Thread. 

The skulls is 13 inches or 35 cm and that means the whole skull is as long as the jaw fragment in this Thread. 

 

Is there more info on that MOR 6625? The reconstructed skull is now 4 years old. Any update?

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Wonderful post Troodon. Thank you for compiling this info.

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5 hours ago, Abstraktum said:

Some quotes about MOR 6625

Does anyone have pictures of the jaw remains of Chomper? Would be interessting to compare them to the jaw pieces of this Thread. 

The skulls is 13 inches or 35 cm and that means the whole skull is as long as the jaw fragment in this Thread. 

 

Is there more info on that MOR 6625? The reconstructed skull is now 4 years old. Any update?

Chompers fragments are shown below, pretty rough, and I believe 3D reconstructed by Witmer Labs and then made part of the exhibit..  If I compare the baby jaw fragments of Chomper to the replica jaw in my collection it has all the appearence of Nanotyrannus but would like to see more views of it before I draw a final conclusion.  My replica baby jaw is basically as it was found no teeth were added.

 

It's amazing what can be reconstructed with today's technology.  

Screenshot_20190314-035432.thumb.jpg.e45a7b53258c9392c42126f33dc4c640.jpgScreenshot_20190314-035555.thumb.jpg.8bfd62fac7acd7f918dbee4c6021c572.jpg

 

@David in Japan

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@-Andy-  @JohnBrian @Dracorex_hogwartsia @Masp @Abstraktum @Praefectus @ynot @Tidgy's Dad @LordTrilobite

@DPS Ammonite  @Haravex @Bobby Rico @JohnBrewer  @ziggycardon @fossilsonwheels

 

Thank you for your feedback.  Hopfully this provided you and others some idea of why I take the position I do on this cool dinosaur that really needs to have its own identity. 

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18 minutes ago, Troodon said:

Chompers fragments is shown below, pretty rough, and I believe 3D reconstructed by Witmer Labs and then made part of the exhibit..  If I compare the baby jaw fragments of Chomper to the replica jaw in my collection it has the appearence of Nanotyrannus but would like to see how wide it is before I draw a final conclusion.

 

 

Thank you for the pictures and additional information. Would be great if one could compare the diffrent jaw fragments of young T-Rex and Nanotyrannus directly with each other, like you did in this post. :) 

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3 minutes ago, Abstraktum said:

 

Thank you for the pictures and additional information. Would be great if one could compare the diffrent jaw fragments of young T-Rex and Nanotyrannus directly with each other, like you did in this post. :) 

Why it's paramount that all institutions and private collectors work together to a common goal of obtaining accurate answers and not encumbered by who owns it.   With today's technology it's doable. 

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44 minutes ago, Troodon said:

Why it's paramount that all institutions and private collectors work together to a common goal of obtaining accurate answers and not encumbered by who owns it.   With today's technology it's doable. 

So true...

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