Troodon Posted March 12, 2019 Share Posted March 12, 2019 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. 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. 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 Compare the widths for both of these species, there is no comparison its pretty obvious how robust one is over the other. 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) 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 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" Compare the long bone of Nanotyrannus with arrow to the one below on T rex Sue Sue - Carpal is much shorter and with a different morohology... 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. 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 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. Sub Adult Trex claw Digit II, 5 cm .. compares quite well to adult Victoria not Nanotyrannus 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?" 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 Lawrence M. Witmer Ryan C. Ridgely First published: 26 August 2009 https://doi.org/10.1002/ar.20983 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... 46 Link to comment Share on other sites More sharing options...
ynot Posted March 12, 2019 Share Posted March 12, 2019 Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted March 12, 2019 Share Posted March 12, 2019 Thank you. Very interesting. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
ziggycardon Posted March 12, 2019 Share Posted March 12, 2019 Thank you for posting this! Very informative piece on a very interesting topic Interested in all things paleontology, geology, zoology, evolution, natural history and science! Professional exotic pet keeper, huge fantasy geek, explorer of the microfossil realm, member of the BVP (Belgian Association for Paleontology), Volunteer prepper at Oertijdmuseum Boxtel. View my collection topic here: The Growing Collection of Ziggycardon My animal collection at the "Members pet" topic Ziggycardon's exploration of the microfossil realm Trips to Eben Emael (Maastrichtian of Belgium) My latest fossil hunt Next project will be a dedicated prepping space. "A mind needs books as a sword needs a whetstone, if it is to keep its edge." - Tyrion Lannister Link to comment Share on other sites More sharing options...
fossilsonwheels Posted March 12, 2019 Share Posted March 12, 2019 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. Link to comment Share on other sites More sharing options...
JohnBrewer Posted March 12, 2019 Share Posted March 12, 2019 Great post, thanks Frank. John Map of UK fossil sites Link to comment Share on other sites More sharing options...
Bobby Rico Posted March 12, 2019 Share Posted March 12, 2019 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. Link to comment Share on other sites More sharing options...
Haravex Posted March 12, 2019 Share Posted March 12, 2019 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. Link to comment Share on other sites More sharing options...
LordTrilobite Posted March 12, 2019 Share Posted March 12, 2019 Good stuff. Olof Moleman AKA Lord Trilobite Link to comment Share on other sites More sharing options...
Dracorex_hogwartsia Posted March 12, 2019 Share Posted March 12, 2019 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? 1 Link to comment Share on other sites More sharing options...
Troodon Posted March 13, 2019 Author Share Posted March 13, 2019 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 1 Link to comment Share on other sites More sharing options...
Praefectus Posted March 13, 2019 Share Posted March 13, 2019 Wow. Great post. 1 Link to comment Share on other sites More sharing options...
Masp Posted March 13, 2019 Share Posted March 13, 2019 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. Link to comment Share on other sites More sharing options...
Abstraktum Posted March 13, 2019 Share Posted March 13, 2019 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...): 6 1 Link to comment Share on other sites More sharing options...
Dracorex_hogwartsia Posted March 13, 2019 Share Posted March 13, 2019 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. Link to comment Share on other sites More sharing options...
David in Japan Posted March 14, 2019 Share Posted March 14, 2019 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...): 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. 1 ~~~~~~~~~~~~〇~~~~~~~~~~~~~ Warmest greetings from Kumamoto、 Japan Link to comment Share on other sites More sharing options...
JohnBrian Posted March 14, 2019 Share Posted March 14, 2019 Great post Troodon! ---------------------------------------------------------------------------- John I had a friend once, but the wheels fell off. Sad, very sad. - Nightwing Link to comment Share on other sites More sharing options...
DPS Ammonite Posted March 14, 2019 Share Posted March 14, 2019 Thanks Frank for all your informative posts. You get the E. F. Hutton Award: when you talk everyone listens. 1 My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
Abstraktum Posted March 14, 2019 Share Posted March 14, 2019 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. 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? 1 Link to comment Share on other sites More sharing options...
-Andy- Posted March 14, 2019 Share Posted March 14, 2019 Wonderful post Troodon. Thank you for compiling this info. Looking forward to meeting my fellow Singaporean collectors! Do PM me if you are a Singaporean, or an overseas fossil-collector coming here for a holiday! Link to comment Share on other sites More sharing options...
Troodon Posted March 14, 2019 Author Share Posted March 14, 2019 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. @David in Japan 5 1 Link to comment Share on other sites More sharing options...
Troodon Posted March 14, 2019 Author Share Posted March 14, 2019 @-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. 2 Link to comment Share on other sites More sharing options...
Abstraktum Posted March 14, 2019 Share Posted March 14, 2019 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. Link to comment Share on other sites More sharing options...
Troodon Posted March 14, 2019 Author Share Posted March 14, 2019 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. 2 Link to comment Share on other sites More sharing options...
TyBoy Posted March 14, 2019 Share Posted March 14, 2019 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... Link to comment Share on other sites More sharing options...
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