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Saskatchewan researchers have reportedly discovered an extensive network of blood vessels preserved in the fossil of a tyrannosaur rib. This discovery, if confirmed, would be the first of its kind. Sask. research teams make rare find inside Scotty T. rex fossil How dinosaur blood vessels are preserved through the ages Scientific Reports Who is Mauricio Barbi

Some news from Germany regarding the Tyrannosaurus rex "Tristan Otto" Poor Tristan Otto had a nasty bone disease. It was found by using a CT-based, nondestructive imaging approach. Full article: CLICK

Hello! I inherited this piece with the idea that it could possibly be a space rock. I checked the magnetism and it has no magnetic properties whatsoever. After closer examination with an open mind and a little imagination, I see a petrified baby dinosaur laid on its side with its neck possibly broken at the base of the skull. Below what looks like the neck is a split section that looks like a chest cavity with a arm/leg on either side. . The strangest part is that there seems to be the head of another species resting on the side of the laid down fossil. I see the right eye socket at the top of the head and the raised ridges on top of the skull back to the decapitation point. (It almost looks like it could be a tiny horse laid on its side, but it looks like little fingers on the end of what looks like the front leg)

My first post on the forum was to see if anybody could show me an adult specimen of “Nanotyrannus.” I was more forceful in that approach because, from what I’ve seen on Twitter, “Nano” fans like to argue with paleontologists on the validity of the genus, even though these scientists have been studying dinosaurs for years and have degrees and Ph.Ds in different scientific fields. The evidence points them in a different conclusion compared to the public, and the fact that they are being so heavily resisted against with regards to this topic is baffling. I decided to play the “Nano” fans at their own game, and wrote a question in a cocky manner to see if anybody could give me something of value regarding an adult “Nanotyrannus” specimen. I expected a hostile reaction akin to what you find on Twitter, but the feedback was mostly positive. I was told a couple of things regarding how I worded my post, which was to be expected, among other things, but there was a comment that sent me to a post written by a person with the username "Troodon." Titled "The Case for Nanotyrannus," which I think was inspired by Larson's paper of the same name, goes over some traits that seem to be unique to "Nanotyrannus." With all due respect to Troodon, the points that they made have been debunked by multiple paleontologists who have studied "Nanotyrannus" fossils for years. Troodon also wrote a comment in response to my question, and they fell for my cocky persona and decided not to respond to the critiques that I had regarding not having an adult “Nano.” So now, I will try a different approach. I am going to list the biggest reasons why “Nano” does not exist, and see where this gets me next. These critiques, I believe, truly hinder any conclusive argument to support “Nano’s” identity, and some of these arguments come from other professional paleontologist who argue against “Nano’s” validity. Therefore, I am curious to see what the responses would be this time. My points: 1. No adult “Nano” specimen, only juveniles. It's truly baffling to me that only juvenile Nano species have been found, and yet it's okay to make it a separate genus. Yes, there are other dinosaurs known by juvenile, or subadult, specimens, but they are considered valid genera because of the circumstances thats surround them. Let's use Alioramus. Alioramus is known from two, maybe three if you count Qiazhousaurus, specimens that are not fully grown. So naturally, Alioramus could be a juvenile of another larger tyrannosauroid that coexisted with Alioramus and Qiazhousaurus: Tarbosaurus. However, we DO have a growth series for Tarbosaurus, with very young and mature individuals. Therefore, Alioramus (and/or Qiazhousaurus) is a valid genus. Same goes for Bagaraatan. The same cannot be said for "Nanotyrannus." We only have juvenile specimens of "Nano." Maybe this wouldn't be so bad if it coexist with T. rex, but here's the problem: we do not have a growth series for T. rex. I'll talk more about this later. Woodward et al., (2020), and Carr (1999), have proven that "Nanotyrannus" has no fully-grown individuals, contra Bakker et al., (1988) and Larson (2013). Since we do not have any fully grown "Nano" specimens, and we only have fully grown T. rex specimens, then the most logical conclusion is that "Nano" is a juvenile T. rex. If an adult Nano is ever discovered, then the case would be closed. However, that never seems to be the case when a supposed "Nano" skeleton is discovered. 2. All juvenile T. rex specimens are labeled as “Nano.” How the heck can a small tyrannosauroid that coexisted with a larger tyrannosauroid be considered a valid genus when we have no juvenile specimens of the latter? When no conclusive juvie rex has been named, and all young tyrannosaurids that coexisted with T. rex are named “Nano,” then the most logical conclusion to go with is that all “Nano” specimens are juvenile T. rex specimens. 3. “Baby Bob”. And this is where I'm sure people will tell me about "Baby Bob." There are two problems with "Baby Bob": it's fragmentary, and it's in private hands. A privately owned specimen cannot be studied by multiple scientists who can verify its authenticity. It needs to be in a museum so that other scientists can have access to it. Second, the specimen is fragmentary. The right side of the dentary may be almost complete, but it's in private hands so we cannot tell. However, based on comparisons with other "Nano"/juvie rex specimens, you can bet that "Baby Bob" had a higher tooth counts than the adults. Or, individual variation explains why "Baby Bob" had a smaller tooth count than a typical juvenile rex. Aside from the dentary, the rest of "Baby Bob" only consists of a pubis, a femur, and a tibia. The rest of the skeleton seems to be missing. However, this cannot be verified because "Baby Bob" is a private specimen. If it wasn't, we would know how complete the specimen is. Therefore, using "Baby Bob" to validate "Nano" is detrimental. 4. No complete adult T. rex hands. Another point that is usually brought up is "Bloody Mary's" ("Dueling Dinosaurs" juvenile T. rex specimen) large hands. However, we do not have a single complete T. rex hand. "Wyrex's" hands are incomplete, and "Sue's" hands were not found with the rest of the skeleton. A manual ungual (hand claw) was found AFTER the skeleton was already dug up (Brochu, 2003, p. 103) (Dr. Thomas Holtz on Twitter). It's inconclusive if this is a T. rex hand claw, or something else. Therefore, "Bloody Mary's" hand is the first complete T. rex hand to be discovered, and it's not an autopomorphic trait of "Nanotyrannus." But wait, what about UCRC-PV 1's arm? Pic from Larson's Instagram. UCRC's hand is smaller than "Bloody Mary's," which would make it a younger individual than "Bloody Mary." Unfortunately, UCRC has not been described in a paper, nor has an histological analysis been done on the skeleton, so it being a "subadult" is a subjective claim. Therefore, using UCRC to prove "Nano's" validity is worthless until a scientist(s) studies the skeleton, and gives a description of the specimen in a peer-reviewed paper. Dr. Holtz provided a drawing of the complete arm bones of "Wyrex" on Twitter. The hand is INCOMPLETE: Pic link here. Therefore, "Bloody Mary's" hand is evidence for what a complete T. rex hand would have looked like towards the animal's mature age. "Wyrex's" COMPLETE hand would have looked identical if the hand was complete. UCRC's hand would have grown to look like "Bloody Mary's" if it matured to the same age. It's also worth noting that all other ”complete” T. rex hands have been copied from Albertosaurus or Daspletosaurus. “Sue’s” hand is incomplete, but it was reconstructed using Albertosaurus' hand (Brochu, 2003, p. 100), and so is “Wyrex’s” (Larson and Carpenter, 2008, p. 46). 5. Carr (2020). Dr. Carr's 2020 paper is one of the best papers on T. rex that I have seen. It describes the physical changes that T. rex went through during ontogeny. CMNH 7541, the "Nano" holotype, "Jane," and "Petey," all fell within the T. rex growth chart, which makes ALL "Nano" specimens juvenile T. rex specimens. This paper even made the CMNH museum recatalogue CMNH 7541 as a juvenile T. rex. The case is closed now. There is officially NO HOLOTYPE SPECIMEN for "Nano." "Nanotyrannus" is a dead genus name. If you want to prove that "Nanotyrannus" is a valid genus, then you'd have to disprove Carr's 2020 paper, and that is near impossible now. Multiple paleontologists who study tyrannosauroids have backed up Carr's paper, so the authority figures have spoken. The burden of proof now lies on the "Nano" fans. You need an adult "Nanotyrannus" specimen. 6. “Nano” is not an albertosaurine. Larson tries to lump “Nano” into the albertosaurine (Larson, 2013). However, all albertosaurine died out before “Nano” evolved (73-68 Ma) (Eberth, 2020). Yun (2015) stated that all apparent albertosaurine traits that "Nano" has are seen in other juvenile tyrannosaurs. This renders this hypothesis mute. All of "Nano's" traits can be explained away due to ontogeny. 7. T. rex lost teeth as it matured. Why is it so hard to imagine T. rex losing teeth as it matured? People compare T. rex to Tarbosaurus when it comes to tooth count, and they use Tsuihiji et al., (2011) for this, but T. rex is more derived than Tarbosaurus, and more derived dinosaurs experienced greater morphological changes as they matured. Other examples are Pachycephalosaurus and Triceratops, two other dinosaurs that coexisted with T. rex. It seems that the dinosaurs of North America 66 Ma experienced amazing transformations when they grew up. Check out Horner's 2011 Ted Talk on the matter. I don't agree with everything that guy says and does, but I have to admit that he's right about "Nano" being a juvenile T. rex. Besides, "Nano" only has two more teeth than the adult T. rex specimen “Samson.” What's the problem with losing two teeth as T. rex matured? And yes, I do know about BHI 6439. What’s to have stopped BHI 6439 from losing teeth as it matured? We also don’t know the age of that animal. I've seen pics of this dentary being compared with "Jane." However, it could be older than “Jane.” Tooth loss could have occurred for that specimen, which is why it has fewer teeth than "Jane" does. Second, BHI 6439 is a private specimen so it doesn’t count. It can’t be verified by other scientists for scrutiny. Carr (1999), (2005), and (2020) has proven that T. rex lost teeth during its growth, so this is an established fact now. Dr. Holtz, and Brusatte, support Carr on this as well. 8. “Nanotyrannus’” brain. The skull of CMNH 7541 was damaged (Carr’s blog, Summary, number 2), which seems have given the appearance of it having a different shape than T. rex’s. Somehow, if the brain case wasn’t damaged, then the brain would have changed shaped as “Nano” matured into a grown T. rex (Kawabe et al., 2015). 9. Pneumatopore on quadrujugal is present in Daspletosaurus horneri. Larson (2013) said that this is an automorphic trait, but once again, Carr proved this to be wrong. Carr et al., (2017) found a pneumatopore on Daspletosaurus horneri's quadrujugal. This is not a trait unique to "Nanotyrannus." 10. “Jane’s” teeth fit perfectly with a juvenile T. rex’s bite marks on a vertebra. It has been said that "Nano's" teeth are too thin to belong to T. rex, but Peterson (2019) showed that "Jane's" teeth matched perfectly with the tooth marks of a juvenile T. rex's. It seems that "Nano's" teeth are stronger than what people claim, and this supports "Nano" as a juvenile T. rex. 11. It’s been hinted that “Nano” was a juvenile T. rex before Carr (1999). Carpenter (1992) hinted that "Nanotyrannus" was a juvenile T. rex before Carr did in 1999. Carr (1999) only helped to solidify Nano as a juvenile T. rex, and his 2020 paper helped to end the debate. Conclusion: When the majority of scientists state that something does not exist, then that is the best conclusion supported by the evidence. These experts set the standards as to how to conduct science properly. If we do not listen to them, then science, like paleontology, ha no standards and anybody can do as they please. That leads to chaos, which is what this whole “Nano” situation is. Nobody is listening to the experts online, but the scientists are doing a great job so far in spreading the truth based on the latest research. CMNH 7541 has been relabeled as a juvenile T. rex in the CMNH museum, so we are on the right track to correcting the mistakes of the past. There are only THREE ways that could bring “Nano” back: 1. An ADULT “Nano” specimen. No teeth, no claws, no bits and pieces of bone. We need an adult specimen that is NOT IN PRIVATE HANDS BUT IN A MUSEUM, has an EFS that shows it has stopped growing and has reached adulthood, and is heavily studied by scientific experts (mainly by the “Nano” deniers, like Carr, Holtz, Brusatte, etc.). Then, it needs to be published in a scientific paper than is peer-reviewed, and open to the public to be verified, or denied, by other scientists. “Nano” will never be verified using privately-owned specimens, or fragments of bones and teeth. 2. We need complete juvenile T. rex specimens that are not in private hands, and show traits that are not seen in “Nano.” This would be near impossible because all “Nano” specimens show T. rex traits. 3. We need a complete adult T. rex hand that shows differences from "BHI 6437 ("Bloody Mary"), which is what we do not have. Not even “Sue,” or “Wyrex,” have a complete hand. This is why “Nano” does not exist. On the bright side, we finally have a growth series of T. rex that shows how this awesome animal transformed as it grew. We should be happy that we have any juvenile T. rex specimens at all. Second, I do understand what the “Nano” fans are going through. My favorite sauropod used to be “Seismosaurus.” Later on, I learned that multiple scientists have proven that it is actually Diplodocus. I was in denial for a while, but I came to the conclusion that I was wrong. Now, my favorite sauropod is Diplodocus. That’s how science works. There are plenty of other small-medium-sized tyrannosauroids that the “Nano” fans could gravitate towards to: Alioramus, Qiazhousaurus (or Alioramus sinensis, depending on who you talk to), Nanuqsaurus, Albertosaurus, Gorgosaurus, Bagaraatan, Raptorrex, or any of the other earlier tyrannosauroids (Guanlong, etc.). All of these dinosaurs have been backed up by scientists for decades as being valid genera. Alioramus is a valid genus because we have a growth serious of Tarbosaurus that shows that Alioramus’ traits are distinctive from Tarbosaurus’. This has been stated mainly by Steven Brusatte, an expert on tyrannosauroids. He also states that “Nano” does not exist, and since he is an expert, his research bears more weight on “Nano” being an invalid taxon (Brusatte et al., 2016). On the other hand, I highly doubt that anyone can argue against Carr’s 2020 paper. With so much detail in it, it would be near impossible to prove Carr wrong on “Nanotyrannus’” invalidity. Unless there is a secret adult fossil of “Nanotyrannus” hidden somewhere, and it is in the process of being placed in a museum, then the most scientifically based conclusion is that “Nanotyrannus” does not exist. The ONLY tyrannosauroid present in North America 68-66 Ma is Tyrannosaurus rex. With regards to the scientists, or scientific advocates, that support “Nano” as valid, I have no ill will against them. For example, Peter Larson. I really do like the guy. He’s passionate about dinosaurs, and helped to discover numerous T. rex fossils. Dr. Bakker is a revolutionary in paleontology, no questions asked. Philip Manning is also very passionate about dinosaurs, and helped to describe the T. rex specimen “Trix.” “Dinosaur” George is another one. I loved his QnA videos back in the day. Unfortunately, with the evidence I’ve laid out above, they’re wrong about “Nanotyrannus” being valid. Links: Carr (2020): https://peerj.com/articles/9192/ Woodward et al., (2020): https://advances.sciencemag.org/content/6/1/eaax6250.full Brusatte et al., (2016): https://www.pure.ed.ac.uk/ws/files/23714255/23714179._AAM._BrusatteetalNanotyrannusResponseMSRevision.pdf Carr (1999): https://core.ac.uk/download/pdf/227005733.pdf Horner (2011): Carr and Williamson (2004): https://www.academia.edu/2291683/Diversity_of_late_Maastrichtian_Tyrannosauridae_Dinosauria_Theropoda_from_western_North_America Carr (2005): https://gsa.confex.com/gsa/2009NC/webprogram/Paper156740.html Larson (2013): https://www.researchgate.net/publication/289687970_The_case_for_Nanotyrannus “The Case for Nanotyrannus” by Troodon: Yun (2015): https://peerj.com/preprints/852/ Bakker et al., (1988): https://zenodo.org/record/1037529#.X9Ai5CVOmEf Carpenter (1992): https://www.researchgate.net/publication/314988830_Tyrannosaurids_Dinosauria_of_Asia_and_North_America Eberth (2020): https://cdnsciencepub.com/doi/abs/10.1139/cjes-2019-0019 Carr’s blog (Summary, number 2). http://tyrannosauroideacentral.blogspot.com/2013/09/nanotyrannus-isnt-real-really.html?m=1 Larson and Carpenter (2008) (P. 46): https://www.google.com/books/edition/Tyrannosaurus_Rex_the_Tyrant_King/5WH9RnfKco4C?hl=en&gbpv=1&bsq=Wyrex Kawabe et al., (2015): https://journals.plos.org/plosone/article/comments?id=10.1371/journal.pone.0129939 Tsuihiji et al., (2011): https://www.researchgate.net/publication/232865497_Cranial_Osteology_of_a_Juvenile_Specimen_of_Tarbosaurus_bataar_Theropoda_Tyrannosauridae_from_the_Nemegt_Formation_Upper_Cretaceous_of_Bugin_Tsav_Mongolia

Hi all. I'd like to begin by thanking the members of this forum for the profound wealth of knowledge that you all have shared with me during my search for further understanding of dinosaurs, fossil collecting, and fossils in general. Prior to joining, I was a longtime lurker that regularly referenced this forum and its many posts to answer countless questions that I had, and I continue to reference it! The information contained on this site is invaluable. I would especially like to thank @Troodon for his amazing guides and detailed write-ups, such as the case made for Nanotyrannus. That really settled the debate for me and convinced me that Nanotyrannus is indeed a separate genus. So thank you all! Now, with that out of the way, I'll get to the point of this post. I recently got my feet wet in this hobby and did what I'm sure MANY beginners have done before me. I began by acquiring a fossil of the most well-known dinosaur, and my personal favorite, Tyrannosaurus Rex. Specifically what was advertised as a partial T-Rex tooth. I can't afford a complete tooth at the moment, so I settled for the next best thing. Based on everything I've learned so far regarding T-Rex teeth and how to ID them, its characteristics seem to lean towards being a Rex tooth, but I'm by no means an expert on the subject, so I'd like to call on the many members of this forum that have more experience than I do and ask if they would be so kind as to share their opinions based on the photos and information provided. So as for the tooth's information. It's a partial tooth that measures 1.38 inches long, and the seller stated that it was discovered in the Hell Creek Formation of Powder River County, Montana. It does seem quite robust, and its shape and relative size seem consistent with Rex teeth. It also has a pretty round cross section. The serrations also seem to be pretty in line with Rex teeth, but I don't know if they provide any clear differential to typical Nano serrations. Photos taken by both the seller and myself have been attached. Thanks in advance for any help/opinions provided!

This was posted on FB by AAPS. It was written by the paleontologist Tom Carr who is an extremist on these matters and as expected its receiving quite a negative reaction on social media. George Winters indicated he is preparing an article to address an opposing view I don't have the paper for now just screen shots so if anyone can add anything please do.

Hi y'all, got this small theropod in the mail; I bought it suspecting it was Tyrannosaurid. Upon in-hand inspection, I believe that suspicion is confirmed. It bears close resemblance to one of my larger juvenile T. rex maxillary teeth. It also appears to have a slight pathology near the apex - a slight bend. @Troodon Tyrannosauridae Hell Creek Fm., Wibaux Co., MT, USA CH: 9 mm Mesial serration density: ~ 5.3 / mm Distal serration density: ~ 5 / mm Serration densities: Serrations: Here the pathology is more evident: Base (comparison with other T. rex maxillary tooth, right):