Search the Community

Hello, I was doing a study on the T. rex and Nanotyrannus teeth specimens I had, and I wanted to compare them against a list of known T. rex teeth with measurement. The paper: Dental Morphology and Variation in Theropod Dinosaurs: Implications for the Taxonomic Identification of Isolated Teeth (JOSHUA B. SMITH, DAVID R. VANN, AND PETER DODSON) contains a list of 115 T. rex teeth. To make it easier to compare and read the data, I combined the measurements into a single chart, added colors and lines for ease of reading, and added the size and names of the T. rex used in the study Feel free to refer to the below chart for T. rex teeth measurements. I had to split the chart into 2 due to size limitations, but if you want the full-sized PDF version (25 MB), please message me so I can send it to you by email. If you have any suggestions to improve readability, or have your own data to add, go ahead and post it here! I will be posting pics and measurements of my various T. rex and Nanotyrannus teeth here @Troodon

I recently found an extremely interesting paper published in the Journal of Comparative Neurology a few days ago by Professor Suzana Herculano-Houzel of Vanderbilt University about the neuron activity within the brain of the Dinosaur Tyrannosaurus rex (Western North America, Maastrichtian Cretaceous 68.0-66.0 million years ago). The study states there is evidence (based on the size of of the Cerebrum section of its brain and the hypothetical amount of neurons (of which for the study M=Millions of Neurons) present in the brain based on its size) Tyrannosaurus rex had between 2,207-3,289M telencephalic neurons in the Cerebrum section of its brain and was capable of problem solving and even forming unique cultures. Herculano‐Houzel, S. (2023). Theropod dinosaurs had primate‐like numbers of telencephalic neurons. Journal of Comparative Neurology. https://doi.org/10.1002/cne.25453 https://onlinelibrary.wiley.com/doi/epdf/10.1002/cne.25453 Usually I'm a bit skeptical when claims like this are made, but for Tyrannosaurus rex, I'm not surprised the least bit. It's been known for quite a while the brain to body ratio of Tyrannosaurus rex is larger than that of most other dinosaurs at 1.0 kilogram in weight (with only the Raptor dinosaur Troodon likely having a larger brain to body ratio among non-avian Theropod dinosaurs). Brain Image Credit: Ashley Morhardt https://www.earthtouchnews.com/discoveries/fossils/theres-a-lot-to-learn-about-dinosaur-brains/ Larsson, H.C.E. (2001). Endocranial anatomy of Carcharodontosaurus saharicus (Theropoda: Allosauroidea) and its implications for theropod brain evolution. In: Mesozoic vertebrate life, eds Tanke D.H; Carpenter K; Skrepnick M.W. Indiana University Press, 19–33 https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.20983 The recent study A large portion of its brain was devoted to smell, but I can easily see how the size of its brain could accommodate enough neuron activity for problem solving skills and even forming cultures. What do you guys think? What do you think of the study and what would Tyrannosaurus cultures have looked like?

A while back, I was researching the number of likely Tyrannosauroidea dinosaurs that inhabited the Southern Hemisphere (I know this is a very controversial subject) in the Early Cretaceous for an extra credit research paper I was doing for my freshmen year college geology class. As I was looking for data for the paper, I found an unusual data entry on the paleontological database website fossilworks.org - It lists Tyrannosauridae remains from Jurassic Madagascar. http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&collection_no=55391 The specimen MSNM V5819 (consisting of a partial tooth) was apparently found in Mahajanga, Madagascar at the Bathonian aged Isalo Illb Formation (dating 167.7-164.7 million years ago) in 2003. S. Maganuco, A. Cau, and G. Pasini (2005) First description of theropod remains from the Middle Jurassic (Bathonian) of Madagascar. Atti della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, 146(2):165-202 https://www.researchgate.net/publication/257651210_First_description_of_theropod_remains_from_the_Middle_Jurassic_Bathonian_of_Madagascar (You can read the actual paper with this above link). Here is also two photographs from the paper of the specimen MSNM V5819 The authors of the paper (which I must say did a really good job with the research and paper itself) state that a healthy degree of caution must be given in assigning MSNM V5819 to Tyrannosauroidea. Still, if this is indeed correct, It would be one of the earliest members of Tyrannosauroidea, with the only currently known older Tyrannosauroidea taxon being Proceratosaurus of England. The Specimen MSNM V5819 is maybe even older than Kileskus of Russia, Guanlong of China, and Aviatyrannus of Portugal. Still, the only currently known specimen is a single tooth, MSNM V5819, and I'm not 100% certain this represents a member of Tyrannosauroidea? What do you guys think?

I've heard very recently about the upcoming sale of the Tyrannosaurus Rex Skull Maximus and I'm horrified another priceless dinosaur specimen is once again out of the hands of science and into the hands of the ultra rich. This Smithsonian article is a great summary of what's happening, though it incorrectly states the specimen's age at 76 Million years old (T-Rex lived between 68-66 Million Years ago). https://www.smithsonianmag.com/smart-news/a-t-rex-skull-named-maximus-could-fetch-15-to-20-million-at-auction-180981116/ Though the fossil trade occurs around the world, this problem seems to be most concentrated in the United States as of recent. I think it's about time that the U.S revisit its national laws and pass reform to the trade of large fossil vertebrates. For one thing, there could be a requirement that the only ones allowed to participate in auctions like the Maximus one should be Reputable Museums since this is dealing with the Earth's collective heritage and (so Museum's aren't bankrupt by paying gigantic amounts of money to buy fossils from Private landowners), the State where a large vertebrate fossil was found in should cover the full payment within a reasonable period (maybe a month to 12 months) to the landowner and give the fossil to the Museum so everyone can have a chance to study the fossilized specimens. This is just me spitballing some ideas, but what do you think? Do you think fossil auction and trade reform legislation is necessary in the United States and if so, what suggestions/reforms would you like to see implemented?

Greetings, is there anyone that could recommend a fossil expert located in Southern California that could come on site to certify a series of dinosaur fossils that have been uncovered. Specifically, petrified/opalized dinosaur fossils. Thanks in advance!

There's a new documentary about dinosaurs (Prehistoric Planet). In this documentary we see a lot of dinosaurs and their appearance is quite different from movies (JW series) one of the most interesting is the Tyrannosaurus rex. This is because The T.rex had lips instead of showing cusps of their maxilla teeth. Actually, I really like the new look. It looks more like an animal than a monster from movies, but i'm very curious why did T.rex have lips? what is their evidence? I'm more interested in the basis for their idea. Does anyone know which paper has mentioned or discussed and studied this problem? "Did Tyrannosaurus Rex really have lips?" Thank guys very much for your reply and sharing. have a lovely day~

Hi, Dear guys. I had a question about T.rex teeth I'm very confused by this question and hope to get an answer. we knew a T.rex‘s dentary tooth that will have a pinch in one side with the tongue. how about a maxilla tooth that will also have a pinch on one side? I guess that answer is not. And about another question: There is a tooth available online. Is it a dentary/maxilla tooth? and why. Please. From Weston County, Wyoming, United States 7¼ inches (18.5 cm) in length. Thanks guys for the help. Have a nice day. from Chris

Hey all Here in Auckland, we have a special visitor to our museum - Peter the Tyrannosaurus rex. As you'd probably guess, this is not a common sight for New Zealand so I had to check it out! I visited the (very modest) permanent display upstairs too and took some pics for you all to see The pic quality isn't the best, I didn't take my DSLR with me so it was all taken using my aging phone. There isn't much more to say, I'll let the pics do the talking.....

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, saw this listing for a tooth, it’s from Meade County, South Dakota and looks to me like either a Nanotyrannus or Tyrannosaurus rex tooth. Want your opinions, I personally am leaning towards Nanotyrannus due to the pinch however it seems to be pretty robust. Thanks in advance measures about 1 cm

I was in the area, so I made a very brief stop by the HMNS. I'll state up-front that this will be extremely dino-centric. What I saw was really great, they have a chronologically-organized display of animals from stromatolites to humans (I only made it to the Cretaceous). The lighting is very dramatic, so seeing it in person is much better than the dark photos portray (I did edit a few of them to enhance visibility). Lots of dynamic posing which is nice compared to other museums. Also, most specimens aren't behind glass, and you can get really close. I believe most of the skeletons are casts (except for a couple of exceptional ones), but they're done well and don't disappoint. They currently have Victoria the T. rex as a traveling exhibit, although I think it has been recently moved and reduced in size to make room for the new traveling exhibit. She's one of the most complete individuals of T. rex and only slightly smaller than Sue (12' tall, 40' long, ~10.5 tons). Victoria was found in SD in 2013. She died sometime in her 20's (?), possibly from an infected bite on her lower jaw from another T. rex. Various elements: I think the feet aren't original. Coracoids, furcula, gastralia: Caudal vertebrae: Cervical vertebrae, some are fused: They had one of her femurs and her skull displayed separately:

Found in hell creek fm

Here's a (hopefully) interesting question on a topic well outside my wheelhouse. In the break room at the Florida Museum of Natural History sitting on top of the double refrigerators is a cast of a coelacanth, a painted resin cast of a Tyrannosaurus rex foot (the left one), and inexplicably a cleaning sponge that one of the artists at the museum has modeled into a cartoon character named Robert with quadrilateral trousers. I've been looking at these objects while nuking my lunch in the microwave oven next to the refrigerators for several months now. Just yesterday I finally noticed that there was something odd (to me) about the T-rex toes. Leading up to the ultimate distal/ungual on each of the three toes (disregarding the hallux "dew claw") are a varying number of phalanges. Somehow I had naively assumed that the number of phalanges in each toe would for some reason be consistent. For reference, each of the digits in our human hands have two phalanges (proximal and intermediate) leading up to the distal phalanx (ungual) on all but our highly useful opposable thumbs. Our thumb (pollux in medical speak) makes up for the missing intermediate phalanx by having a metacarpal that has more mobility than the metacarpals of our other digits. I found it fascinating to learn that the 3 primary toes of a theropod dinosaur, labeled II, III, & IV, have (very conveniently) 2, 3 & 4 phalanges leading up to the distal phalanx. I came across this excellent artwork from a paleoartist online: https://emilywilloughby.com/art/gallery/diagrams/theropod-foot-comparison It seems that our modern day dinosaurs (birds) share this same asymmetry in toe bones as the T-rex that started this little investigation. I'm guessing that to those who have taken anatomy or physiology classes or have a deeper understanding of birds or dinosaurs this would be common knowledge but somehow I've never paid enough attention to theropod feet till now. I do so enjoy learning new tidbits of information (quite regularly from this forum). In the off chance that this might be enlightening to other members I thought I'd share my micro-epiphany instigated by some T-rex toes on top of a fridge. Cheers. -Ken

Just curious, because seller listed as nano

I’m thinking about buying one of them, assuming their the same price which one is better? my general overview- tooth in matrix is smaller, only .75 inch. But higher quality. However It can’t be id, it can be either Nanotyrannus or trex the other tooth is significantly bigger but has more wear and is confirmed to be trex. There’s no picture of bottom but I asked for one and ofc if they send it and it’s not a trex tooth I’m not going to buy it.

Hi all Emmm, this is my first Tyrannosaurus tooth, yes, I had no experience at the time, but I still remember how excited I was when I got this tyrannosaurus tooth, even now. Yes, he was a broken tooth, and it was expensive.And now I want to know the tooth ID.I think it's nanotyrannus. All I know is it's from hell Creek, Montana, no county. Thanks