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  1. Hello, I am trying to identify if this is a T. rex tooth. It's described as "natural juvenile Tyrannosaurus tooth". Location: Hell Creek Formation, Montana. Dimensions: Height: 4.3 cm Width: 3.8 cm I've read this awesome post by troodon, and I'm leaning towards T. rex ("fat" and rounded tip) - but looking forward to seeing your opinions as well. Thanks and have an awesome day ahead!
  2. Just saw this on a Facebook a preprint just released from a very prestigious dinosaur paleontologist Nicholas Longrich. From the abstract "Here, we review multiple lines of evidence and show that the totality of evidence strongly supports recognition of Nanotyrannus as a distinct species." "placement of Nanotyrannus outside of Tyrannosauridae as a non-tyrannosaurid member of Tyrannosauroidea." https://osf.io/preprints/paleorxiv/nc6tk/?fbclid=IwAR3_YkPSpKBQXk5Aiff0sJRKsl59dIqqO5DXveSjV-tx24Vs6ZLuRZdcaHs
  3. Howdy all. I've discussed the relationships between Nanotyrannus and Appalachiosaurus to albertosaurines and to eachother before, and today I'm wondering if relationships could be determined by the shape of their teeth. Comparing the teeth of nanotyrannus and appalachiosaurus, they are very similar to eachother, almost identical. They are also relatively similar to the teeth of gorgosaurus, though not as much. I believe it's already been established that these animals are relatively closely related, but I think this to be extra evidence to the case. (These fossils are not mine)
  4. Josh_irving

    Identifying Tyrannosaurid Tooth

    Hello Everyone, I bought this tooth nearly ten years ago as a Albertosaurus tooth from the Two Medicine formation, Montana, U.S.A. Whilst updating my labels I have learnt that Albertosaurus is not found in the Two Medicine Formation. As a result, i am asking if anyone can ID this tooth (i know it is very difficult or more likely impossible). I believe it is either a Distal Maxillary or a Distal Dentary tooth. The MC is 18 whilst the DC is 16 which gives it a DSDI of 1.125. The tooth is 2.90cm tall and the base of it is 1.22cm by 0.86cm. the link to some fairly high quality photos is: Tooth Id - Imgur thanks in advance, Josh
  5. Frightmares

    IMG_4351.jpeg

    From the album: Dinosaur Teeth

  6. Frightmares

    IMG_6628.jpeg

    From the album: Dinosaur Teeth

  7. Frightmares

    IMG_6629.jpeg

    From the album: Dinosaur Teeth

  8. Frightmares

    IMG_6630.jpeg

    From the album: Dinosaur Teeth

  9. Hi guys, I made this post about this small theropod tooth from the lance creek formation, Wyoming, USA. I bought it years ago and it was sold to me as belonging to a dromaeosaurid. It doesn't seem to me that it corresponds to any "raptor", but to a baby of Tyrannosaurus rex/Nanotyrannus lacensis. What do you say? Thanks in advance! Ps: the tooth is 1,2 cm/0.47 inch long and 0,6 cm/0.24 inch wide.
  10. Updated Nov 25, 2022 Collectors, online sellers and some dealers periodically ask me to help them in the identification of tyrannosaur type teeth. So I thought I would put together a guide from Western North America (US/Canada) to help in identification. The following is the current understanding of those Tyrannosaurids described/known with the stratigraphic unit where they are found. If I missed any let me know. Albertosaurus sarcophagus : Horseshoe Canyon Formation cf Albertosaurus indet: Wapiti Formation Gorgosaurus libratus : Dinosaur Park Formation Gorgosaurus sp. or cf Gorgosaurus: Two Medicine Formation, Oldman Formation, Foremost Formation, Daspletosaurus horneri : Two Medicine Formation Daspletosaurus wilsoni: Judith River Formation Daspletosaurus torosus : Oldman Formation Daspletosaurus sp. or cf Daspletosaurus: Dinosaur Park Formation Dynamoterror dynastes: Menefee Formation Tyrannosaurus rex : Hell Creek Formation, Lance Formation, Frenchman Formation, Scollard Formation, Denver Formation, (Trex fossils are also known from: Livingstone Fm, Laramie Fm, McRae Fm, Willow Creek Fm) Tyrannosaurus sp.: Javelina Formation, Ojo Formation Nanotyrannus lancensis : Hell Creek Formation, Lance Formation cf Nanotyrannus : Frenchman Formation, Scollard Formation, Denver Formation Thanatotheristes degrootorum : Foremost Formation Tyrannosaurid indet. (spp): Judith River Formation, Mesaverde Formation (Group), Fruitland Formation, Aguja Formation Teratophoneus curriei: Kaiparowits Formation Lythronax argestes: Wahweap Formation Nanuqsaurus hoglundi: Prince Creek Formation Tooth Identification Aublysodon mirandus Premaxillary teeth, those without serrations. This dinosaur is considered nomen dubium and teeth ascribed to it belong to other Tyrannosaurs. Albertosaurus sarcophagus Probably the easiest to identify since its the only Tyrannosaurid described from the Horseshoe Canyon Formation. The most important item in acquiring one of these teeth is the provenance of where it was found. Alberta is not adequate to identify it. You need a specific locality like Drumheller or Tolman Bridge. BTW this is true for all the Tyrannosaurid's discussed in this topic. A disposition is also needed for all dinosaur teeth removed from Alberta. These teeth can get quite large from collection of SMM Gorgosaurus libratus (cf, sp.) The first step in identification is Provenance: you need to know State/Province along with the County (USA) or Locality (Canada) where the tooth was found. Differentiating isolated teeth between Gorgosaurus and Daspletosaurus is very difficult and in most cases its indeterminate. A paper that came out in 2005 which was authored by Phil Currie et al. studied isolated teeth from this period looking at tooth and serration morphology. Their conclusion was that "it is difficult to quantifiably distinguish these teeth reliably by taxon". Therefore identifying them as Tyrannosaurid indet. is the easiest approach in those faunas that Gorgosaurus may be present? There is a quantitative process described in a new paper that may help which will be discussed later. Please note that lots of collectors would like to use size to differentiate these teeth from Daspletosaurus. However Gorgosaurus teeth can get quite large as seen in this photo of a Maxilla with one tooth which is over 3 inches and located in the back of this jaw. Daspletosaurus horneri, D. wilsoni, D. torosus (cf, sp.) The first step in identification is Provenance: you need to know State/Province along with the County (USA) or Locality (Canada) where the tooth was found. A paper that came out in 2005 which was authored by Phil Currie et al. studied isolated teeth from this period looking at tooth and serration morphology. Their conclusion was that "it is difficult to quantifiably distinguish these teeth reliably by taxon". Therefore identifying them as Tyrannosaurid indet. is the easiest approach in those faunas that Daspletosaurus may be present? However, its reasonable to say that teeth over 4" are PROBABLY from a Daspletosaurus. There is a quantitative process described in a new paper that may help which will be discussed later. *****Since the Judith River and Two Medicine Formations fall within the range of all three of these species its going to be difficult to assign teeth to a specific species unless you know the age of the deposit it. Denver Fowler: "Hill County exposures are more easy to date because there we have the boundary between the upper Oldman Fm and the lower part of the Dinosaur Park Fm. Havre exposures were called Judith River Fm historically, but we should probably use Oldman & Dino Park now." And maybe ditto for those teeth found in the Belly River Group of Alberta. Denver Fowler "I expect that D. wilsoni is stratigraphically equivalent to the lower part of the Dinosaur Park Formation. At the moment this is based on the fact that the Judith in eastern Montana was deposited at the time when the WI seaway was receded at its maximum (in the Campanian)" Denver's response to my question on this subject. "There isn't currently any evidence for stratigraphic (time) overlap between the species. However, the 2Med and Judith River likely represent enough time such that it would be possible to find D. torosus in the Judith and both D. torosus and D. wilsoni in the 2Med." (Posted by Denver Fowler) Tyrannosaurus rex/ Nanotyrannus lancensis (cf, sp.) Whether you agree or disagree that Nanotyrannus is a valid taxon what is very clear to me is that we have two distinct morphologies of tyrannosaurid teeth at the very end,of the cretaceous. I can say that because I have handled over 1000 teeth over the years ranging from 3 mm to 5 inches two morphs are present in all ranges up to around 2 inches. Serration density through sampling I've done with teeth in my collection do not appear by itself to be a differentiator between these two morphologies. Density will change with size becoming less on larger teeth and can be the same with equivalent size teeth with both morphologies. DSDI (Denticle Size Difference Index) is also not a differentiator and through my sampling and Carr (2004) and indicates that DSDIs decrease in progressively larger specimens, that is, there are fewer mesial denticles per given unit length than distal denticles in large specimens and there are as many or more mesial than distal denticles in small specimens. Also, the DSDI among dentary teeth is higher than that in the maxilla, indicating that mesial denticles are smaller in the dentary than in the maxillary dentition. So how do you tell the difference between these two morphologies. Well, if a tooth is larger than 2 1/2" and has bulk its clearly T rex, regardless of what the serrations say. It cannot be anything else. With small teeth since serrations density is not a differentiator the other characteristic of the tooth plays a key role. I've found that maxillary teeth can be the most difficult to differentiate and a few teeth are just indeterminate, at least with me. The best way to distinguish between the two morphology the shape at the base, compression of the crown and tip and if there is a pinch at the base. Shape at the base T rex dentary teeth and the very anterior maxillary teeth are oval at the base while Nano teeth are unique as tyrannosaurids and rectangular. However, T rex maxillary teeth can be rectangular so you will have to determine if there is a pinch at the base a characteristic found on Nanotyrannus teeth Here are examples of the cross sections of couple small Rex teeth under 1 1/2 inch and Adult Nano's Tyrannosaurus rex Dentary teeth are oval Maxillary Teeth are rectangular Nanotyrannus Bases are rectangular and show a pinch on both sides. Profile of the teeth is another characteristic Nanotyrannus teeth are compressed, with a pointed tip T rex teeth are fat, with a rounded tip, often the serrations wrap around from the mesial to distal carina to form a continuous carina Crown Height Ratios In the study I did, since nothing is published, with 30 Nanotyrannus teeth the average was 2.2 For Trex teeth the mean for Maxillary teeth is 1.75 and for Dentary its around 2 but all these can change depending on position Heterodonty in Tyrannosaurus rex: implications for the taxonomic and systematic utility of theropod dentitions Joshua B. Smith (2005) T rex Premaxillary Teeth can easily be confused with dentary D1 position. Here is a photo of how to determine what you have. Identifying Gorgosaurus and Daspeletosaurus Teeth using Dental Features A recent paper by Hendrickx et al. (Oct 2019) has provided us a way to try to identify certain teeth using dental features. Positional Daspletosaurus & Gorgosaurus teeth have distinct denticle features that can hopefully can be used to differentiate the species which currently does not exist. Together with @Omnomosaurus we are looking at studying this technique to determine if its a practical method for collectors to use for identification, obtain data on campanian tyrannosaurid teeth and try to understand if the results we are getting is any good? We will be using teeth from my collection and members for the study. @dinosaur man has a topic where a lot of member data will be collected. Step 1 The most critical part in using this process is knowing where the tooth sits in the jaw - Premaxillary, Mesial or Lateral Here is a photo of to help in determining its location Paper https://www.researchgate.net/publication/261630184_Morphometry_of_the_teeth_of_western_North_American_tyrannosaurids_and_its_applicability_to_quantitative_classification Step 2 DSDI (Denticle Size Difference Index) needs to be determined DSDI = MC / DC MC = Number of denticles per 5 mm on the mesial carina at mid-carina DC = Number of denticles per 5 mm on the distal carina at mid-crown Mesial Carina is on the outer curvature Distal Carina is on the inside curvature Step 3 1) If your tooth is from a lateral position in the jaw and your DSDI is <0.8 your tooth may be considered a Gorgosaurus or cf Gorgosaurus depending on the locality of where it was found. 2) If your tooth is from a Mesial position in the jaw and your DSDI is >1.2 your tooth may be considered a Daspletosaurus sp. or cf Daspletosaurus depending on the locality of where it was found. Premaxillary Teeth 1) In my opinion all these teeth should be identified as "Tyrannosaurid indet" 2) The paper does make the following statement "In the young specimens of Daspletosaurus, the carinae of the premaxillary teeth are unserrated (TMP 1994.143.1; Currie, 2003) and show the beaded condition. My concern is that it does not specify what size young teeth are and its looking at TMP 1994.143.1 which is a Daspletosaurus sp in Dinosaur Park Fm. Do all Daspletosaurus premax teeth in other faunas have contain similar features? Gorgosaurus premax teeth are not mentioned. Study Currently 33 teeth from the collection of Troodon, Omnomosaurus, dinosaur man Localities included : Judith River Formation (18 teeth), Two Medicine Formation (13 Teeth), Dinosaur Park Formation (1 Tooth), One unknown Results: 1) None of the lateral teeth have had DSDI < 0.8 and could be described as Gorgosaurus 2) Three of the Mesial teeth had DSDI > 1.2 and could be described as Daspletosaurus 3) One of the Premaxillary teeth was not serrated but could not verify if it was a young tooth 4) So 9% of the population can be tentatively assigned Hendrickx et al paper https://palaeo-electronica.org/content/2019/2806-dental-features-in-theropods
  11. Do you think its possible that nanotyrannus and tyrannosaurus could've shared a similar relationship to lions and hyenas where they would hunt at different hours to avoid competition? (Lions and hyenas hunt the same prey, but lions hunt at night whereas hyenas hunt at day.)
  12. Hi y'all, about a year ago I started digital sculpting on my tablet and began with some Devonian "shark" teeth, inspired by ones in my collection (see topic here). Several months later after becoming more familiar with the process, I decided to try my hand at dinosaur skulls. In particular, I wanted to render the juvenile Tyrannosaurid, "Jane" (BMRP 2002.4.1) since regardless of your stance on the species, it's an important and cool fossil. Here I present my amateur first pass. My end goal is to have a 1:1 scale 3D print. And for you Tyranno-nerds, yes it accurately has incisiform premaxillary teeth with a lingual apicobasal ridge. To get the shape of all the teeth right, I referenced a couple in my collection. They were duplicated and squashed around to match the variation in morphology of the dentition. I also uploaded the model for you to interact with; honest critiques are welcome as it's not a final version I feel is ready for full scale printing. Certain aspects of the anatomy, especially the hard-to-see interior portions are probably where most errors lie. In December, I however did print a smaller scale to see how it looked: The nice thing about digital sculpting is that I can copy the entire skull and very readily reshape it into a similar one. The natural choice is to do a young juvenile / baby T. rex. This is as much a hypothesis as it is art. I based it off of the Witmer Lab's more rigorous reconstruction of "Chomper", and a similarly-sized young Tarbosaurus (which was a close cousin of T. rex). I again uploaded the model for your enjoyment / inspection: Next, I decided to wander much farther from Tyrannosaurs and shape it into a Troodontid, Pectinodon bakkeri. Of course Pectinodon is only known from its teeth, so I at least got the shape of those right (again, based off of a fossil in my collection). The rest was inspired by the reconstructions of others, presumably informed by more completely-known Troodontids. And finally, a sneak peak of what I'll be working on, Acheroraptor temertyorum. This time it's from scratch since there are some things I want to do differently. Thanks for reading, hope you enjoyed!
  13. Hi All, Completely new to the world of fossil collecting and starting small and safe with teeth! But I’m conscious that there are a lot of fakes out there so to be safe I’ve completely written off the popular, colourful Auction site. I have two fossils at the moment (please see my other real/fake post!) which I decided to buy off a website. They are well regarded on local groups and forums so seemed like the proper way of buying my first fossils. In hindsight, I may have naively rushed into the purchases out of excitement without getting opinions from TFF (more because I didn’t know this place existed!). My second fossil was, a small Nanotyrannus tooth. The stated information is given below: Nanotyrannnus lancensis Hell Creek Formation, Maastrican, Powder River County, Montana, USA I do hope they are genuine, but I’d rather know the truth if they aren’t. If it is real, I’d also been keen to know any insight on condition, features, opinions you all may have! Finally, if anyone has any recommended sites/auctioneers etc. to find good quality fossils, feel free to PM me as any help would be greatly appreciated. Thanks in advance!
  14. ThePhysicist

    Juvenile T. rex tooth

    From the album: Hell Creek / Lance Formations

    Interesting blue color near the base, and some feeding wear at the tip of this immature Tyrannosaurid tooth.
  15. 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
  16. ThePhysicist

    Tyrannosaur premaxillary tooth

    From the album: Hell Creek / Lance Formations

    This kind of incisor-like ("incisorform") tooth was originally thought to have belonged to a large, Cretaceous mammal. Later discoveries revealed that these teeth were actually the front teeth ("premaxillary teeth") of Tyrannosaurs - and are now known as a hallmark of their clade, Tyrannosauroidea. Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to scrape meat from bone. Given the size, this is from a very young animal. Should Nanotyrannus be valid, then this should be considered an indeterminate Tyrannosaurid.
  17. ThePhysicist

    Tyrannosaur premaxillary tooth

    From the album: Hell Creek / Lance Formations

    This kind of incisor-like ("incisorform") tooth was originally thought to have belonged to a large, Cretaceous mammal. Later discoveries revealed that these teeth were actually the front teeth ("premaxillary teeth") of Tyrannosaurs - and are now known as a hallmark of their clade, Tyrannosauroidea. Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to scrape meat from bone. Given the size, this is from a juvenile animal (smaller than "Jane"). Should Nanotyrannus be valid, then this should be considered an indeterminate Tyrannosaurid.
  18. AranHao

    nano

    This tooth has always been described as nano . but I found that the both sides of the crown were not pinched, the base of the tooth was obviously pinched on the tongue side, and the other side (lip side) did not seem to be pinched. There is a little root on the tooth bottom (the pinch on both sides of the nano is for the crown?) The mesial ridge extends to 2/3 of the crown the fossil from powder county HCFM CH:5cm CBL:2cm CBW:1.2cm DC:2.5/mm Any insight on this would be greatly appreciated
  19. I'll break my trip report to South Dakota into two parts. First will be my visit to the BHI followed by collecting adventure The purpose of going to the BHI was to pick up the Leptoceratops maxilla's I left during my June trip. Pete has been collecting and pulling together specimens to understand and possibly describe this ceratopsid in the Hell Creek. The material he's collected so far appears to be from an adult and is much smaller than L. gracilis. My maxilla's seem to fit the smaller morphotype. In addition, the BHI provided me two sets of replicas of my specimens, pretty cool. Tankankaceratops is a controversial ceratopsian described by Ott and Larsen 2010. It's a small Triceratopsini known from a partial skull. Pete showed me its occipital condyle which is fused and indicative of an adult. Very cool nasal horn core. Here is a close up of Struthiomimus sedens hand/part of arm... the business end. Good reference photos A new addition to the museum is a cast of a juvenile Tarbosaurus skeleton that was being assembled in June trip Here is some White River material that was recently collected. Think Pete said the top left skull was a rare Camelidae Hespercyon Took photos for reference of the metatarsals from Nanotyrannus Another reference bone a Nanotyrannus carpal bone, much longer than any found on T rex.
  20. 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
  21. Hi Everyone! I'm a little perplexed by this one. The tooth is definitely a Nanotyrannus, that much I'm sure of (Hell Creek, Powder River County, Montana) but it has a strange groove at the base near the mesial side. My best guess is that another tooth dug into it within the jaw or above the gumline. Impacted? Is that the correct dentistry term for that? Also does this count as a pathology or just damage? Anyway, I wanted to see what you all thought if my "impact" hypothesis makes sense or if there's a better explanation. Any insight is greatly appreciated as always!
  22. Nanotyrannus35

    Possible Dakotaraptor Tooth

    I have this tooth that I got from Tooth Draw Quarry. It's probably nano, but just wanted to make sure. CH is 15mm CBL is 8 mm. Serration density is about 4/mm distal and maybe 5 mesial. Sorry for the blurriness. Also, the base is only pinched on one side. Thanks for any help.
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