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In a previous post, I discussed if Tyrannosaurus rex (Tyrannosaur, Western North America) (Late Cretaceous 68-66 Million Years ago) was able to colonize Eastern North America as the Western Interior Seaway retreat by the early Maastrichtian (I received excellent feedback from other four members, notably @Troodon, that this was prevented by the KT Mass Extinction event 66 Million Years ago). As a result, I don't believe Tyrannosaurus rex was able to effectively colonize Eastern North America (as far as I'm currently aware). However, looking over some records of Late Cretaceous Tyrannosaur fossils, I do believe that a Tyrannosaurid (Yes a Tyrannosaurid) was able to colonize part of Eastern North America in the area of what is today Chronister well, Bollinger County, Missouri! Not much is known about this Tyrannosaur genera, but here is the info I could find on it! Unnamed Tyrannosauroidea genus (Tyrannosaur) (McNair Sand Member of the Ripley Formation-Missouri, US, North America) (Late Cretaceous, 70-66 Million Years ago) (Size unknown) http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&taxon_no=38606&max_interval=Cretaceous&country=United States&state=Missouri&is_real_user=1&basic=yes&type=view&match_subgenera=1 https://www.lakeneosho.org/Ozarks/Chronister2.html https://www.sos.mo.gov/CMSImages/Publications/symbols/dinosauressay.pdf Photographs of the Chonister well Tyrannosaur specimens have also been tricky to find, the only ones I've found were shown during an August 2016 Science in St. Louis Seminar series lecture by Geologist Dr. Micheal Fix, Ph.D., Associate Teaching Professor, Department of Physics of University of Missouri-St.Louis titled Monster in the Hollow: The Story of Missouri's Ozark Dinosaurs. The presentation also showed a photograph of a decent sized Dromeaosaurid tooth from the same site in Missouri!
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Was the Early Cretaceous Theropod Siats an early Non Tyrannosaurid Tyrannosauroid?
Joseph Fossil posted a topic in General Fossil Discussion
I remember very well when I was in Middle school and the discovery of the fossils of the early Cretaceous theropod Siats meekerorum (Cenomanian Creteaceous (What is now western North America), 94 Million Years ago) in Utah was announced in 2013. The incredible discovery was on the front page of a decent amount of the newspapers for sale at my local Jewel grocery store (I even cut out the part of the newspaper describing Siat's discovery and still have it). Image Credit: Jorge Gonzales https://www.sci.news/paleontology/science-siats-meekerorum-dinosaur-utah-01567.html At the time, I simply heard it was a carnosaur (specifically an allosauroid) and didn't really notice debates about Siat's taxonomic placement...That is until two days ago. I was researching Tyrannosauroid diversity in Early Cretaceous North America when I came across a recent Scientific paper from July 2022 by Paleontologists Dr. Darren Naish and Dr. Andrea Cau analyzing Eotyrannus lengi and other Tyrannosaur dinosaurs placement within Tyrannosauroidea. It's pretty well researched and I highly recommend you guys read the paper!!! https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9271276/ Despite the paper being pretty well researched, the authors made a conclusion that has me scratching my head a bit - they place Siats as a Non Tyrannosaurid Tyrannosauroidea!??- 4 replies
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- carnosaurs
- early cretaceous
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Hello, everyone. I have a T-rex tooth. It has a wear surface at the distal serration. Yes, I think it is black, but when I shine it with strong light, it appears brown and slightly yellow. I would like to know what causes the wear surface to show different colors? Thank you
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Recently acquired this beautiful T. rex tooth, just over 5cm / 2” length. Such teeth are typically dark brown / mahogany coloured but this specimen appears to have escaped the usual staining. The location of find (Hell Creek Fmn, nr. Mosby, Garfield Co., Montana, USA), basal rectangular cross section and thicker enamel supports identification that this is a Tyrannosaurus rex maxillary tooth. The fact that the whitish / pale colouration is consistent throughout, absence of pitting / “dried out” appearance / absence of splintering would seem to preclude sun-bleaching.
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Something that has been baffling me for a while is the fate of the European genera of Tyrannosauridae after the Mid Cretaceous. Multiple Tyrannosauridae genera including Proceratosaurus (Tyrannosauridae, England, Great Britain, Middle Jurassic (166 Million Years ago): ironically one of the earliest known Tyrannosauridae from the fossil record currently known), Eotyrannus (Tyrannosauridae, Wessex Formation, Isle of Wight, Early Cretaceous (136.4-125.45 Million Years ago)) and an unnamed Tyrannosauridae genera from Germany (Early Cretaceous (130.0-122.5 Million Years ago)) are known from Mesozoic deposits in Europe dating from the Middle Jurassic up to the Early Cretaceous. Holtz, Thomas (December 1998). "A new phylogeny of the carnivorous dinosaurs". Gaia. 15: 5–61. https://www.geol.umd.edu/~tholtz/gaiaphyl.pdf Hutt, Stephen & Naish, Darren & Martill, David & Barker, Michael & Newbery, Penny. (2001). A preliminary account of a new tyrannosauroid theropod from the Wessex Formation (Early Cretaceous) of southern England. Cretaceous Research. 22. 227-242. 10.1006/cres.2001.0252. https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=242e6d5f962a143900f3c8d2ff5eb20d6fe7482b K.-P. Lanser and U. Heinhofer. (2015). Evidence of theropod dinosaurs from a Lower Cretaceous karst filling in the northern Sauerland (Rhenish Massif, Germany). Palaeontologische Zeitschrift 89:79-94 https://www.semanticscholar.org/paper/Evidence-of-theropod-dinosaurs-from-a-Lower-karst-Lanser-Heimhofer/94860c34dedf8ac6d65759af9725ae76402eef59 But by the Late Cretaceous around 70-66 Million Years ago, they are absent from the fossil record in the region. Instead, the top predators of the region at the time seem to be Abelisaurs and large pterosaurs. Isasmendi, Erik & Torices, Angelica & Canudo, José & Currie, Philip & Pereda Suberbiola, Xabier. (2022). Upper Cretaceous European theropod palaeobiodiversity, palaeobiogeography and the intra‐Maastrichtian faunal turnover: new contributions from the Iberian fossil site of Laño. Papers in Palaeontology. 8. 10.1002/spp2.1419. https://onlinelibrary.wiley.com/doi/full/10.1002/spp2.1419 I’m curious on what could have caused this faunal turnover (especially since that between the Ealy Cretaceous (at the time of the known records of Tyrannosauridae from Europe) and the Late Cretaceous, Europe was basically a series of islands) or if they were still present in Europe during the Late Cretaceous and specimens have yet to be found or properly categorized? What do you guys think?
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- abelisaurs
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Hello! Looking to ID this asian theropod tooth from the late cretaceous of Bayankhongor, Mongolia that is supposedly from Alioramus sp. The serrations are quite worn for this rooted tooth and are hard to see, the entire tooth measures 60mm Below I've attached some pictures, thanks in advance!
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- alioramus
- alioramus remotus
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Could Tyrannosaurus rex have created unique cultures
Joseph Fossil posted a topic in Questions & Answers
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? -
Hi, there. I had a question for how to identify a Tyrannosaurid's tooth which is a T.rex, Aspletosaurus, Gorgosaurus or Albertosaurus. Can we only distinguish the types of tooth fossils by the Formation where the tooth found, such as Hell Creek Formation or Lance (Creek) Formation ? Are there other possible criteria for distinguishing ? For example, the shape of the tooth or the measurement data. I was very confused because when I looked at the maxilla teeth of Tyrannosaurid' they all looked the same(Except for Nanotyrannus). Thanks for your guys answers and help.
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https://www.nationalgeographic.com/science/article/call-to-split-tyrannosaurus-rex-into-3-species-sparks-fierce-debate https://www.nytimes.com/2022/02/28/science/tyrannosaurus-rex-three-species.html?smid=tw-share Gregory S Paul new paper has just dropped with an interesting hypothesis to say the least. I for one think it is worth considereing.
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A tooth of early tyrannosauroidea members from northern China
Agent_Zigzag posted a topic in Member Collections
Greetings! This is my first share on this forum. I was looking through my collections, and one thing popped my mind was this tooth -- a tooth of Xiongguanlong baomoensis,which i found in 2014 but I could not give a very conclusive identification until earlier this year. I was lucky enough to travel along with a group of scientists into the Gobi desert in Northern China. That day we was traveling in the border zone of three different provinces, basically middle of nowhere. This basin is where most dinosaur from Gansu found -- including X. baomoensis, Auroraceratop rugosus, Lanzhousaurus magnidens, etc. I found two dozen of borken teeth on a random hill. In the beginning I thought those teeth could be either iguanadon, hadrosaurus or some crocodilians. After collecting them and bringing them back to Beijing, I went focusing on other real-life project (preparing for college, preparing for grad-school, etc.). It became a memory sealed in attic and lost until I was re-examining the crocodilian fossils I found from the same trip. Then my eyes fell on this tooth, which I recalled seeing similar teeth from the Lanzhou Geological Mesuem and labelled X. baimoensis. After a further comparing with other teeth from the same clade in museums in China, I am certain that this tooth could belongs to X. baomoensis. X. baomoensis is one of the most mysterious member of the superfamily Tyrannosauroidea, and only thing I could be sure that they could grow larger than the specimen preserved in Lanzhou -- for I found a large theropodian matatarsal from the same site and it's certainly larger than the skeleton they demonstrates. I put it somewhere in my mountains of boxes, please allows me some time to look for it.-
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Hi all, Recent find in an old collection. It appears to be a theropod fossil toe bone but I cannot tell what genus or species, or formation. I don’t want to jump to conclusions so I’m putting it out there to all you good people to help hive mind an answer. Thanks!
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A new study has been released, looking into a more accurate estimate of Tyrannosaur walking speeds. New modelling points to much slower speeds than previously thought; now estimated to be approx. 3mph. "Must go faster"......maybe not. Link: Walk the dinosaur: New biomechanical model shows Tyrannosaurus rex in a swinging gait https://phys.org/news/2021-04-dinosaur-biomechanical-tyrannosaurus-rex-gait.html
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Baby tyrannosaurs dinosaurs were the 'size of a Border Collie'
Thomas.Dodson posted a topic in Fossil News
An analysis of a tiny tyrannosaurid jaw bone and claw have been used to extrapolate probable egg and baby size. https://www.sciencedaily.com/releases/2021/01/210125113121.htm https://www.bbc.com/news/uk-scotland-edinburgh-east-fife-55796799 The paywalled article published in the Canadian Journal of Earth Sciences. I'd be interested in the methodology if I can find a free source complete article. https://cdnsciencepub.com/doi/abs/10.1139/cjes-2020-0169-
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Hello everyone, On this edition of Rex or nano, we have this nice little mailbox score I got earlier this year. The seller and I are reasonably certain that it is a young adult rex. But I wanted to bring it to you folks to get your assessment. It matches the locality of Rex ( hell creek, from a microsite in Carter county) and based on my research from the forum and elsewhere it checks out as tyrannosaurid. (Ie: robustness and seemingly no pinch) Bonus question: I'm also curious on the placement of the tooth in the animals jaw. I have reason to believe it may be a right maxillary tooth.
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Hi I decided to make this since the new Tyrannosaur from Alberta’s Foremost Formation, Thanatotheristes deerootorum has just been named and described. Enjoy!! Tyrannosaur bearing Formations in Canada: Formations in Alberta but most of the Formations on my list are I Alberta anyway. Horseshoe Canyon Formation 74-68 million years ago, Alberta: Albertosaurus sarcophagus, possibly Daspletosaurus sp. but no compelling evidence so far. Oldman Formation 78.2-77 million years ago, Alberta: Daspletosaurus torosus, Gorgosaurus sp. Foremost Formation 80.5-78.2 million years ago, Alberta: Thanatotheristes deerootorum, possibly Gorgosaurus sp. Milk River Formation 84.5-83.4 million years ago, Alberta: Tyrannosaur. indet could be a species of Thanatotheristes, possibly Gorgosaurus sp. Scollard Formation 68-66 million years ago, Alberta: T. rex, possibly Nanotyrannus Formations in British Columbia: Wapiti Formation 76.8-70 million years ago, Alberta, British Columbia: Unknown Albertosaurinae either Gorgosaurus or Albertosaurus, possibly Daspletosaurus sp. Tumbler Ridge 135-74 million years ago, British Columbia: Tyrannosaur. indet Formations in Saskatchewan and Manitoba: Dinosaur Park Formation 77-75.5 million years ago, Alberta, Saskatchewan: Daspletosaurus sp., Gorgosaurus libratus Frenchmen Formation, 68-66 million years ago, Saskatchewan: T. rex, possibly Nanotyrannus Bearpaw Formation 75-72 million years ago, Alberta, Saskatchewan, Manitoba: Daspletosaurus sp. one specimen from Daspletosaurus sp. that drowned. For now these are all the Tyrannosaurs known from Canada. No Eastern Tyrannosaurs in Canada yet either but maybe someday. I will also update this and add as more information comes available.
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Quick tour of my trip to The Ultimate Predator: T.rex exhibit at the American Museum of Natural Hisptory, NYC back in September. Some pics are not of the best quality and I apologize - the room was very dark. Speaking of which, in that dark room when you come face to face with Tyrannosaurus rex at the end of the exhibit, you are left imagining how frightening it would be to encounter such an animal in the evening . Most representations of Tyrannosaurus rex I come across don’t phase me because they either appear too outdated, or unrealistic. This is one is different because it’s not Hollywood. Whether the representation is accurate or not, it’s realistic and quite the brute. Would love to know everyone’s thoughts on this giant rex display. Positives: If you love Tyrannosaurus rex / tyrannosaurs then this is for you: all updated information and facts regarding the animal and its lineage. Dinosaur models are all very cool, realistic, and finally with feathers. Some very rare, incredible specimens on display, but few. Organized and easy to follow as you walk through the timeline. Negatives: Much more replicas than actual specimens.
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I have 2 campanian tyrannosaur fossils, one from the Judith river formation from Blaine county in Montana, and another where the only locality I know of is that’s from the two medicine formation. I was wondering if the locality can help determine between Gorgosaurus, Daspletosaurus and Albertosaurus, or if any formations are limited as to which species is present.
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Are juvenile tyrannosaur teeth rare?
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From the album: Dinosaur Fossils collection
Collection of North American Tyrannosaur teeth: T-Rex, Daspletosaurus, Gorgosaurus, Nanotyrannus, Albertosaurus and Aublysodon-
- albertosaurus
- aublysodon
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