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Showing results for tags 'tyrannosaurus rex'.
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"That some of these teeth are mammalian incisors there can be but little doubt..." - O. C. Marsh1 This kind of incisor-like ("incisiform") 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 (along with fused nasals). Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to selectively scrape meat from bone2. Identification Tyrannosaurid premaxillary teeth have a "D"-shaped cross section, with the lingual face flattened, and often have an apicobasal ridge on the midline of the lingual face. In more technical language, "...premaxillary teeth bear lingually rotated mesial and distal carinae forming a salinon cross-section at mid-crown height, and a highly convex labial aspect as in tyrannosauroids generally. In mesial/distal views carinae are sinuous, transitioning from lingually convex near the base to lingually concave approaching the occlusal surface. Carinae terminate prior to reaching the root/crown juncture. Mesial and distal aspects of the crown are depressed, yielding a weakly hourglass-shaped cross-section at the crown base... The carinae lack serrations [likely ontogenetically variable]... As in other tyrannosauroids, teeth exhibit a pronounced lingual ridge"3. Most of the current literature supports only one Tyrannosaurid species in the Hell Creek formation, Tyrannosaurus rex, a hypothesis subject to change in light of new evidence. Comments This tooth has no discernible antemortem wear. The collector appears to have applied some preservative coating, giving the enamel a slightly sharper gloss. Given the size, this is from a very young animal (smaller than "Jane", BMRP 2002.4.1). References 1. Marsh, O.C., 1892, "Notes on Mesozoic vertebrate fossils", American Journal of Science, 44: 170-176 2. David W.E. Hone and Mahito Watabe, "New information on scavenging and selective feeding behaviour of tyrannosaurs", Acta Palaeontologica Polonica 55 (4), 2010: 627-634 doi: http://dx.doi.org/10.4202/app.2009.0133 3. Zanno, L., Tucker, R.T., Canoville, A. et al. Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record. Commun Biol 2, 64 (2019). https://doi.org/10.1038/s42003-019-0308-7
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"That some of these teeth are mammalian incisors there can be but little doubt..." - O. C. Marsh1 This kind of incisor-like ("incisiform") 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 (along with fused nasals). Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to selectively scrape meat from bone2. Identification Tyrannosaurid premaxillary teeth have a "D"-shaped cross section, with the lingual face flattened, and often have an apicobasal ridge on the midline of the lingual face. In more technical language, "...premaxillary teeth bear lingually rotated mesial and distal carinae forming a salinon cross-section at mid-crown height, and a highly convex labial aspect as in tyrannosauroids generally. In mesial/distal views carinae are sinuous, transitioning from lingually convex near the base to lingually concave approaching the occlusal surface. Carinae terminate prior to reaching the root/crown juncture. Mesial and distal aspects of the crown are depressed, yielding a weakly hourglass-shaped cross-section at the crown base... The carinae lack serrations [likely ontogenetically variable]... As in other tyrannosauroids, teeth exhibit a pronounced lingual ridge"3. Most of the current literature supports only one Tyrannosaurid species in the Hell Creek formation, Tyrannosaurus rex, a hypothesis subject to change in light of new evidence. Comments This tooth exhibits some antemortem wear at the apex (pictured), on the carinae, and near the base of the lingual apicobasal ridge. Given the size, this is from a juvenile animal (smaller than "Jane", BMRP 2002.4.1). References 1. Marsh, O.C., 1892, "Notes on Mesozoic vertebrate fossils", American Journal of Science, 44: 170-176 2. David W.E. Hone and Mahito Watabe, "New information on scavenging and selective feeding behaviour of tyrannosaurs", Acta Palaeontologica Polonica 55 (4), 2010: 627-634 doi: http://dx.doi.org/10.4202/app.2009.0133 3. Zanno, L., Tucker, R.T., Canoville, A. et al. Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record. Commun Biol 2, 64 (2019). https://doi.org/10.1038/s42003-019-0308-7
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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!
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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. -
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.-
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Idea for legislation to reform the trade in Fossils of Large Vertebrates in the United States
Joseph Fossil posted a topic in Questions & Answers
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? -
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~
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Number of Tyrannosauridae genera in Western and Eastern North America during the Maastrichtian Cretaceous
Joseph Fossil posted a topic in General Fossil Discussion
Along with an interest in Pennsylvanian fish diversity, I've also had an interest (like many others studying Paleontology) in the diversity of Dinosaur genera during the Cretaceous era (particularly the Theropod diversity in North America during the Maastrichtian period 72.1-66 Million years ago). Compared to the preceding Campanian period (83.6-72.1 Million years ago), I've noticed there is a slightly less number of known Tyannosauridae genera in Western North America (at the time a separate continent known as Laramidia). I've come up with a list of confirmed known and possible Tyrannosauridae genera during the Maastrichtian period in Western North America and Eastern North America. Eastern North America (at the time a separate continent known as Appalachia) Dryptosaurus Donoho Creek Formation Tyrannosauridae genera (possibly Appalachiosaurus) https://palaeo-electronica.org/content/2018/2123-appalachia-biogeography Chronister well (Ripley Formation) Tyrannosauridae genera 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 Western North America (Laramidia) Tyrannosaurus Rex Nanuqsaurus (Prince Creek Formation) Albertosaurus (more early Maastrichtian to around 68 Million Years ago) ?"Alamotyrannus" (could also be a species of Tyrannosaurus - ?Tyrannosaurus brinkmani) ?"Daspletosaurus sp. (Horseshoe Canyon Formation) (specimen CMN 11315) (more early Maastrichtian to around 68 Million Years ago) https://cdnsciencepub.com/doi/10.1139/cjes-2014-0072 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079176/ I'm wondering if this is an accurate list, why is there a dip in Tyrannosauridae diversity in Eastern and Western North America after the Campanian (was it a result of the Deccan Volcanic eruptions in India around the same time, at least for Western North America (if this theory is current) the Native Western North American Tyrannosaur genera being outcompeted by the Eurasian ancestors of Tyrannosaurus Rex arriving in North America via a land bridge during the late Campanian Early Maastrichtian, or both), the status on the taxonomic validity of Alamotyrannus, was Nanuqusaurus present during the later part of the Maastrichtian, and did Albertosaurus and Tyrannosaurus Rex ever come into direct contact with one another? -
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
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From the album: Hell Creek / Lance Formations
The preservation of theropod teeth doesn't get much better than this. -
From the album: Hell Creek / Lance Formations
It's remarkable that the minute features of this tooth can be preserved with such clarity after 66 million years! -
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
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From the album: Hell Creek / Lance Formations
As a theropod tooth aficionado, I thought it useful to compare two families present in the Hell Creek Formation. They become increasingly difficult to distinguish as they get smaller, but this graphic presents some features which may be used to differentiate them on two similarly-sized exceptional specimens. Keep in mind there is some variability due to position, ontogeny, etc., so it's beneficial to study more than one tooth for each family.-
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From the album: Hell Creek / Lance Formations
Not the prettiest tooth, but I very much enjoy fossils like this that demonstrate behavior and tell a story. T. rex and other Tyrannosaurs were unusual among theropods in that they consumed the entire carcass of an animal - bones and all. Most theropod dinosaurs have ziphodont teeth, thin and knife-like, good for cutting muscle from bone. The thick and robust teeth of adult Tyrannosaurs, coupled with their incredible bite force, allowed them to shatter and pulverize bone - even those of the large, formidable herbivores they hunted. Despite the robustness of their teeth, Tyrannosaurs often broke them in the process of biting. It may have been a while before the broken tooth was replaced by a new one, so in the meantime, the broken tooth would continue to accumulate wear. This is one such tooth, a large portion of the tooth was broken off when the animal bit into another dinosaur, and it was still used afterwards for some time before it was replaced. Based on the placement and extension of the carinae to the base of the tooth, and the size, this was an anterior tooth (at the front of the mouth, probably the first dentary tooth) of an adult individual. See Schubert & Ungar (2005) for a discussion on Tyrannosaur tooth wear features (open-access). -
From the album: Hell Creek / Lance Formations
Not the prettiest tooth, but I very much enjoy fossils like this that demonstrate behavior and tell a story. T. rex and other Tyrannosaurs were unusual among theropods in that they consumed the entire carcass of an animal - bones and all. Most theropod dinosaurs have ziphodont teeth, thin and knife-like, good for cutting muscle from bone. The thick and robust teeth of adult Tyrannosaurs, coupled with their incredible bite force, allowed them to shatter and pulverize bone - even those of the large, formidable herbivores they hunted. Despite the robustness of their teeth, Tyrannosaurs often broke them in the process of biting. It may have been a while before the broken tooth was replaced by a new one, so in the meantime, the broken tooth would continue to accumulate wear. This is one such tooth, a large portion of the tooth was broken off when the animal bit into another dinosaur, and it was still used afterwards for some time before it was replaced. Based on the placement and extension of the carinae to the base of the tooth, and the size, this was an anterior tooth (at the front of the mouth, probably the first dentary tooth) of an adult individual. See Schubert & Ungar (2005) for a discussion on Tyrannosaur tooth wear features (open-access). -
Found in hell creek fm
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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
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Just curious, because seller listed as nano
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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.
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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
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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.....
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From the album: Hell Creek / Lance Formations
It's interesting to compare differently-sized teeth of similar positions. These might represent ontogeny or other dental variation (due to multiple species, etc.).-
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From the album: Hell Creek / Lance Formations
It's interesting to compare differently-sized teeth of similar positions. These might represent ontogeny or other dental variation (due to multiple species, etc.). -
From the album: Hell Creek / Lance Formations
Sold by the BHI as Nanotyrannus lancensis. However, given the uncertain status of Nanotyrannus' validity, I chose to label it as Tyrannosaurid for now. It is interesting to compare to my other small Tyrannosaur teeth of the same/similar position. The base is clearly more compressed than my baby rex tooth (which is also smaller). -
From the album: Hell Creek / Lance Formations
A Tyrannosaur tooth from Eastern Montana. Given the basal "pinching," this would be Nanotyrannus lancensis if it's valid (otherwise it's T. rex). Interesting to compare it to my other small Tyrannosaur teeth. The tip was probably broken after fossilization, but the gouges on the labial face may be inflicted while the tooth was in use. Note that the enamel is well-preserved with sharply resolved texture and is still clear.
