Search the Community
Showing results for tags 'tyrannosaurid'.
-
How to differentiate megalosaurid and tyrannosaurid tooth
ruminate posted a topic in Questions & Answers
Hello everyone! Just a question, whats the best way to diffrentiate the tooth morphology between megalosaurids and tyrannosaurids? -
I was very pleasantly surprised (actually more thrilled to be honest) when I heard about the discovery of the northern tyrannosaurid dinosaur Nanuqusaurus hoglundi from the Cretaceous Prince Creek Formation dating 70.6-69.1 Million Years ago in what is now the U.S. State of Alaska. Image Credit and Source: https://www.researchgate.net/publication/260757717_A_Diminutive_New_Tyrannosaur_from_the_Top_of_the_World At first thought to be only 5-6 meters (16-20 feet) in length based on the currently catalogued specimens, it's now believed based on currently undescribed remains to be 8-9 meters (26-30 feet) in length fully grown (compared to the 12.3-12.4 meters (40.4-40.7 feet) in length it's cousin Tyrannosaurus rex could reach fully grown). Image Credit: Artist Nathan Rogers Image Source: https://www.artstation.com/artwork/Z5w900 Fiorillo, A. R., & Tykoski, R. S., 2014. A diminutive new tyrannosaur from the top of the world. PloS one, 9(3), e91287. https://doi.org/10.1371/journal.pone.0091287 Druckenmiller, P. S., Erickson, G. M., Brinkman, D., Brown, C. M., & Eberle, J. J. (2021). Nesting at extreme polar latitudes by non-avian dinosaurs. Current biology : CB, 31(16), 3469–3478.e5. https://doi.org/10.1016/j.cub.2021.05.041 https://www.cell.com/current-biology/fulltext/S0960-9822(21)00739-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982221007399%3Fshowall%3Dtrue The Tyrannosaurid Nanuqusaurus is also unique as the northern most tyrannosaur known from Western North America (at the time the continent of Laramidia). Adapted to the colder climates of the region, it shared its habitat with a vast diversity of plants, small mammals, and other non-avian dinosaurs including hadrosaurs such as Edmontosaurus, the pachycephalosaur Alaskacephale, the Ceratopsian Pachyrhinosaurus, and a large currently unnamed genus of troodontidae. But it's confirmed geologic range is only during the early Maastrichtian (70.6-69.1 Million Years ago) of the Cretaceous period. Images Credits and Sources: https://www.researchgate.net/publication/260757717_A_Diminutive_New_Tyrannosaur_from_the_Top_of_the_World Fiorillo, A. R., and Gangloff, R. A., 2001. Theropod teeth from the Prince Creek Formation (Cretaceous) of northern Alaska, with speculations on Arctic dinosaur paleoecology. Journal of Vertebrate Paleontology. 20(4):675-682 Image Credit: Artist Nathan Rogers Image Source: https://www.artstation.com/artwork/Z5w900 The question I have is why this is? Did anything major happen to the habitat of the Prince Creek Formation between the Early-Late Maastrichtian? Did Nanuqusaurus live up to 66 Million Years ago to the latest Maastrichtian of the Cretaceous period?
- 5 replies
-
- 1
-
-
- alaska
- cretaceous
- (and 12 more)
-
Questions about the Giant Tyrannosaurid species Tyrannosaurus mcraeensis and Cretaceous Tyrannosaurid diversity
Joseph Fossil posted a topic in Questions & Answers
Perhaps one of the most exciting scientific papers in a while about the genetic diversity of the Tyrannosaurid genus Tyrannosarus itself (the genus that includes the famous and well documented T-rex) was just announced and published (or at least the abstract of it)!!! Image Credit: Dalman et al. 2023 (abstract) and the Society for Vertebrate Paleontology (SVP). https://vertpaleo.org/wp-content/uploads/2023/10/2023_SVP_Program-Final-10032023.pdf At the Society for Vertebrate Paleontology's annual meeting for 2023, Paleontologists Dr. Sebastian Dalman, Dr. Philip J. Currie, and seven other experienced Paleontologists and experts on the Tyrannosaurid theropod dinosaurs published an abstract on October 21, 2023 about a new species of Tyrannosaurus (Tyrannosaurus mcraensis) from the Hall Lake Formation dating 72 Million Years ago to the Campanian-Maastrichtian Cretaceous of what is now New Mexico!!! This not only gives insights on the origins of the genus Tyrannosaurus, but validates previous hypothesis over the years (at least since 2013) that a unique giant Tyrannosaur from southern Larmidia (now Western North America) that lived during the Campanian-Maastrichtian Cretaceous!!! Names given to this animal over the years include Alamotyrannus brinkmani and Tyrannosaurus brinkmani. A Digital Reconstruction of the Tyrannosaurus species Tyrannosaurus mcraensis and it's size compared to an average Human, April 2022. Image Credit: Artist LancianIdolatry https://twitter.com/LancianIdolatry/status/1511016414252978182 This is especially true given for how long the debate has been raging on the Validity ofThe species Tyrannosaurus mcraensis was when fully grown the same size of the averaged size adults of the later Tyrannosaurus rex from the later Maastrichtian Cretaceous. By the look of things with the Paper and the experienced paleontologists and Tyrannosaur experts who authored it, it seems just by looking at its abstract it will be be far more through and accurate than the recent Gregory S. Paul Paper from 2022 and maybe even prove the validity of the debate Tyrannosaur species Tyrannosaurus vannus from the 70-66 Million Years ago dated Javelina Formation of what is now Texas. But I'm wondering if anyone has more information on this study and the potential of it's results?
- 9 replies
-
- 2
-
-
- alamotyrannus
- alamotyrannus brinkmani
- (and 22 more)
-
Shown below are 3 different types of dinosaur eggshell, all said to be from the Gaugou Formation in China. The bottom left eggshell is labelled as coming from Dendroolithus, and I am confident in this identification. The other two types are supposed to come from Tarbosaurus bataar (top left) and Oviraptor philoceratops (right) however, and neither of these species are known from the Gaugou Formation, so the question is what they are actually from. Thanks in advance for any suggestions Othniel
-
Hi all, Do you agree that this 0,7 inch tooth from the Hell Creek formation is a tyrannosaurid premax, or could it be something else? Thanks!
-
Gorgosaurus sp. (libratus?) partial femur (Lambe, 1914) Tyrannosaurid theropod Family: Tyrannosauridae Subfamily: Albertosaurinae Genus: Gorgosaurus (Lambe, 1914) Labelled as being a partial femur (thigh, upper leg). Late Cretaceous (Campanian), 75.1 – 76.6 Ma Red Deer River Valley, Nr. Drumheller, Alberta, Canada. Unboxing my old collection that has been in storage for years and forgot that I had this (purchased August 1988) – labelled as being a Gorgosaurus sp.partial femur. I am assuming that the groove was for a tendon or blood vessel? It appears that fossilised / mineralised spongiform material is visible in the cross-section at one end – might this be fossilised / mineralised bone marrow or spongy (cancellous) bone? Areas of mineralised bone surface also appears to be present. Research suggests that it is likely from the Dinosaur Park Formation which is especially prolific in dinosaur remains and well exposed in the badlands which flank the Red Deer River.
- 20 replies
-
- 1
-
-
- canada
- canada fossils
- (and 9 more)
-
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!
- 5 replies
-
- 9
-
-
- art
- baby t rex
- (and 14 more)
-
I recently read that the only skeleton currently known of Appalachiosaurus was of a juvenile, and the adult animal was significantly bigger. The juvenile skeleton was about 21 feet long, and the animal likely weighed 1,300 pounds. This skeleton is about the size of a juvenile Tyrannosaurus rex (using the "Jane" specimen for scale, BMRP 2002.4.1) and, this raises a question in my mind. Is it possible that Appalachiosaurus montgomeriensis would have attained adult sizes close to what we see in adult specimens of Tyrannosaurus rex? And as such, could we classify it as a megatheropod? Of course there are several other factors in this, such as age, growth stages, and environmental pressure that the animal may have experienced in life.
-
Hello everyone, first post from me here. I have a 1.8 cm (roughly 0.71" for those who don't use the metric system) Hell Creek tyrannosaurid tooth that is in need of identification. Currently, the tooth is labeled as N. lancensis, though a while ago, the seller labeled the tooth as a juvie T. rex, and now I'm confused about whether I should label it as a Nano, a Rex or a Tyrannosauridae indet. (though since it's from HC it should be either of the first two) Notes: - Total serration count: 55 on both sides. - Pic 1, which consists of shots of the same tooth taken from all angles, was sent to me by the seller (the sketch in red was also his), which shows how the tooth is laterally compressed - quite interesting and not very T. rex-like, considering that even juvenile T. rex teeth are quite bulky. Moreover, the mesial carinae also ends quite high. Because of this, I had some doubts about his ID and would like a second opinion. TIA!
.thumb.jpg.81b585b901ca37228a28d9b7e88aa30b.jpg)
.jpg.beaca234bbff3f61817983650be96dff.jpg)
-
The North American Tyrannosauroidea Species from the Aptian-Santonian Cretaceous
Joseph Fossil posted a topic in General Fossil Discussion
The Tyrannosaur Dinosaurs (Tyrannosauroidea) inhabited North America from 152 Million Years ago during the Late Jurassic era up until 66 Million Years ago during the Late Cretaceous era. https://www.app.pan.pl/article/item/app20110141.html However, there is a relatively large geologic gap between the time of the Late Jurassic to the Santonian-Campanian stages of the Cretaceous (when the the oldest known Tyrannosaurid Lythronax (Late Creteaceous, 81.9-81.5 Million Years ago) emerged) in terms of the number of Tyrannosauroidae confirmed in North America. However, this doesn't mean they were completely absent from the Continent. Rather, they remained small to mid sized predators under the shadow of Large Carnosaurs up until the Cenomanian-Turnonian extinction event 93-94 Million years ago, which the tyrannosaurs filled the role of Apex Predator in most terrestrial ecosystems by the Campanian stage of the Cretaceous. The Tyrannosaur geologic gap between the Late Jurassic and Santonian Cretaceous is also not completely empty and several confirmed Tyrannosauroidea are known from this time period in North America. I've created a list of known Tyrannosauroidea species and specimens from the Aptian-Santonian Cretaceous of North America which I would like to share on the fourtm (let me know if there are any examples I'm missing or should add): Unnamed Cloverly Formation Tyrannosauroid (Tyrannosaur – Cloverly Formation, Wyoming, US, North America) (Early Cretaceous, 108 Million Years ago) (Based on Specimen FMNH PR 2750, likely grew up to 1.2 meters (3.9 feet) in length) https://www.tandfonline.com/doi/abs/10.1080/08912963.2010.543952 https://www.researchgate.net/profile/Lindsay- Zanno/publication/229287579_On_the_earliest_record_of_Cretaceous_tyrannosauroids_in_western_North_America_Implications_for_an_Early_Cretaceous_Laurasian_interchange_event/links/0fcfd50089dd8f3955000000/On-the-earliest-record-of-Cretaceous-tyrannosauroids-in-western-North-America-Implications-for-an-Early-Cretaceous-Laurasian-interchange-event.pdf Unnamed Wayan Formation Tyrannosauroid (Tyrannosaur – Wayan Formation, Idaho, US, North America) (Early Late Cretaceous, 100.6-97.8 Million Years ago) (Based on Specimen IMNH 2251/53975, grew up to 1.2 meters (3.9 feet) in length) https://bioone.org/journals/journal-of-paleontology/volume-96/issue-6/jpa.2022.42/A-partial-tyrannosauroid-femur-from-the-mid-Cretaceous-Wayan-Formation/10.1017/jpa.2022.42.full Unnamed Lewisville Formation Tyrannosauroid (Tyrannosaur - Woodbine Group Lewisville Formation, Texas US, North America) (Late Cretaceous (100-95 Million Years ago)) (Based on Specimens DMNH 2013-0701701 and SMU 77218, grew up to 2.7-4.8 meters (8.8-15 feet) in length) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8796713/ Moros intrepidus (Tyrannosaur – Cedar Mountain Formation, Utah, US, North America) (Early Cretaceous (96.4 Million Years ago)) (Grew up to 1.2 meters (3.9 feet) in length) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6385174/ Suskityrannus hazelae (Tyrannosaur – Moreno Hill Formation, New Mexico, US, North America) (Early Cretaceous, 93.5-89.3 Million Years ago) (grew up to 3 meters (9.8 feet) in length) https://www.pure.ed.ac.uk/ws/files/82474043/82473554._Brusatte._AAM.pdf -
Can someone ID this tooth ? Is it worth buying?
-
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.
- 24 replies
-
- 1
-
-
- hell creek fm.
- montana
- (and 6 more)
-
The two most prominent hypothesizes on the direct evolutionary origin of perhaps the most famous Theropod Dinosaur from the fossil record, Tyrannosaurus Rex (Tyrannosauridae, Late Cretaceous (68-66 Million Years ago)) are what I call the Laramidia and Asian Origins. The Laramidia origin (named after the region of the Western North America which was a separate Continent during most of the Late Cretaceous and home to a vast amount of dinosaurs including Tyrannosaurus rex) hypothesizes that Tyrannosaurus rex is the direct descendent of and evolved from slightly older North American Tyrannosaurids like Daspletosaurus (Tyrannosauridae, Late Cretaceous (79.5-74 Million Years ago)). Warshaw, Elías & Fowler, Denver. (2022). A transitional species of Daspletosaurus Russell, 1970 from the Judith River Formation of eastern Montana. PeerJ. 10. e14461. 10.7717/peerj.14461. https://www.researchgate.net/publication/365746599_A_transitional_species_of_Daspletosaurus_Russell_1970_from_the_Judith_River_Formation_of_eastern_Montana The Asian origin hypothesizes that Tyrannosaurus’s direct ancestor was a Tyrannosaurid from Asia. This supported by how closely related the Asian Tyrannosaurid Tarbosaurus (Tyrannosauridae, Late Cretaceous (70 Million Years ago)). This hypothesis further elaborates that a that the Asian Tyrannosaurids arrived in Western North America via a land bridge between what is now Eastern Russia and Alaska around 73-72 Million Years ago. On arrival, theses Asian Tyrannosaurids outcompeted and caused the extinction of most of the Native Tyrannosaur species of Laramidia (including Albertosaurus (Tyrannosaurid, Late Cretaceous (71-68 Million Years ago)), creating conditions allowing for the emergence of the genus Tyrannosaurus. Brusatte, Stephen & Carr, Thomas. (2016). The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports. 6. 20252. 10.1038/srep20252. https://www.nature.com/articles/srep20252 Takasaki R, Fiorillo AR, Tykoski RS, Kobayashi Y (2020) Re-examination of the cranial osteology of the Arctic Alaskan hadrosaurine with implications for its taxonomic status. PLoS ONE 15(5): e0232410. https://doi.org/10.1371/journal.pone.0232410 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0232410 Both hypotheses have points that are supported by the fossil record, but still don’t fill all the gaps in answering the question of the direct origin of the genus Tyrannosaurus. There is however another hypothesis I have pondered over for at least the past few months which could fill in some (if not all) the gaps to this question. It is the Hybrid Speciation Origin hypothesis. The Hybrid Speciation Origin hypothesis basically states that after a land bridge formed between Eurasia and Laramidia during the Late Campanian stage of the Cretaceous (73-72 Million Years ago) and the Asian Tyrannosaurids arrived in Laramidia, certain individuals of a Asian Tyrannosaurid genus breed with a species of a genus of Native Laramidia Tyrannosaurid (likely a direct descendent of Daspletosaurus). Enough of these inter-genus breeding events occurred that a new Tyrannosaurid genus distinct from its parent species (and genuses) emerged around 68 Million Years ago, Tyrannosaurus. I will admit this would be extremely difficult to prove, but I do believe it could be a valid hypothesis. It corroborates the many similarities in skeletal structure Tyrannosaurus shares (and how closely related it is phylogenetically) with the Asian Tyrannosaurid Tarbosaurus and the skeletal structure similarities and general body shape it shares with Daspletosaurus. Image Credit: https://www.nature.com/articles/srep20252 Brusatte, Stephen & Carr, Thomas. (2016). The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports. 6. 20252. 10.1038/srep20252. https://www.nature.com/articles/srep20252 Warshaw, Elías & Fowler, Denver. (2022). A transitional species of Daspletosaurus Russell, 1970 from the Judith River Formation of eastern Montana. PeerJ. 10. e14461. 10.7717/peerj.14461. https://www.researchgate.net/publication/365746599_A_transitional_species_of_Daspletosaurus_Russell_1970_from_the_Judith_River_Formation_of_eastern_Montana Stein, Walter W.; Triebold, Michael (2013). "Preliminary Analysis of a Sub-adult Tyrannosaurid Skeleton from the Judith River Formation of Petroleum County, Montana". In J. Michael Parrish; Ralph E. Molnar; Philip J. Currie; Eva B. Koppelhus (eds.). Tyrannosaurid Paleobiology. Bloomington: Indiana University Press. pp. 55–77. Currie, P.J. (2003). Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica 48 (2): pp. 191–226. https://www.app.pan.pl/archive/published/app48/app48-191.pdf I am interested in how the tyrannosaurid species Nanuqusaurus (Tyrannosaurid, Late Cretaceous (70-68 (likely also to 66) Million years ago), the Daspletosaur Tyrannosaurid specimen RMDRC 2002.MT-001 “Sir William”, and the Tyrannosaurid specimen CM 9401 could factor into the validity of the hybrid speciation hypothesis. I hold no illusions in thinking this hypothesis is not going to be controversial. But I do think it could be semi plausible. What do you guys think?
-
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.-
- 1
-
-
- dinosaur
- hell creek
- (and 9 more)
-
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?
-
"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
-
- 1
-
-
- hell creek
- hell creek formation
- (and 6 more)
-
"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
-
Any further information on this Tarbosaurus skull?
ChrisMouM posted a topic in General Fossil Discussion
Does anyone know the catalog no. of this skull? And is there any paper mentions this skull? or more descriptions for it. thx guys help. have a lovely day.
-
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.-
- 1
-
-
- aublysodon
- aublysodon mirandus
- (and 15 more)
-
Hi, guys. Does anyone have some high-quality images of Albertosaurus sarcophagus skulls (or maxilla /dentary)? please. and the following images were my sharing, which I found on the internet. Thanks for your guys' sharing. have a lovely day guys.
-
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~
- 2 replies
-
- 1
-
-
- tyrannosaurid
- tyrannosaurus
- (and 1 more)
-
From the album: Dinosaurs
These strange, incisor-like teeth were originally thought to have belonged to a large Cretaceous mammal. Later discoveries showed that these teeth matched the front teeth of young Tyrannosaurs quite well. Given closely spaced, parallel feeding traces on bones, these "incisorform" teeth likely were used to scrape meat from bone. -
I have an interesting question when I read a paper (Hurum, Jørn H.; & Sabath, Karol. Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared) I only found that it was mentioned in the content, T.rex had stereoscopic vision(Stereopsis), but I did not find any description of the vision of Tarbosaurus. Does anyone know that Tarbosaurus had stereovision? If Yes or No, please explain the reasons and provide a paper to prove it.Please Thanks guys. have a lovely day
-
These teeth were sold as a baby tyrannosaurid and a dromaeosaurid/bird respectively. Some other specimens from this lot have been posted here if I recall. But they are from North of Havre, Montana close to the Canadian border. Apparently they are from quite an old collection from around 1950-70s. The provenance should place it solidly in Judith River Formation. Since these teeth were selling somewhat quickly, I just grabbed them and decided on figuring it out later. The first tyrannosaurid tooth does have some similarities to Dromaeosaurus with the mesial twist, but I could be wrong. The second tooth is a bit more confusing. I'm guessing it is Zapsalis-type with those striations which would make it Saurornitholestes. I don't think it's bird compared to bird teeth from other deposits. It's probably not one of those Campanian microraptorians either, and it's probably too big even at this size to be bird or micro. 1st tooth: Length=6.3mm; Distal Density=17.5/3mm; CBL=2.9mm; CBW=1.8mm 2nd tooth: Length=5.8mm; Distal Density= ±11-12/mm (?); CBL=2.6mm; CBW=1.3mm Serration density for the 2nd tooth might not be too accurate since it was extremely difficult to even get to that number. Not sure how to go about getting CH, but it's probably a little bit more than the length since the tips are worn. 1st tooth might be good as is since with that small root section, that probably makes up for what would be a longer crown. 1st Tooth 2nd tooth
.jpg.21e0152b5a563515cee304ee4d100134.jpg)
.jpg.beaca234bbff3f61817983650be96dff.jpg)
