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  1. Jeffrey P

    Western Adventure Part 6

    One week fossil collecting trip out west, my sixth time in the past six years. Flew into Denver. Rented a car and headed down to Castle Rock where I spent the night at a motel. Next day drove up to Florissant Fossil Quarry. It was Wednesday and they're normally closed during the week in September, but I made special arrangements for a few hours visit. Compared to my two previous visits there, didn't do as well. The other times, I was there for the whole day, this time was just for three hours, and they had had a considerable amount of rain recently and so the shale was more crumbly and more difficult to split. Here are some of my finds. Plants:
  2. Jurassicbro238

    Lance shark tooth ID help

    A friend of mine found this tooth in Niobrara county, Wyoming while sifting at a microsite. I was thinking Chiloscyllium but I'm not 100% sure and I don't know much about shark tooth ID. Does anyone know what it is? The pinhead is 1.2 mm long for scale.
  3. Ericlin

    Ceratopsian frill or horn

    Hello, I have this fossil, and I was wondering whether it is a ceratopsian frill or horn, it looks like a frill but seems to be circular. It’s from the Lance formation and measures about 2 inch in length. As always thanks!
  4. 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
  5. Ericlin

    Lance formation fossils

    Hello, I brought some lance formation channel deposit matrix and was wondering if anyone could help id some of the weirder fossils. Thanks. 1. Some sort of scale? Maybe garfish? 2.skull piece? Not sure 3.not sure 4.not sure 5. Turtle shell? 6.not sure 7.skull piece? 8.gastralia? 9.not sure 10.not sure 11. Theropod toe bone? 12. Could it be identified as a theropod claw frag? 12.not sure Appreciate any help, and thanks
  6. Edited (04/14/23) With all of the new discoveries over the past few years there is very little out there that is current or accurate. Here is my view of the Dinosaurian/Crocodilian fauna from the Hell Creek and Lance Formation excluding Avialae. Let me add that the lack of a large dataset or complete specimens leaves many unanswered questions for many of these genera. New discoveries will be needed to firm up a any listing of the fanual listing Tyrannosauridae: - Tyrannosaurus rex (Osborn 1905) - Nanotyrannus lancensis (Bakker et al. 1988) - Aublysodon mirandus (Not Valid) Alverezauridae: - Trierarhunchus prairiensis (Fowler et al. 2020) Ornithomimidae: - Struthiomimus sedens? (Marsh 1982) - Ornithomimus velox (March 1890) Caenagnathids: - Anzu wyliei (Lamanna et al. 2014) - Caenagathid indet. including Leptorhynchos (Discussion with P. Larsen multiple additional species probably exist and fragmentary material is known) Dromaeosauridae: - Acheroraptor temertyorum (Evans et al. 2013) - Dakotaraptor steini (DePalma et al. 2015) - Dromaeosaurid indet. (Discussion with P. Larsen and the fact that numerous isolated teeth & foot claws exist which do not fit the other two taxons) - Microraptoria indet. ? (Based on isolated bones in my collection ID as possible by prominent paleontologist, also known from North American Campanian deposits) Troodontidae: - Pectinodon bakkeri (Carpenter 1982) - cf Troodon formosus - cf Zapsalis abradens (not valid) Other Theropods: - cf Richardoestesia gilmorei - cf Richardoestesia isosceles - cf Paronychodon lacustri Ankylosauria: - Ankylosaurus magniventris (Brown 1908) - Denversaurus schlessman (Bakker 1988) - cf Gilyptodontopelta (Nodosaur)(Partial skeleton exists and in the process of being studied by a major museum) (have an isolated osteoderm in my collection, its very distinctive) Pachycephalosauria: - Pachycephalosaurus wyomingensis (Gilmore 1931) - Sphaerotholus buchholtzae (Williamson et al. 2002) - Platytholus clemensi (Horner et al. 2023) Ceratopsidae: - Leptoceratops gracilis (Brown 1914) - Leptoceratops sp. (BHI fragmantry material) - Tatankaceratops sacrisonorum (Ott & Larsen 2010) - Torosaurus latus (Marsh 1891) - Triceratops horridus (Marsh 1889) - Triceratops prorsus (Marsh 1890) Others more problematic: - Triceratops sp 2 (Fowler 2017) (MOR 3027 Yoshi specimen) - ?Chasmosaurine MOR 1122 7-22-00-1 - ?Ceratopsian indet. (skulls floating around that are claimed to be a new species including: Nedoceratops hatcher, Lance Fm and Duranteceratops, Hell Creek Fm) Hadrosauridae: - Edmontosaurus annectens (Lambe 1917) - ?Lambeosaurine (Based on a large humerus) Thescelosauridae: - Thescelosaurus neglectus (Glmore 1913) - ?Thescelosaurus gabanii (Morris 1976) (Based on fragmentary material) (A poster was presented at the SVP 2022 meeting of two T. neglectus skulls identified as Male and Female...T gabanii?) Crocodylia: - Borealosuchus sternbergii (Brochu 1997) - Brachychampsa montana (Gimore 1911) - Thoracosaurus neocesariensis (de Kay 1842) - ? Prodiplocynodon langi (Mook 1941)
  7. FF7_Yuffie

    Lance Formation Tyrannosaur Tooth

    Hello everyone, Any thoughts on this Tyrannosaur tooth? It is just over 1 inch long, from Lance Formation, Weston County, Wyoming. It is one I bought years ago -- labelled as Albertosaurus, but given the formation, clearly not. But is it a Nano or a Rexy? cheers
  8. PaleoZorryn

    Lance Formation Bone Id

    Hello fellow fossil hunters, I have a bit of a problematic guess here. I have a bone from the Lance Formation of Wyoming and need some help IDing it. It seems to resemble something like a crocodile coracoid, but not as spot on as I hoped it would. If you have any suggestions I would be glad to here them. Appreciate the help and if you have identified my mystery bone, please send sources to how you know what bone it is. Never will pass an opportunity to learn. Thank you.
  9. Hello, does anyone know some of the described soft shell turtles from the Lance Formation? Or a paper of some of the turtles. I am interested in a soft shell turtle from the Lance so any help is appreciated. Thanks.
  10. Troodontids certainly are one of my favorite dinosaur families. Intelligent and what a set of chompers to eat you with, all you can ask for in a cool dinosaur. Will start this with the Pectinodon teeth in my collection and will continue to add as I take photos. This species has some of the coolest teeth. Pectinodon bakkeri is the only named Troodontid in the Hell Creek and Lance Formations. This is a tooth taxon and its teeth are significantly much smaller than its big cousin Troodon formosus. Lance Formation Hell Creek Formation A couple of the teeth in matrix are partially rooted which is extremely rare since the teeth are so small Hell Creek Formation - Powder River County Hell Creek Formation
  11. Bird and Pterosaur material is extremely rare in the Hell Creek and Lance Formations. Over the years I've purchased and found a few bones that I believe fit this category but not certain. Some may be mammal or reptilian. I'm not a bird guy so if you see something that does not seem right please let me know. Not a lot is published so I'm always open to learning. I showed this to a well respected theropod paleontologist and the potential ID's were his thoughts Aviasaurus sp. ID : Hxmendoza
  12. jikohr

    Is this a T-Rex Belly Rib?

    Hi everyone! I have my eye on this piece that is claimed to be a belly rib from a T-Rex from the Lance Formation of Niobara County Wyoming. The seller claims it's robustness positively ids it as rex, but seems to have forgotten to list exact measurements, which I have contacted him about and am awaiting a response which I will post as soon as I get it. Even then, always good to double check these things! Any insight is greatly appreciated as always!
  13. Edited 3/11/23 to better reflect current info. I've recently gotten interested into the turtles of the Hell Creek and Lance formations and decided to compile what I've gathered onto here. It's amazing to see how many different species have been described from these deposits. I've also tried to attach links to papers that talk about these turtles (at about 22 species!). If I've gotten anything wrong or missed anything please let me know! Adocidae: Adocus sp. (part30043.pdf) listed as being present Baenidae: (https://www.researchgate.net/publication/283851398_A_Review_of_the_Fossil_Record_of_Turtles_of_the_Clade_Baenidae) "Baena" hayi Boremys pulchra (https://www.researchgate.net/publication/241730757_Anatomy_and_relationships_of_the_turtle_Boremys_Pulchra_Testudines_Baenidae) (https://www.researchgate.net/publication/362931080_Stratigraphic_range_extension_of_the_turtle_Boremys_pulchra_Testudinata_Baenidae_through_at_least_the_uppermost_Cretaceous) Cedrobeana putorius (A_Revision_of_Plesiobaena_Testudines_Baenidae_and_.pdf) Eubaena cephalica (https://www.researchgate.net/publication/326165618_A_Description_of_the_Skull_of_Eubaena_Cephalica_Hay_1904_and_New_Insights_into_the_Cranial_Circulation_and_Innervation_of_Baenid_Turtles) Eubaena hatcheri Gamerabaena sonsalla (https://www.researchgate.net/publication/238706760_A_New_Baenid_Turtle_from_the_Upper_Cretaceous_Maastrichtian_Hell_Creek_Formation_of_North_Dakota_and_a_Preliminary_Taxonomic_Review_of_Cretaceous_Baenidae) Hayemys latifrons Peckemys brinkman (see Cedrobaena) Palatobaena cohen Saxochelys gilberti (https://www.researchgate.net/publication/336314521_A_new_baenid_turtle_Saxochelys_gilberti_gen_et_sp_nov_from_the_uppermost_Cretaceous_Maastrichtian_Hell_Creek_Formation_sexual_dimorphism_and_spatial_niche_partitioning_within_the_most_speciose_group_o) Stygiochelys estesi (https://digitallibrary.amnh.org/handle/2246/2652?show=full) Thescelus insiliens Chelydridae?: Emarginachelys cretacea (https://www.biodiversitylibrary.org/part/17248) Compsemydidae: Compsemys victa (https://www.researchgate.net/publication/232688551_Cranial_Anatomy_and_Phylogenetic_Placement_of_the_Enigmatic_Turtle_Compsemys_victa_Leidy_1856) Kinosternidae: Hoplochelys clark (https://www.researchgate.net/publication/226429911_A_new_kinosternoid_from_the_Late_Cretaceous_Hell_Creek_Formation_of_North_Dakota_and_Montana_and_the_origin_of_the_Dermatemys_mawii_lineage) Sinemydidae?: Judithemys backmani (https://www.researchgate.net/publication/232696535_Macrobaenidae_Testudines_Eucryptodira_from_the_Late_Paleocene_Clarkforkian_of_Montana_and_the_Taxonomic_Treatment_of_Clemmys_backmani) Nanhsiungchelydidae: Basilemys sinuosa (B023a33.pdf) listed as being present Trionychidae: Axestemys infernalis (https://www.researchgate.net/publication/337382811_A_new_species_of_trionychid_turtle_Axestemys_infernalis_sp_nov_from_the_Late_Cretaceous_Maastrichtian_Hell_Creek_and_Lance_formations_of_the_Northern_Great_Plains_USA ) (https://www.researchgate.net/publication/260636886_Giant_fossil_soft-shelled_turtles_of_North_America) Hutchemys sterea (https://escholarship.org/uc/item/6090612k) Hutchemys walkerorum (https://www.sciencedirect.com/science/article/abs/pii/S0195667122000362) Helopanoplia distincta (https://peerj.com/articles/4169.pdf) Gilmoremys lancensis ( https://www.researchgate.net/publication/259887738_New_Material_of_Gilmoremys_lancensis_nov_comb_Testudines_Trionychidae_from_the_Hell_Creek_Formation_and_the_Diagnosis_of_Plastomenid_Turtles)
  14. Hello! As I've gone through what I've collected this past summer, I'm finding really interesting things that I took home with me. These come from Niobrara County in Wyoming. I've taken pics of various angles of the fossils. Scale bar has inches (top) and cm (bottom). I'm not completely sure what some of these pieces are so any ideas or suggestions would be helpful. Thanks in advance! Set 1: Vertebral Process Is it possible to ID a process this broken up? I'm thinking it's Edmonto but really holding out for Triceratops Set 2: Triangular bone A friend suggested it might be a Triceratops epoccipital so I wanted to see what you all think Set 3: Skull fragments? There's a lot of blood vessels that would've run through these bones. I'm thinking they might be Triceratops frill (haha can you tell I want some Trike material?) Any thoughts or should I leave the ID at unknown? Either way, they look really interesting. Set 4: Scute? I don't see an identifiable pattern on it but that line running through it makes me think turtle scute. Set 5: Unknown I'm not sure what these are. They both have a really interesting textures running on the surface and they are very thin. Set 6: Jaw piece? Finally, this neat piece that I found on an ant hill. Looks like a jaw piece to me but not holding my breath.
  15. There are two Tyrannosaurs described in the Hell Creek & Lance Formations, Tyrannosaurus rex and Nanotyrannus lancensis. Teeth from these animals are the number one sought after and coveted item by collectors. I don't understand all the hoopla and prices they command since my friends who I collect with know that I'm not a tooth person and prefer bones and claws. However I've been fortunate to find and acquire a few teeth and will post a several of my nicer ones. My two most favorite T-rex teeth are my biggest and smallest: The Baby (one of the rarest teeth around) is 1 1/8" and when I showed it to Bob Bakkar and Pete Larson they flipped and never had seen a Rex tooth so small and confirmed it was one. Collected from Garfield County, MT. My big Trex one is a rooted Premaxillary tooth at 6". One can see the replacement tooth hole at the bottom of the root T-rex teeth are big and my biggest crown, no root still on the matrix is this 4 5/8" monster. If your are interested none of these teeth have any work done to them. Minor crackfill to the root of the 6" tooth. Serrations are in pretty good shape. .
  16. Consolidated all my informational Topics to make it easier to reference. Will keep updating since some of the reference material is outdated. Have to thank @PFOOLEY for suggesting this consolidation and it makes it a lot easier for me to access these topics as well as our members to know what's out there. General Tips in Buying Theropod Teeth Dinosaur Anatomy 101 Stratigraphy of the Late Cretaceous in North America Best Books for Dinosaur Identification Rare Theropod Teeth (World Wide) Identification of Some rarer Theropod Teeth Triassic Identification of Dinosaur Teeth from the Triassic of New Mexico Jurassic: Morisson Formation Identification of Theropod Teeth Quick Guide To Sauropod Teeth Tips in Buying a Sauropod Foot Claw Ornithischians from the Morisson Formation Jurassic: Europe Dinosaurs of Costal Portugal Jurassic Theropods of Germany Cretaceous: USA Hell Creek & Lance Formation Fanual List Identification of Theropod Teeth in the Hell Creek and Lance Formations Identification of Troodontid Teeth Identification of Tyrannosaurid Teeth From USA & Canada Identification of Ankylosaurid Teeth Identification of Acheroraptor Teeth Identification of Hadrosaur Teeth Identification of Claws and Ungals from the Hell Creek and Lance Formations Identification of Pachycephalosaurid and Thescelosaurus Teeth Tooth Features in Tyrannosaurids The Case for Nannotyrannus Dakotaraptor Teeth and Claws Hell Creek Fm Identification of Bones /Claws from Alvarezsaurids from North America Hell Creek Faunal Representation Identification of Theropod Teeth from Judith River Formation ( Campanian ) Includes Faunal List Fanual List from the Two Medicine Formations . Theropod Assemblage of New Jersey Cretaceous: Kem Kem of Morocco Kem Kem Theropod Teeth Kem Kem Theropod Tooth Morphology Identification of Sauropod Teeth from the Kem Kem Tips in Purchasing a Spinosaurid Hand Claw Identification of Claws from the Kem Kem Identification of Spinosaurid Jaws from the Kem Kem Guide to Help Purchase Rooted Moroccan Theropod Teeth Pterosaur Teeth from Kem Kem Republic of Niger Identification of Theropod Teeth Thailand Identification of Spinosaurid Teeth Cretaceous: South America Patagonia's Theropod Teeth Cretaceous: Uzbekistan: Identification of Theropod Teeth: Uzbekistan Sauropod Teeth: Uzbekistan Cretaceous: Europe Identifying Baryonyx Teeth
  17. Updated March 29, 2023 Changed information on Avisaurus archibaldi A few years ago most of the smaller theropod teeth from the Hell Creek/Lance Formations were identified based on teeth from the Campanian assemblages of North America. Over the past couple of years new discoveries have shed new light on the theropods of the end of the cretaceous and new species have been described. I have addressed these on separate topics but decided to put all of these together to get a better view of the current picture of the upper Hell Creek and Lance formations. If you see any omissions or errors feel free to let me know. Tyrannosaurids: Under Topic: Identification Tyrannosaurid Teeth From North America - General Fossil Discussion - The Fossil Forum Dromaeosaurids: There are two described in the Hell Creek Acheroraptor temertyorum and Dakotaraptor steini however there is mounting evidence that an additional one, mid-size, is present. Saurornitholestes and Dromaeosaurus species are not present. Acheroraptor temertyorum Identification: Like all Dromaeosaurid teeth the denticles are key and different between those on the anterior and posterior carinae. You should easily be able to see that the posterior ones are much larger. If the denticles are identical its probably a juvenile Nanotyrannus tooth. Secondly there are apicobasal ridges on the crown which are diagnostic to this species. There can be several on either side and fewer on posterior located teeth. The teeth are recurved and typically under 1/2" (13mm) long. Dakotaraptor steini Identification: Zapsalis sp. (UPDATE) Identification: Similar to Z. abradens from the Judith River Formation. Very compresses tooth with rounded serrations on the distal side and a smooth mesial edge. One flat tooth surface with longitudinal ridges This form of tooth has been identified as a premaxillary tooth on Saurornitholestes in Alberta. So these teeth should most likely be assigned to Archoraptor but will need new discoveries to confirm it. Update: The unserrated form of this tooth (paronychodon morph) may also be a premaxillary tooth of a Dromaeosaurid or Troodontid. New discoveries are needed to properly assign it. Troodontids: There are at least two present cf Troodon formosus and Pectinodon bakkeri. but only one described Pectinodon bakkeri. cf T. formosus is an easily recognizable tooth. Denticles strongly hooked and turned toward the tip Pectinodon bakkeri significantly smaller 6mm or less than Troodon teeth. Comb like denticles on posterior carina, lacking on the anterior side.. Positionally these teeth have different morphologies can been see in the photo. Reference from : Vertebrate Microfossil Assemblages by Sankey and Baszio Other Teeth: cf Paronychodon lacustris type teeth have several morph types are flat on one side and usually bear three or more longitudinal ridges. Another morp type can be seen in the image. The other side is convex and can be smooth or longitudinal ridges can be present as well.. This is a tooth taxon so placement is questioned by many. May be a Theropod or Pterosaur cf Richardoestesia gilmorei. These teeth may have two different morphologies and can include a long form whose serration density is very high. The information provided is the standard morphology. What is shown comes from the Larsen/Currie's paper. Data they used is from Longrich 2008. Taxonomic placement of these teeth is uncertain. Study included 33 teeth from the Lance & Hell Creek Formation - not all data was collected on these teeth CH Avg: 5.9 mm (Range 3.6 to 10) CBL Avg (14 teeth) 3.8 (Range 2.1 to 4.0) CBW Avg (14 teeth) 1.5 (Range 1.1 to 1.8) CBR: Avg (14 teeth) 0.40 CHR: Avg (33 teeth) 1.60 Density (16 Teeth) Distal: 6.75 (5/mm) or 1.4 mm. Mesial: 9.4 (5/mm) or 1.88 mm DSDI : 1.39 Other Characteristics - Rounded small denticles - Slight posterior recurve Photo Scale Bar : 1 mm References: Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time Derek W. Larson, Philip J. Currie 2013 Longrich NR (2008) Small theropod teeth from the Lance Formation of Wyoming, USA. In: Sankey JT, Baszio S, editors. Vertebrate Microfossil Assemblages: Their Role in Paleoecology Richardoestesia isoceles. Typically are very compressed, elongated and form an isosceles triangle. Fine serrations can be present This species along with the Paronychodon is currently under study and will most likely be described to a new taxon which may not be dinosaurian . Albertonykus sp. is known from bones. Its teeth are very small and pointed. Photo of tooth is from the smaller Mongolian species Mononychus olecranus Morph types isolated small theropod teeth are abundant in these assemblages. Morph types exist and determining the taxonomic affinities of these teeth is problematic. So be prepared to identify these teeth as Theropod indet. Note A lot of what I've described here requires a detailed examination of the serrations. The crisper they are on your tooth the better the opportunity you will have to identify them. having some magnification capability helps Bird: Avisaurus archibaldi This tooth is typically sold as A. archibaldi. Unfortunately this morphology of tooth is most likely Crocodilian per a recent publication, see attached topic. A slightly different morphology pointed out in the paper is viewed as most likely Avian
  18. Jurassicbro238

    Lance Formation Fossil ID

    I was able to dig in the Lance Formation last summer and finally got the chance to look at this find more closely. I don't think this is a dinosaur fossil and I'm not familiar with the skeletal anatomy of the other vertebrates at the site. Anyone know what it is? I tried taking all the relevant angles. This one came from Niobrara County in Wyoming if that helps.
  19. DSMJake

    Lance Formation Trunk Cast

    Need some help from our plant experts. This is a 3D trunk cast that I found in the Lance Formation. There’s plenty online regarding leaves, but I couldn’t find anything regarding trunk identification. Thanks!
  20. ThePhysicist

    Meniscoessus tooth

    From the album: Hell Creek / Lance Formations

    Meniscoessus was a large multituberculate mammal (large by Cretaceous standards), identified by the crescent-shaped/grooved cusps. Looks like a right M2 (right 2nd lower molar).
  21. ThePhysicist

    T. rex tooth chunk

    From the album: Hell Creek / Lance Formations

    For most collectors, it's more affordable to have a piece of a T. rex tooth if you just want it represented. This one is clearly T. rex: it's theropod with serrations (this one has the basalmost portion of the mesial carina), very thick, and clearly would've had a large circumference. Note also the large angle made by the curvature of the tooth at the carina (not Nanotyrannus which have narrow, blade-like teeth).
  22. These are multituberculate teeth found in the lance formation, I have yet to identify all of them and would like some insight. I have to post these in groups because there are so many but I can share the animals I think show the closest resemblance.
  23. Lydia.K.Tyree

    Lance formation teeth

    These are photos of an unidentified tooth from the lance formation in Wyoming, it was put in a group of mammal teeth all approximately in the range of 2-4 mm in size. Among the teeth two of them have been identified as shark, one is a Lissodus and the other is unknown as of now. If there are any ideas as to what this tooth could be please do share.
  24. Nanotyrannus35

    Lance Formation Toe Bone?

    While looking through my Lance Formation matrix, I'd found this strange bone that looks like it might be a toe bone. Here are the pictures. The scale is in millimeters and the specimen is from Weston county, Wyoming. Thanks for any help.
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