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Showing results for tags 'hell creek formation'.
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From the album: Hell Creek / Lance Formations
A river-worn, shed Ornithischian dinosaur tooth found in a channel deposit. Despite its rough shape, the prominent central ridge and denticles make me think it's Pachycephalosaurid. -
Identification Though smaller than many imagine T. rex teeth to be, this is indisputably one. It is characteristically robust, and has chisel-shaped denticles with similar denticle densities on each carina.1 Those qualities support its identification as a Tyrannosaurid, and with the locality information confirming it originated from the Hell Creek formation, this must be T. rex. Comments Like most isolated theropod teeth, this is a shed tooth, likely lost during feeding.2 This specimen has exquisite preservation with the enamel texture sharply retained as in life. It however has minor weathering with possible feeding wear at the tip, light root etching, and the base of the tooth has been lightly smoothed possibly by tumbling in an ancient river (enamel is harder so it wouldn't have weathered as much as other portions of the tooth). References 1. Smith, Joshua B. “Heterodonty in Tyrannosaurus Rex: Implications for the Taxonomic and Systematic Utility of Theropod Dentitions.” Journal of Vertebrate Paleontology, vol. 25, no. 4, 2005, pp. 865–87. JSTOR, http://www.jstor.org/stable/4524513. 2. Fiorillo, Anthony R., and Philip J. Currie. “Theropod Teeth from the Judith River Formation (Upper Cretaceous) of South-Central Montana.” Journal of Vertebrate Paleontology, vol. 14, no. 1, 1994, pp. 74–80. JSTOR, http://www.jstor.org/stable/4523546.
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This is probably a long shot but I figure I’d post it anyway because I’m really not sure what bone this chunk could be from… This is a large chunk of bone (over 15 cm in diameter) from the Hell Creek Formation with a unique shape. A personal find. It’s rounded on one end but tapers at the other, however at the tapering end it’s fairly obviously broken whereas the rounded end appears to simply be weathered. One side is convex like a dome whereas the other side is concave like a bowl. The entire piece is heavily weathered, although there is some intact cortical bone in the concave side. Convex side: Concave side: Thickness: I’ve only ever seen pictures of herbivore unguals, so I’m not sure how well this piece actually matches their shape. If it is an ungual my guess would be Edmontosaurus. Can anyone confirm or deny? And, if not an ungual, any guesses as to what bone or taxon this could be from, or should I leave it in the “chunk-o-saurus” bin? Much thanks.
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From the album: Hell Creek / Lance Formations
A rooted Ceratopsid tooth - either Triceratops or Torosaurus (though it's more likely to be Triceratops since it was far more abundant in the HC ecosystem). -
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.
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Big News, a new Pachycephalosaurid from the Hell Creek Formation Platytholus clemensi. It's intermediate in size between the small-bodied Sphaerotholus and the largest Pachycephalosaurus Paywalled https://www.tandfonline.com/doi/full/10.1080/02724634.2023.2190369#.ZDm0HAS1AH0.twitter
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Just want to get some opinions before I purchase a tooth. Do you guys think this is definitely a Dakotaraptor tooth? Or does it look more Nano? Size is .71” and it’s from Hell Creek Formation, Garfield County, Montana. 24506BD7-17AC-42BF-B3C6-7C613A84332B.webp 31C05BFB-8621-4C95-9A7A-4A92A0C553D7.webp E6280DD3-5623-4D78-966F-F7A20751CEFB.webp 7CFB9AAF-269D-48B6-A26E-5265AE476524.webp E04ED762-40B5-42D1-BADA-52A77A44425B.webp
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Found this in the Hell creek formation in eastern montana. It measures 2 7/8” long by 3/4” wide. It definitely is not crock. Leaning towards paraxenisaurus. “Strange lizard”. It would be rare in the Hell Creek.
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From the album: Hell Creek / Lance Formations
Cimolodon nitidus Hell Creek Fm., Meade Co., SD, USA M1 (1st upper molar) While you may have mistaken it for a rodent, Cimolodon belonged to a far more ancient and wildly successful group of mammals, the multituberculates (so named for the multiple cusps arranged in rows on their molars). It likely ate seeds and nuts which were handedly ground by its lego-shaped molars. Cimolodon had to be wary of the likes of Pectinodon or other small predatory dinosaurs in the Hell Creek ecosystem. Unlike a few other contemporaneous mammals, this cousin of ours did not survive the K-Pg extinction event and perished along with the non-avian dinosaurs.-
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Unusual Hell Creek Formation fossilized tooth record
Joseph Fossil posted a topic in Questions & Answers
I've recently found a, how do I say...quite unusual Theropod dinosaur tooth from the Late Cretaceous Hell Creek Formation (67-66.0 Million Years ago). The paper, titled The occurrences of vertebrate fossils in the Deadhorse Coulee Member of the Milk River Formation and their implications for provincialism and evolution in the Santonian (Late Cretaceous) of North America by Derek Williams Larson, is a record of theropod teeth from various Late Cretaceous formations in Western North America, and buried on page 244 of the report an apparent megalosauridae tooth (UCMP120305) from the Hell Creek Formation (67-66.0 Million Years ago). https://era.library.ualberta.ca/items/54e305be-de2a-4529-adc9-4e6b038ae699/view/28ba15f8-8131-44be-b48f-e4e9648db26e/Larson_Derek_Fall_2010.pdf This for me is pretty unusual as Megalosauridae (as far as we know) lived only between the Middle-Late Jurassic (170-145 Million Years ago), millions of years before the Maastrichtian Cretaceous. I know in the past many theropod dinosaurs were described as species of "Megalosaurus", but that was more around the 1800-early 1900s and the citation for the tooth lists its apparent phylogenetic description as recently as 2008. There was also another less confusing but fascinating description of a Dromaeosauridae tooth (UALVP48462) from the Milk River Formation, which apparently has a tooth crown height of 17.3mm. But besides the pretty fascinating Milk River Dromeosauridae tooth, I'm puzzled about the UCMP120305 specimen! I really skeptical this tooth specimen belongs to megalosauridae. But if it's not, then where could the classification of the specimen have come from? What do you guys think?
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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.-
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Curious about iron and pyrite in the Hell Creek Formation
Maniraptora posted a topic in Questions & Answers
Hey all! When I went on a collecting trip in the Hell Creek Formation in Montana, there were many iron concretions, and I've noticed that some specimens from there appear to be iron-stained. This makes me wonder if pyrite could be among the minerals involved in fossil preservation there. Are some of the bones found in the Hell Creek pyritized, and how could those be distinguished from others preserved differently? If so, do those Hell Creek specimens ever develop "pyrite disease," and what would be the warning signs to look out for? Thanks so much for sharing your knowledge! -
Identification Teeth of Nodosaurids are often confused for those of their rarer relatives, the Ankylosaurids, namely the archetypical Ankylosaurian, Ankylosaurus. (Most) teeth of Ankylosaurus are taller than they are wide, are generally conical in shape with one side flatter than the other, have large denticles on the anterior and posterior edges (6-8 anterior, 5-7 posterior), and have swollen/bulbous bases. Tooth wear is normally on the crown face, compared to wear on the tip (apex) as in Nodosaurids.1,2 Comments This tooth is partially rooted; the root is cylindrical and hollow. There is a wear facet on one side, offset from the center, with grooves roughly perpendicular to the apicobasal axis (suggestive of the mastication motion). This tooth was found in the same county as the holotype of this species. References 1. Carpenter, K. "Redescription of Ankylosaurus magniventris Brown 1908 (Ankylosauridae) from the Upper Cretaceous of the Western Interior of North America." Canadian Journal of Earth Sciences (2004), 41(8): 961-986. https://doi.org/10.1139/e04-043 2. Carpenter, K. "Baby dinosaurs from the Lance and Hell Creek formations and a description of a new theropod." Contributions to Geology (1982), 20: 123–134.
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Identification Troodontid teeth may be identified by their exaggerated, triangular, apically directed posterior denticles1. Pectinodon bakkeri is the only Troodontid species currently named from Lancian strata; its teeth are on average smaller and more gracile than those of its cousin, Troodon. Comments Pectinodon (meaning "comb-tooth")1 is a tooth taxon, since no remains attributable to the genus beyond teeth have been found. Pectinodon seems to be a rare member of the Hell Creek fauna, with their teeth being fairly uncommon. It was a small theropod, with teeth that couldn't handle stresses as well as their Dromaeosaurid and Tyrannosaurid relatives2. This coupled with their small size suggest that Pectinodon was a small/soft prey specialist, preferring the rodent-sized mammals of the time, lizards, insects, etc. Some researchers have proposed omnivory as a possibility for Troodontids (cf. Holtz et al. (1998))3. References 1. Carpenter, Kenneth. "Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of en new species of theropod." Contributions to Geology 20.2 (1982): 123-134. 2. Torices A, Wilkinson R, Arbour VM, Ruiz-Omeñaca JI, Currie PJ. "Puncture-and-Pull Biomechanics in the Teeth of Predatory Coelurosaurian Dinosaurs." Curr Biol. 2018 May 7;28(9):1467-1474.e2. 3. Holtz TR Jr, Brinkman DL, Chandler CL. "Denticle morphometrics and a possible omnivorous feeding habit for the theropod dinosaur Troodon." Gaia. 1998; 15: 159–166.
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Hello everyone, I recently finished preparing some ribs that I posted in the fossil preparation category and am having some trouble IDing them. One is fairly complete and the other 2 are fragments. They were found grouped together in Garfield County, Montana on a ranch. I think they resemble some Thescelosaurus ribs that I've seen in some papers but not enough to be confident in assigning an ID. Here are front and back views of each rib individually. I also found numerous bits of other bones in the jacket one of them being what I think is a carpal of something but haven't had time to do much digging. Here are some top and bottom views. I know you've said ribs are tricky to ID @Troodon but if you have any insight it would be very appreciated. Thank you all for your time and help.
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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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From the album: Hell Creek / Lance Formations
Pectinodon (meaning "comb-tooth") is a tooth taxon, since no remains attributable to the genus beyond teeth have been found. Pectinodon seems to be a rare member of the Hell Creek fauna, with their teeth being fairly uncommon (though being so small, I'd guess that few people actively search for them). It was a small Troodontid theropod, with teeth that couldn't handle stresses as well as their Dromaeosaurid and Tyrannosaurid cousins (Torices et al. (2018)). This coupled with their small size suggest that Pectinodon was a small/soft prey specialist, preferring the rodent-sized mammals of the time, lizards, insects, etc. Some researchers have proposed omnivory as a possibility for Troodontids (cf. Holtz et al. (1998)). Troodontids famously are regarded as among the most intelligent dinosaurs for their large brain size / body size ratio. This notion serves as fodder for speculation that had the dinosaurs not gone extinct, Troodontids (Pectinodon being (one of?) the last) would have continued to grow in intelligence and develop sentience and civilizations. Troodontid teeth like Pectinodon can be easily identified by their small size, exaggerated, triangular, apically oriented posterior serrations.-
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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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From the album: Hell Creek / Lance Formations
One of my favorites as a kid - the archetypical Ankylosaurian - Ankylosaurus. Ankylosaurus teeth appear to be fairly uncommon in Hell Creek - some paleontologists have suggested that Ankylosaurus may have lived in the highlands or nearer the coast of Laramidia. Most "Ankylosaurus" teeth you see for sale are actually Nodosaurid (cf. Denversaurus), for whatever reason, they seem to be far more common. Ankylosaurus teeth also often have wear facets, as this one does. The denticles give their teeth a "leaf-like" appearance. Given their shorter stature, Ankylosaurians probably were low-browsers. This one was found by a rancher last year, and was rediscovered and prepped out of the matrix in October.- 1 comment
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Dinosaur & Croc Faunal List of the Hell Creek and Lance Formations
Troodon posted a topic in Questions & Answers
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)- 34 replies
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From the album: Dinosaurs
Plant roots often intrude upon a fossil's resting place, leaving behind white streaks when removed. -
From the album: Dinosaurs
A rare tooth from the Hell Creek formation. Curiously most Ankylosaurian teeth you see online are actually Nodosaurid. This one is the Ankylosaurus. -
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.
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