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Showing results for tags 'hell creek formation'.
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From the album: Hell Creek / Lance Formations
As a theropod tooth aficionado, I thought it useful to compare two families present in the Hell Creek Formation. They become increasingly difficult to distinguish as they get smaller, but this graphic presents some features which may be used to differentiate them on two similarly-sized exceptional specimens. Keep in mind there is some variability due to position, ontogeny, etc., so it's beneficial to study more than one tooth for each family.-
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From the album: Hell Creek / Lance Formations
Not the prettiest tooth, but I very much enjoy fossils like this that demonstrate behavior and tell a story. T. rex and other Tyrannosaurs were unusual among theropods in that they consumed the entire carcass of an animal - bones and all. Most theropod dinosaurs have ziphodont teeth, thin and knife-like, good for cutting muscle from bone. The thick and robust teeth of adult Tyrannosaurs, coupled with their incredible bite force, allowed them to shatter and pulverize bone - even those of the large, formidable herbivores they hunted. Despite the robustness of their teeth, Tyrannosaurs often broke them in the process of biting. It may have been a while before the broken tooth was replaced by a new one, so in the meantime, the broken tooth would continue to accumulate wear. This is one such tooth, a large portion of the tooth was broken off when the animal bit into another dinosaur, and it was still used afterwards for some time before it was replaced. Based on the placement and extension of the carinae to the base of the tooth, and the size, this was an anterior tooth (at the front of the mouth, probably the first dentary tooth) of an adult individual. See Schubert & Ungar (2005) for a discussion on Tyrannosaur tooth wear features (open-access). -
From the album: Hell Creek / Lance Formations
Not the prettiest tooth, but I very much enjoy fossils like this that demonstrate behavior and tell a story. T. rex and other Tyrannosaurs were unusual among theropods in that they consumed the entire carcass of an animal - bones and all. Most theropod dinosaurs have ziphodont teeth, thin and knife-like, good for cutting muscle from bone. The thick and robust teeth of adult Tyrannosaurs, coupled with their incredible bite force, allowed them to shatter and pulverize bone - even those of the large, formidable herbivores they hunted. Despite the robustness of their teeth, Tyrannosaurs often broke them in the process of biting. It may have been a while before the broken tooth was replaced by a new one, so in the meantime, the broken tooth would continue to accumulate wear. This is one such tooth, a large portion of the tooth was broken off when the animal bit into another dinosaur, and it was still used afterwards for some time before it was replaced. Based on the placement and extension of the carinae to the base of the tooth, and the size, this was an anterior tooth (at the front of the mouth, probably the first dentary tooth) of an adult individual. See Schubert & Ungar (2005) for a discussion on Tyrannosaur tooth wear features (open-access). -
I have this very tiny tyrannosaurid tooth from hell creek formation, south dakota. Im wondering if it's possible to know if the tooth is from a infant nano or t-rex? Distal serration density: about 6/mm Can't see any intact serrations on the mesial side. Crown Height: 4 mm Crown base-lenght: 2,5 mm Crown base-width: under 1 millimeter, about 0,8 mm to roughly estimate (very hard to measure this one).
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Hello, Heres another chunk of interesting-looking bone for which curiosity has finally gotten the best of me. This is a piece I picked up in 2021 on my summer dig at the Hell Creek Formation in Montana. I feel there’s a chance this piece might be identifiable. This piece of bone is bowl-shaped with a strange web-like texturing on the convex side. The edge of the bone which is not broken is rounded and almost flower petal like. There is a set of T-shaped rounded ridges on the concave side. Not the best quality bone either, with significant siderite encrustation being present. I have a few wild ideas about what this might be but want to hear some unbiased opinions. Any ideas and help is much appreciated.
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My Spring trip this year was quite a challenge. Last year we had oppressive heat, it was extremely dry with high winds. This year it was rain, rain and more rain and cool. The ranchers however are in heaven with pastures that are green, green and green. Hopefully it continues for them through the summer. So, we had a few rainout days, lots of drizzle and had to deal with gumbo feet, slippery cliffs and wet bones and matrix. Not the best of conditions for collecting and the group's results showed that. On the downside the day we departed Belle Fouche, where we stay, a very bad storm hit with tennis size hail, 70mph winds and lots of flooding. Unfortunately, there was lots of damage to homes, businesses, vehicles and roadways. Lots of work getting that community back to normal. I'll start with the down days. Visited the BHI to dropoff some specimens. Pete Larsen is currently doing a study on the number of Leptoceratops that exist in the HC formation and wanted to see my maxillae to cast and study. He showed us skull elements that pointed too two distinct species. These are most likely associated since they came from the same deposit. Pete showed us a beautiful replica, that he recently acquired, of Raptorex which is a dubious dinosaur. It's actually a juvie Tarbosaurus. BTW the juvie bones are identical to an adult one. Hmm Trex and Tarbo are very closely related...so does that mean that juvie T rex bones would be similar to that of an adult. A new Stan replica was getting ready to be put together A visit to the Carter County museum is a must on a rainy day Their Anatotitan Dinosaur - actually an old Edmontosaurus Triceratops T rex Nanotyrannus Jane
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From the album: Hell Creek / Lance Formations
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From the album: Hell Creek / Lance Formations
A young T. rex tooth. The preservation of the enamel is fantastic, and I like the dark hues. The serrations are also in great shape. There is some minor feeding wear on the tip. -
From the album: Hell Creek / Lance Formations
Sold by the BHI as Nanotyrannus lancensis. However, given the uncertain status of Nanotyrannus' validity, I chose to label it as Tyrannosaurid for now. It is interesting to compare to my other small Tyrannosaur teeth of the same/similar position. The base is clearly more compressed than my baby rex tooth (which is also smaller). -
From the album: Hell Creek / Lance Formations
A Tyrannosaur tooth from Eastern Montana. Given the basal "pinching," this would be Nanotyrannus lancensis if it's valid (otherwise it's T. rex). Interesting to compare it to my other small Tyrannosaur teeth. The tip was probably broken after fossilization, but the gouges on the labial face may be inflicted while the tooth was in use. Note that the enamel is well-preserved with sharply resolved texture and is still clear. -
From the album: Hell Creek / Lance Formations
Sold as Triceratops sp. by the BHI. Normally, Ceratopsid teeth should be considered indeterminate since the teeth of the large-bodied Ceratopsids present in the Hell Creek fauna are virtually indistinguishable. Trusting the ID of the BHI would be to label it as Triceratops sp., but to be conservative (and since I don't know their reasoning behind the ID), I chose to label it as Ceratopsidae cf. Triceratops sp. -
From the album: Hell Creek / Lance Formations
Unworn Hadrosaur tooth from the maxillary (upper jaw). Based on the size, it could be from a juvenile. -
Ankylosauridae & Nodosauridae Teeth - Can You differentiate?
Troodon posted a topic in General Fossil Discussion
(EDITED 5/24/22) to add an undescribed Nodosaurid to Hell Creek/Lance Fm. I see a lot of misunderstanding on what is being sold online at auctions and dealers sites. Some have it correct but most mix up the terminology. So here is Anky 101 aimed at Novice collectors and I will keep it simple. What you see sold in most markets are teeth from late Cretaceous North American locations mostly Montana, Wyoming and the Dakota's so I will focus on those areas. (Hell Creek, Lance, Two Medicine and Judith River Formations) Teeth from Canadian locations will have similar characteristics. There are two basic families of armored dinosaurs in these regions Ankylosauridae and Nodosauridae. Ankylosaurids are the brutes with big tail clubs. Nodosaurids have no clubs but are fierce looking with big spikes projecting from its sides. You don't want to meet up with either family. So when these teeth come up for sale most are very worn and it can get difficult to ID, so if possible avoid buying those. There is also a variation in the teeth with jaw position. Wear facets are also very common on these teeth. My photographs show complete teeth that have little wear so you can see what they typically should look like. Let me call them your generic teeth and are good representation of these families. There are multiple genus that you run into and the species is dependent on what formation you are in, see below with what is currently understood. Some have yet to be described to a species level due to lack of skeletal remains but teeth are plentiful. Differentiating teeth between the two families is quite easy. For Ankylosaurids crowns are small with long roots with two key characteristics, a bulbous base, see white arrow and a prominent central ridge on SOME species like Ankylosaurus in the Hell Creek others it covers the entire face of the crown. Other examples of North American Ankylosaurids Nodosaur Teeth: Are much larger, both taller and wider than Ankylosaurids, a shelf is visible below a pocket in the crown, no center ridge. Looks like a mit. Hell Creek Formation Two Medicine Fm Undescribed Nodosaur Judith River FM If you are interested in additional reading let me suggest Dinosaur Systematics by Ken Carpenter. Its also a good book describing theropod teeth. Our current understanding of species described: based on the revised analysis by Paul Penkalski, 2018. These views might not be share by some paleontologists but thats normal. Let me also say that with new discoveries and research some of this is subject to change. Hell Creek and Lance Formation Ankylosaurus magniventris (Ankylosaurid) Denversaurus schlessmani (Nodosaurid) Indeterminate Nodosaurid: I have seen enough evidence (partial skeleton) that there exits an undescribed Nodosaurid (cf Glyptodontopelta) Judith River Formation Zuul crurivastator (Ankylosaurid) Undescribed Nodosaur Two Medicine Formation Oohkotokia horneri (Ankylosaurid) Edmontonia rugosidens (Nodosaurid) Dinosaur Park Formation Euoplocephalus tutus (Ankylosaurid) Anodontosaurus lambei (Ankylosaurid) Platypelta coombsi (Ankylosaurid) Scolosaurus thronus (Ankylosaurid) Dyoplosaurus acutosquameus (Ankylosaurid) Edmontonia rugosidens (Nodosaurid) Panoplosaurus mirus (Nodosaurid) Horseshoe Canyon Formation Anodontosaurus lambei (Ankylosaurid) Edmontonia longiceps (Nodosaurid) Oldman Formation Scolosaurus cutleri ? (Ankylosaurid) Undescribed Nodosaurid Revised systematics of the armoured dinosaur Euoplocephalus and its allies Paul Penkalski https://www.researchgate.net/publication/323579149_Revised_systematics_of_the_armoured_dinosaur_Euoplocephalus_and_its_allies
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Excellent paper that provides great insights into Hesperornithiformes. Some of the photos can also aid in identification of isolated elements. https://www.mdpi.com/1424-2818/14/4/267/htm
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From the album: Hell Creek / Lance Formations
Tyrannosauridae (Cf. Tyrannosaurus rex) Hell Creek Fm., Wibaux Co., MT, USA This minute tooth is indeed Tyrannosaur: the mc/dc serration densities are virtually identical, and the denticle shape is not like those of Dromaeosaurids. It also has a slight pathology near the tip. -
For those interested in Dinosaurs from North America here is an excellent presentation on Oviraptorosaurs. Demonstrates how the lack of understanding of ontogeny may have impacted the number of described species. Study is ongoing but may point to multiple caenagnathids in the Hell Creek/Lance Formation. https://youtu.be/TpY9ygiG4ng
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From the album: Dinosaurs
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From the album: Dinosaurs
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From the album: Dinosaurs
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From the album: Dinosaurs
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Here is a small tooth collected from the Hell Creek formation, Garfield Montana, likely a juvenile. I think from its properties that it is a Nanotryannus. I would appreciate your thoughts.
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Thoughts on the identity of this (Hell Creek formation, near Tyrannosaur excavation north of Fort Peck MT)
gneissdinosaur posted a topic in Fossil ID
Hi all, I have some ideas (apart from the usual non-diagnostic dismissal) already but I'm coming back to this after many years because I never could settle on a position. Hell Creek formation, obviously dinosaur, not too far from one Tyrannosaur site from a recent excavation. Might be in MOR collections, don't know, but it was marked for pickup (we were scouting on a day off from the main site). Eroding out of the same slope as an several Edmontosaurus elements I found including a 75% complete scapula from a rather large adult. Any thoughts? My hand (25 cm / 10" span outstretched, so you're looking at something about the size of a smallish melon) for scale as well as the pick. This was pre-smart phone so focus isn't what it could be now. Sadly the associated elements found together (background) did not turn out when I developed the film months later. Note the V-shaped process (broken).
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Identification This is a classic T. rex tooth. It's clearly Tyrannosaurid by its robusticity, similar serration densities on each carina (mesial carina counted by the "roots" of the denticles as they are completely worn off), and chisel-shaped serrations. Those qualities with its locality and formation mean it must be the one and only. Notes The Crown Height Ratio (CHR) suggests a posterior position (it's short and stout). There's evidence of wear on the tip and mesial carina.
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Identification Tyrannosaur teeth characteristically have similar serration densities on each carina, with chisel-shaped denticles. Though small, this tooth matches those qualities, and doesn't resemble other smaller theropods like Dromaeosaurids. Identified as Cf. T. rex based on its similarity to another, larger tooth in my collection. Notes This tooth is from a juvenile individual. Serration densities illustrated in the above photos. There is a slight pathology (bend) near the tip.
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From the album: Hell Creek / Lance Formations
Tyrannosauridae (Nanotyrannus-morph) Hell Creek Fm., Powder River Co., MT, USA A classic Nanotyrannus Tyrannosaur tooth: compressed and blade-like. Exceptional preservation, with a minor wear facet near the tip on the lingual side (indicating it's from the left maxilla). I really like the color.-
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