Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 05/06/2026Amongst collectors and fossil dealers, a common label for this morphology tends to be Dakotaraptor due to its assumed dromaeosaurine affinity and relation to the older Campanian aged Dromaeosaurus albertensis, which is known for serrationless mesial carinae in some tooth positions. 020
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 05/06/2026Of the described theropods, Nanotyrannus can be ruled out as it has serrations on the distal carinae. Saurornitholestines like Acheroraptor are more associated with Zapsalis. It could be a pathological Tyrannosaurus rex or even the controversial Dakotaraptor. Or, it could be none of the above. 020
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 05/06/2026A fossilized dinosaur tooth of an indeterminate theropod from the Hell Creek Formation in East-Central Montana, USA. This morphology, likely a premaxillary tooth, lacks serrations on the mesial carinae. #FossilFriday #dinosaur #fossil #paleontology #tyrannosaurid #dromaeosaurid #theropod 2102
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 29/05/2026A fossilized dinosaur tooth of a Nanotyrannus sp. from the Hell Creek Formation in Powder River County, Montana, USA. Nanotyrannus is not a true tyrannosaurid but a nanotyrannid eutyrannosaur. #FossilFriday #dinosaur #fossil #paleontology #nanotyrannus #tyrannosaurid #theropod 0124
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 22/05/2026A mosasaur tooth, possibly Tylosaurus rex from the Ozan Formation in Fannin County, Texas, USA. This marine lizard, the T. rex, is the largest known tylosaurine mosasaur and one of the largest species of mosasaur. #FossilFriday #mosasaur #fossil #paleontology #tylosaurus 051
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 21/05/2026The recent description of Tylosaurus rex by Zietlow et al. would suggest these large, but younger aged, Ozan Tylosaurus specimens do not belong to Tylosaurus proriger but... T. rex. That said, isolated tylosaurine teeth are quite similar to one another. digitallibrary.amnh.org/items/dbbf9d...digitallibrary.amnh.org 010
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 27/03/2026A group of Permian lungfish tooth plates from the Wellington Formation in Waurika, Jefferson County, Oklahoma, USA. I'm not sure what genus these belong to, but they seem closer to the younger aged Ceratodus than to things like Gnathorhiza. #FossilFriday #fish #lungfish #fossil #paleontology 192
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 20/03/2026The tooth features a notable twist of the mesial carinae which is unusual for theropods in this region. While associated and commonly seen in coelurosaurs, noasaurids I believe can also have this condition. These are occasionally seen amongst common abelisaurids and young carcharodontosaurid teeth. 022
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 20/03/2026A dinosaur tooth of an indeterminate theropod, possibly a coelurosaur from the Kem Kem Group in Morocco. It's hard to say what this tooth belongs to. Megaraptorans are a possibility, as are dromaeosaurids and basal coelurosaurs. #FossilFriday #dinosaur #fossil #paleontology #theropod 2317
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 13/03/2026The tooth has distinct hourglass-shaped cross-section commonly seen in Nanotyrannus which may indicate that it actually came from the Hell Creek or Lance Formation. Or, it could be an undescribed Campanian nanotyrannid. It could also just be Gorgosaurus, possibly even some kind of teratophonein. 030
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 13/03/2026A worn dinosaur tooth of an indeterminate tyrannosaur, supposedly from the Judith River Formation in Montana, USA. Unfortunately, the provenance for this tooth is absent other than Northern Montana. #FossilFriday #dinosaur #fossil #paleontology #gorgosaurus #daspletosaurus #tyrannosaurid #theropod 1112
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 06/03/2026A dinosaur tooth of a cf. Afrovenator abakensis from the Irhazer Group in Marandet, Aderbissinat, Agadez, Niger. The cookies 'n cream colors can be quite pretty, albeit, the tooth is still fractured like most. #FossilFriday #dinosaur #fossil #paleontology #afrovenator #megalosaurid #theropod 061
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 27/02/2026A magnified view of the serrations or denticles. I'm not sure if the weakly developed serrations of the premax teeth point towards a more basal taxon like the albertosaurine Gorgosaurus, assuming the more derived tyrannosaurines like Daspletosaurus are more developed like in Tarbosaurus. 130
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 27/02/2026A dinosaur tooth of an indeterminate tyrannosaurid from the Judith River Formation in Valley County, Montana, USA. The serrations are oddly weakly developed, though it's unclear what that implies. #FossilFriday #dinosaur #fossil #paleontology #gorgosaurus #daspletosaurus #tyrannosaurid #theropod 2252
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 20/02/2026A fossilized partial placoderm head shield from a Bothriolepis canadensis from the Escuminac Formation in Escuminac Bay, Quebec, Canada. Bothriolepis was a highly prolific Devonian aged genus of armored fish found across the world. #FossilFriday #fish #placoderm #fossil #paleontology #bothriolepis 070
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 06/02/2026A pair of fragmentary fossilized teeth of a giant beaver or Castoroides dilophidus from Columbia County, Florida, USA. This extinct beaver genus lived alongside American beavers that are still around today. #FossilFriday #synapsid #mammal #fossil #paleontology #castoroides #beaver #rodent 0111
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 04/02/2026Are you referring to the procumbent premaxillary teeth? Saitta and Longrich 2024 do point that out as an autapomorphy of Nanotyrannus not see in any other tyrannosauroid. However, Napoli did state he did not find it a convincing character in the livestream he did on their Skeleton Crew channel. 010
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 30/01/2026Three indeterminate crocodylomorph teeth from the Csehbánya Formation in Veszprém County, Hungary. The teeth possibly belong to either cf. Allodaposuchus sp. or cf. Theriosuchus sp. #FossilFriday #crocodylomorph #fossil #paleontology #allodaposuchus #theriosuchus 061
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 23/01/2026A dinosaur tooth of an indeterminate sauropod, likely a titanosauriform from the Irhazer Group in the Agadez Region of Niger. I'm not entirely sure what it is, but the robust torpedo shaped morphology would suggest a macronarian of some kind. #FossilFriday #dinosaur #fossil #paleontology #sauropod 1202
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 16/01/2026While the two main tyrannosaurids described from this deposit are Gorgosaurus and Daspletosaurus, there may potentially be a Teratophoneini indet. and Tyrannosaurini indet. (cf. Tyrannosaurus sp.) also present in the Two Medicine Formation. 020
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 16/01/2026A partial dinosaur tooth of an indeterminate tyrannosaurid from the Two Medicine Formation in Pondera County, Montana, United States. Unfortunately, the mesial carinae is completely worn down. #FossilFriday #dinosaur #fossil #paleontology #gorgosaurus #daspletosaurus #tyrannosaurid #theropod 2273
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 10/01/2026The recent description of Xenovenator espinosai by Rivera-Sylva et al. suggests Albertavenator is a derived close relative, forming the clade Troodontini with the Troodon-type troodontids. So it is probably likely that Albertavenator did have these classic cf. Troodon teeth. www.mdpi.com/3674690mdpi.com 010
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 09/01/2026A fossilized lungfish of a Dipterus valenciennesi from the Achanarras Limestone Member, Old Red Sandstone at the Achanarras Quarry in Caithness, Scotland. These basal lungfish are found in various Devonian-aged deposits in Europe. #FossilFriday #fish #lungfish #fossil #paleontology #dipterus 0398
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 26/12/2025A fossilized bird jaw of a Dasornis sp. from Oued Zem, Khouribga, Morocco. Pelagornithids like the Eocene aged Dasornis are known as false-toothed or pseudotooth birds for their serrated beaks. #FossilFriday #dinosaur #bird #fossil #paleontology #dasornis #theropod 072
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 20/12/2025A close up view of the skull. More often, many of the fish specimens from Caithness are just a disarticulated mess of scales, so a fairly complete specimen is quite uncommon. 031
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 20/12/2025A fossilized lobe-finned fish of an Osteolepis panderi from the Old Red Sandstone near Skinnet Farm, Hill of Forrs, Thurso, Caithness, Scotland. Osteolepidids are more closely related to tetrapods and lungfish than to ray-finned fish. #FossilFriday #fish #fossil #paleontology #osteolepis 182
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 12/12/2025A close up view of an armor section. Most material found from this famous extinct millipede is in the form of these isolated, but distinct, armor pieces. 020
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 12/12/2025A fossilized armored millipede segment of an Arthropleura sp. from the Orzeskie Beds, Upper Silesia Coal Basin, Poland. These giant Carboniferous aged myriapods grew over two meters. The fern genus Zeilleria can also be seen on the slab. #FossilFriday #myriapod #fossil #paleontology #arthropleura 175
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 05/12/2025A magnified view of the serrations. The hook-shaped denticles on the distal carinae is a distinct characteristic that distinguishes these saurornitholestines from the contemporary dromaeosaurid, Dromaeosaurus albertensis, as well as young tyrannosaurs individuals of Gorgosaurus or Daspletosaurus. 040
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 05/12/2025A dinosaur tooth of an indeterminate saurornitholestine dromaeosaurid, possibly Saurornitholestes langstoni or Bambiraptor feinbergi from the Judith River Formation in Fergus County, Montana, USA. #FossilFriday #dinosaur #fossil #paleontology #saurornitholestes #bambiraptor #dromaeosaurid #theropod 1154
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 28/11/2025A mosasaur tooth of an indeterminate prognathodontin, possibly cf. Thalassotitan sp. from the Peedee Formation in Holden Beach, North Carolina, USA. This robust tooth morph is comparable to Thalassotitan atrox from Morocco. #FossilFriday #mosasaur #fossil #paleontology #thalassotitan #prognathodon 0112
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 21/11/2025A magnified view of the crown showing the worn, but present serrations on the carinae. While we don't have any today, land crocs seem to show up independently, and quite frequently, throughout crocodylomorph evolution. 050
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 21/11/2025A fossilized crocodylomorph tooth of an Doratodon carcharidens from the Csehbánya Formation in Veszprém County, Hungary. This Cretaceous aged terrestrial ziphosuchian croc had serrated teeth similar to those of theropod dinosaurs. #FossilFriday #crocodylomorph #fossil #paleontology #doratodon 171
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 15/11/2025In hindsight, this could have gone very poorly. So uh, always have a friend to help carry heavy objects. If sci-fi multiverse, alternate timeline stuff or whatever is real, then I'm sure there are instances where I did get fatally crushed by the Eubrontes after tumbling down stairs. 030
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 15/11/2025A minor correction, apparently this slab of rock is around 78 pounds according to the UPS label. That's what I thought as first, but assumed it was lighter once I managed to carry it up the stairs, but I guess I can carry close to 80 pounds. I only weigh a bit over 100 pounds, so that's surprising. 130
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 15/11/2025This 11-12 inch Eubrontes weights about 50-60 pounds which made it quite dangerous to carry up stairs. Eubrontes and other similar morphologies have sometimes been attributed to basal sauropodomorphs as well, but they are generally assumed to be Dilophosaurus-sized theropods in affinity. 163
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 15/11/2025A dinosaur footprint of the ichnotaxon Eubrontes giganteus from the East Berlin Formation in Connecticut, USA. This Jurassic aged ichnogenus is possibly from Dilophosaurus or a similar species. #FossilFriday #dinosaur #fossil #ichnology #paleontology #eubrontes #gigandipus #dilophosaurus #theropod 181
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 07/11/2025A magnified view of the crown, albeit very worn, showing the molar-like morphology of the tooth. This is one of the weirdest archosaur teeth around as most herbivorous species tend to develop leaf-shaped teeth than the mammalian style dentition seen in Iharkutosuchus. 051
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 07/11/2025A fossilized crocodylomorph tooth of an Iharkutosuchus makadii from the Csehbánya Formation in Veszprém County, Hungary. Unlike the leaf-shaped teeth of herbivorous crocs like Simosuchus, this genus evolved mammal-like dentition. #FossilFriday #crocodylomorph #fossil #paleontology #iharkutosuchus 161
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 31/10/2025I'm not sure what this means for unserrated tyrannosaur premaxillary teeth from older deposits like the Judith River or Two Medicine Formation. Do they represent an undescribed Nanotyrannidae indet., or at least, a more basal eutyrannosaur/pantyrannosaur of some kind? www.nature.com/articles/s41...nature.comNanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous - NatureNature - Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous 040
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 31/10/2025While unserrated premaxillary teeth were supposedly an ontogenetically variable character, proposed to be found in young Gorgosaurus, recent studies on Nanotyrannus by Zanno and Napoli 2025 have shown this may not be the case. Which may mean they belong to Nanotyrannus lancensis and N. lethaeus. 190
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 31/10/2025A rooted dinosaur tooth of a Nanotyrannus sp. from the Hell Creek Formation in Carter County, Montana, USA. This unserrated basal morphology was previously known as the tooth taxon, Aublysodon amplus. #FossilFriday #dinosaur #fossil #paleontology #aublysodon #nanotyrannus #tyrannosaurid #theropod 2102
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 30/10/2025Comparison with what I believe is a true juvenile young Tyrannosaurus rex (right). While tyrannosaur teeth are very similar to one another, Nanotyrannus teeth are distinguished from T. rex by the hourglass (or figure eight) shape of the cross-section opposed to being oval or round in tyrannosaurins. 020
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 30/10/2025A dinosaur tooth of a Nanotyrannus sp. from the Hell Creek Formation in Carter County, Montana, USA. This nanotyrannid eutyrannosaur has two species, N. lancensis and N. lethaeus. Welcome back Nanotyrannus. For good this time. #dinosaur #fossil #paleontology #nanotyrannus #tyrannosaurid #theropod 130
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 24/10/2025A magnified view of the serrations, as well as defined ridges down the crown. Hungarosaurus's close relative, Struthiosaurus, could potentially be found here as well which will likely make distinguishing isolated teeth difficult, if not impossible. They are both struthiosaurin nodosaurids after all. 020
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 24/10/2025A dinosaur tooth of an ankylosaur, either Hungarosaurus tormai or cf. Struthiosaurus sp. from the Csehbánya Formation in Veszprém County, Hungary. Hungarosaurus is known for its long forelimbs. #FossilFriday #dinosaur #fossil #paleontology #hungarosaurus #struthiosaurus #ankylosaur #ornithischian 172
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 17/10/2025A magnified view of the bone showing what may or may not be bite marks from a predator. Some of the theropods that may have hunted Dzharacursor include the tyrannosaur, Timurlengia, the carnosaur (or carcharodontosaurian) Ulughbegsaurus, and the large dromaeosaurid, Itemirus. 041
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 17/10/2025A partial fossilized metatarsal of a theropod, possibly Dzharacursor bissektensis from the Bissekty Formation in Dzharakuduk, Kyzylkum Desert, Uzbekistan. This species was previously referred to Archaeornithomimus. #FossilFriday #dinosaur #fossil #paleontology #dzharacursor #ornithomimid #theropod 1101
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 10/10/2025A fossilized osteoderm from a Cretaceous aged softshelled turtle, possibly Khunnuchelys kizylkumensis from the Bissekty Formation in Dzharakuduk, Kyzylkum Desert, Uzbekistan. Other species of this genus also occur in China and Kazakhstan. #FossilFriday #turtle #fossil #paleontology #khunnuchelys 1155
Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 04/10/2025Today is the 120th anniversary of the description of #Tyrannosaurus rex and #Albertosaurus sarcophagus in 1905 by Henry Fairfield Osborn, the two species that would define the clade, Tyrannosauridae. A pair of dinosaur teeth, albeit very worn, belonging to these two famous species. 🧪 0215