ThePhysicist Posted October 18, 2023 Share Posted October 18, 2023 (edited) Hi y'all, I came across this odd lower mammal molar from the HCF and I still can't make a more precise determination. It doesn't seem to follow the metatherian tooth design, so I guessed it must be eutherian. It seems to have only four cusps. Any insight is appreciated, and I can provide more photos if need be. @jpc Edit: I can't seem to tag people, could someone page jpc? Edited October 18, 2023 by ThePhysicist 1 Forever a student of Nature Link to comment Share on other sites More sharing options...
Coco Posted October 18, 2023 Share Posted October 18, 2023 @jpc Coco ---------------------- OUTIL POUR MESURER VOS FOSSILES : ici Pareidolia : here Ma bibliothèque PDF 1 (Poissons et sélaciens récents & fossiles) : ici Ma bibliothèque PDF 2 (Animaux vivants - sans poissons ni sélaciens) : ici Mâchoires sélaciennes récentes : ici Hétérodontiques et sélaciens : ici Oeufs sélaciens récents : ici Otolithes de poissons récents ! ici Un Greg... Link to comment Share on other sites More sharing options...
jpc Posted October 18, 2023 Share Posted October 18, 2023 (edited) Here I am. Referring to your last photo, there is fifth cusp on the talonid (the lower half of the tooth seen in the left half of said photo. Where your blue line bends along the bottom edge close to the leftmost cusp. This is a a marsupial (metatherian) characteristic. On the other hand, there are only two cusps on the taller part (the trigonid), and that is confusing and non-marsupialian. So, I stand with you... uncertainty rules. I only checked Lillegraven's Mesozoic mammals book. there are other sources out there to look at. Edited October 18, 2023 by jpc 1 Link to comment Share on other sites More sharing options...
ThePhysicist Posted October 19, 2023 Author Share Posted October 19, 2023 9 hours ago, jpc said: Referring to your last photo, there is fifth cusp on the talonid (the lower half of the tooth seen in the left half of said photo. Where your blue line bends along the bottom edge close to the leftmost cusp. Okay, I saw that but it's so subdued I didn't consider it one. Here are some more photos, not that it helps the ID: 9 hours ago, jpc said: On the other hand, there are only two cusps on the taller part (the trigonid), and that is confusing and non-marsupialian. So, I stand with you... uncertainty rules. I only checked Lillegraven's Mesozoic mammals book. there are other sources out there to look at. Thanks for your input, ya two cusps on the trigonid is odd, it's not broken and doesn't appear pathological? I've so far referenced the publications below, and yet to see something resembling it. I think I'll reach out to a few other professionals to see if it's interesting. * Clemens, William A. Fossil Mammals of the Type Lance Formation, Wyoming. Part II, Marsupialia. University of California Press, 1966. * Kielan-Jaworowska, Zofia, et al. Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure, Columbia University Press, 2004. * Wilson Mantilla GP et al. 2021 Earliest Palaeocene purgatoriids and the initial radiation of stem primates. R. Soc. Open Sci. 8: 210050. https://doi.org/10.1098/rsos.210050 * Richard C. Fox. 2015. A revision of the Late Cretaceous–Paleocene eutherian mammal Cimolestes Marsh, 1889. Canadian Journal of Earth Sciences. 52(12): 1137-1149. https://doi.org/10.1139/cjes-2015-0113 18 hours ago, Coco said: @jpc Coco I also can't react to posts, thank you! Forever a student of Nature Link to comment Share on other sites More sharing options...
ThePhysicist Posted November 13, 2023 Author Share Posted November 13, 2023 On 10/18/2023 at 8:49 AM, jpc said: Here I am. Referring to your last photo, there is fifth cusp on the talonid (the lower half of the tooth seen in the left half of said photo. Where your blue line bends along the bottom edge close to the leftmost cusp. This is a a marsupial (metatherian) characteristic. On the other hand, there are only two cusps on the taller part (the trigonid), and that is confusing and non-marsupialian. So, I stand with you... uncertainty rules. I only checked Lillegraven's Mesozoic mammals book. there are other sources out there to look at. I just checked Lillegraven 1969 (linked), and I think it's a dead ringer for Gypsonictops P4: Looks like a pretty interesting phylogeny, being an early eutherian with potential relation to insectivores, rodents, and primates! 2 Forever a student of Nature Link to comment Share on other sites More sharing options...
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