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Found 9 results

  1. To pass some time I've been recently researching early Paleocene life and I keep coming back to researching (in my view) the two strangest and controversial Late Cretaceous-Early Paleocene Formations I know of. These are the Hornerstown Formation dating 66.5-65.5 Million Years ago in what is now New Jersey, U.S. And the Takatika Grit Formation dating 66.5-60.0 Million Years ago in what is now the Chatham Islands, New Zealand. https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0b3baee9ab1afc7973337f5047495b723fcfa4f2 https://www.researchgate.net/publication/315461615_The_age_of_the_Takatika_Grit_Chatham_Islands_New_Zealand https://www.sciencedirect.com/science/article/abs/pii/S0195667109000184?via%3Dihub I've read many reports about these formations and the pretty controversial stuff that's been found in both these areas (Paleocene ammonites and reports of archaic marine reptiles like Paleocene Mosasaurs). I'm really not 100% sure what to make of this as I've heard conflicting hypotheses on whether these more archaic marine reptile fossils were reworked from older formations while others say it's not too too likely? https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/maastrichtian-ammonites-from-the-hornerstown-formation-in-new-jersey/4F051D07668B7B893EEFECF0506E2F1B https://bioone.org/journals/acta-palaeontologica-polonica/volume-57/issue-4/app.2011.0068/Short-Term-Survival-of-Ammonites-in-New-Jersey-After-the/10.4202/app.2011.0068.full For most of these "controversial" specimens, I would say reworking is likely while some I'll admit I'm not sure? For the Mosasaurs, it's clear that the astroid impact 66 Million Years ago caused their total extinction, but I'm still not 100% convinced that none emerged from the event alive (at least barely) and swam the seas in the very first days of the Danian Paleocene but not too long after. Unlike the mostly terrestrial Non-Avian Dinosaurs, which could only hide in so many places and it's very unlike more than a tiny amount of individuals (not enough to support a population) made it into the Paleocene, the Oceans have slightly more areas to hide and more even for endothermic air breathing animals like Mosasaurs (though as an endotherm, food does become a major issue especially when the ocean food chain nearly collapsed completely). What I'm wondering is how valid are at least "some" of these supposed archaic marine reptile and ammonite fossils from the earliest Paleocene sections of the Hornerstown Formation and the Takatika Grit? Also, of all the Maastrichtian Mosasaurs known so far, which ones would have been the mostly likely to have (at least briefly) survived the Cretaceous-Paleocene Extinction Event of 66 Million Years ago (would it have been generalist feeders, ones that specialized in deep sea hunting, ones with cosmopolitan distributions, ones small by mosasaur standards but still around the same size of the few confirmed large reptiles that survived the event like the 8 meter (26 feet) in length Thoracosaurus, or ones with all these traits and advantages)?
  2. Yesterday I was in South Limburg, the Netherlands, for an appointment. And after a journey of almost 3 hours, my appointment was canceled due to a sudden toothache. Well nothing can be done about it, all understandable, and with the sun-drenched afternoon ahead I wanted to make the best of it. Armed with only a pair of boots, a pocket knife and Google maps, I went looking for possible fossil hotspots. I'm glad I always have something in the car, for such "emergencies". Of course with respect for nature and the beautiful limestone walls that South Limburg has to offer, I went looking around Maastricht and the Belgium border area! There are still plenty of opportunities to find fossils, especially around abandoned cave entrances. Many rocks are crumbling and around small cave entrances there are sometimes beautiful pieces of limestone and flint that have fallen from the rocks due to erosion. I decided to drive around looking for such places. In any case, it provided beautiful views of the landscape. Around Maastricht I found some deserted limestone walls where I tried my luck. Sometimes quite exciting, although I do not enter the caves (safety comes first!), there is sometimes a somewhat strange atmosphere. People have clearly slept in the area where I was looking, in one of the caves there was an abandoned mattress and there are some empty looks of someone who had clearly made it his home. Walking a bit further along the road I found large and small pieces of limestone which probably came down in the past period together with pieces of flint. Quickly collected some pieces to further investigate (at a distance from the wall) for fossils. I found several nice pieces within an hour. Especially a lot of small Belemnitella, mostly broken, but some still presentable. Pair of very small Bivalves and to top it off a small shark tooth. I had to take a closer look, but a spot search in the database of Paleontica gave me the name Centrophoroides appendiculatus. Here are some pictures that give an impression of my finds. Not yet well prepared, fresh from the often damp limestone. This is how the day became successful and I am once again richer in shark species from the Limburg Cretaceous. It was very nice to see many shells and flint in limestone walls again, as if caught in time. I brought another bucket with some loose pieces to further explore at home, so who knows what I will find .
  3. Joseph Fossil

    The Missouri Tyrannosaur

    In a previous post, I discussed if Tyrannosaurus rex (Tyrannosaur, Western North America) (Late Cretaceous 68-66 Million Years ago) was able to colonize Eastern North America as the Western Interior Seaway retreat by the early Maastrichtian (I received excellent feedback from other four members, notably @Troodon, that this was prevented by the KT Mass Extinction event 66 Million Years ago). As a result, I don't believe Tyrannosaurus rex was able to effectively colonize Eastern North America (as far as I'm currently aware). However, looking over some records of Late Cretaceous Tyrannosaur fossils, I do believe that a Tyrannosaurid (Yes a Tyrannosaurid) was able to colonize part of Eastern North America in the area of what is today Chronister well, Bollinger County, Missouri! Not much is known about this Tyrannosaur genera, but here is the info I could find on it! Unnamed Tyrannosauroidea genus (Tyrannosaur) (McNair Sand Member of the Ripley Formation-Missouri, US, North America) (Late Cretaceous, 70-66 Million Years ago) (Size unknown) http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&taxon_no=38606&max_interval=Cretaceous&country=United States&state=Missouri&is_real_user=1&basic=yes&type=view&match_subgenera=1 https://www.lakeneosho.org/Ozarks/Chronister2.html https://www.sos.mo.gov/CMSImages/Publications/symbols/dinosauressay.pdf Photographs of the Chonister well Tyrannosaur specimens have also been tricky to find, the only ones I've found were shown during an August 2016 Science in St. Louis Seminar series lecture by Geologist Dr. Micheal Fix, Ph.D., Associate Teaching Professor, Department of Physics of University of Missouri-St.Louis titled Monster in the Hollow: The Story of Missouri's Ozark Dinosaurs. The presentation also showed a photograph of a decent sized Dromeaosaurid tooth from the same site in Missouri!
  4. Jurassicbro238

    Help on ID for Lance Formation Fossils

    Hello, I've got some fossils from Niobrara County, Wyoming in the Lance Formation that need some ID if its possible. The scale bar is in inches (top) and centimeters (bottom). Thank you for your time. #1 I'm confident is a skull piece but I was wondering if anyone knew what bone or perhaps what group of animals it belongs to? I see a hole on the inner side that was most likely a passage for a vein, and there are smaller holes on the outside as well. I'm hoping it's identifiable because one of the edges is not broken and is natural. #2 At first I thought was warped gar scale. After cleaning it however, I found that it seems to have an articulation point on the end. I haven't seen any gar scales like that and I'm wondering if it's another fish I'm not aware of. Or maybe its not a scale at all?
  5. 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)
  6. roxanneminerals

    Austin Chalk Mosasaur Fossil ??

    I found this rock in Austin, TX in Waller Creek next to an exposed outcrop of the Maastrichtian (Late Cretaceous) Austin Chalk. I’m wondering if it’s a mosasaur vertebra or humerus? Several mosasaurs have been found in creeks nearby, and the wavy pattern in the rock reminds me of fossilized bone. I’ve included three photos of the rock that I found in Austin, and a photo from Otero et al. (2016) of a Maastrichtian mosasaur right humerus (scale bar = 50 mm) that looks similar.
  7. Crankyjob21

    BBB2BB6B-9E88-4B73-B15C-7581DC900234

    From the album: Cranky’s album of fossils

    A tooth belonging to the Mosasaur prongnathodon Giganteaus
  8. I_gotta_rock

    Shell Made its Own Pedistal

    From the album: Delaware Fossils

    A Gryphea vomer bivalve made itself at home atop the internal mold of a tiny Baculites ovatus cephalopod. The whole thing is about 3 cm tall. Found in the Cretaceous spoils sands of the C&D Canal, Delaware
  9. Sinopaleus

    Sphenodiscus lenticularis

    Sphenodiscus lenticularis Late Cretaceous (Maastrichian) Fox Hills Formation, South Dakota, U.S.A
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