Ben Creisler
Some new papersÂwith free pdfs in Research Gate:
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After description of the first known footprint attributed to Tyrannosaurus rex by Lockley and Hunt in 1994, the lead author (TC) began a systematic search for more tracks of this giant theropod in the Raton Basin. During parts of eight field seasons in the mid and late 1990s and early 2000s, two finds were made and interpreted to be tracks of large tyrannosaurids very similar in size to the one that made the original footprint. The material, which is preserved as convex hyporelief, consists of a tridactyl right pes print lacking a hallux impression coming from a locality near Ludlow, Colorado, and a track array, here interpreted as a convex hyporelief left pes print with a single toe impression, likely that of a hallux, and a pair of parallel convex hyporelief forearm prints with partial hand impressions from Cimarron, New Mexico. Near the track array an "L"-shaped impression in convex hyporelief is interpreted to have been the impression of carrion or a prey item. Like the original material of Tyrannosauripus pillmorei, these traces are present in the Upper Cretaceous lower coal zone of the Raton Formation. The track array is hypothesized to have been made by a prone adult T. rex, rising from a quadrupedal position. In standing up, the dinosaur stepped forward and made the left pes print, while at nearly the same time it made the forearm prints as it pushed down with its forearms and wrists to facilitate its rise to a standing, walking, or running posture.
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An isolated anterior left dentary, proximal caudal centrum and an isolated right femur pertaining to adult, subadult and juvenile tyrannosaurid dinosaurs from the Upper Cretaceous deposits of the San Juan Basin in New Mexico preserve several bite marks and other feeding traces made by another tyrannosaurid. The dentary was recovered from the Ne-nah-ne-zad Member of the Fruitland Formation (Campanian); whereas, the femur was recovered from De-na-zin Member of the Kirtland Formation (Campanian), and the isolated caudal centrum was recovered from the Naashoibito Member of the Ojo Alamo Formation (Maastrichtian). The presence of bone surface healing around the bite marks in the dentary indicate that the biting occurred pre-mortem; whereas, the absence of bone surface healing around the bite marks in the caudal centrum and the right femur indicates the biting most likely took place post-mortem. Intensely tooth-marked bones clearly show that the San Juan Basin tyrannosaurids attacked and fed upon the remains of not only their most common prey such as ceratopsians, hadrosaurs, and sauropods, but also conspecifics. The bite marks described here represent four categories: bite-and-drag, drag-and-scrape, puncture, and puncture-and-collapse. The specimens provide new evidence for cannibalism among tyrannosaurids. Although extensively tooth marked, these bones do not support the previous assumptions of selective feeding behavior of these iconic predators based on inferred bite marks.
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Martin Lockley, Brent Breithaupt, Neffra A. Matthews, Kenichiro Shibata & ReBecca Hunt-Foster (2021)
A preliminary report report on an Early Jurassic Eubrontes-dominated tracksite in the Navajo Sandstone Formation at the Mail Station dinosaur tracksite, San Juan County, Utah.
In: Lucas, S. G., Hunt, A. P. & Lichtig, A. J., 2021, Fossil Record 7. New Mexico Museum of Natural History and Science Bulletin 82: 195-208
https://www.researchgate.net/publication/340639035_A_LOWER_JURASSIC_EUBRONTES-DOMINATED_TRACKSITE_IN_THE_NAVAJO_FORMATIONEASTERN_UTAH_PROPOSED_PROTOCOLS_FOR_UNRAVELLING_TRACKSITE_HISTORYThe Mail Station Dinosaur Tracksite (MSDT), situated on Bureau of Land Management land in San Juan County, Utah, is one of the largest and best-preserved Lower Jurassic dinosaur tracksites in the western USA. The site is located stratigraphically near the top of the Navajo Sandstone Formation (Glen Canyon Group) and is dominated by large theropod tracks referable to the ichnogenus Eubrontes. The cartography of the site reveals at least 100 mostly well-preserved tracks representing at least 24 trackways with highly variable orientations. At least four trackways provide evidence of running individuals attaining estimated speeds of up to ~49 km/hour, which is the fastest estimated speed for any known Jurassic theropod. The MSDT is one of about 130 that have yielded Eubrontes or Eubrontes-like tracks in the Glen Canyon Group of the western USA. Of these, only a minority have yielded maps with multiple trackways and very few have yielded trackways with the well-preserved tracks (preservation grade 3) found at the MSDT. To date, none of the known Eubrontes sites from the Glen Canyon Group have yielded track morphologies that have been identified at the ichnospecies level. At MSDT it is possible to distinguish an earlier phase of trackmaking in which poorly preserved small tracks were overprinted during a second phase of trackmaking by large Eubrontes trackmakers. Further study is necessary to determine if additional phases of tracksite history can be unraveled.
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Also (link was accidentally posted yesterday for a different article, since corrected):
The early discoveries of Jurassic vertebrate remains in the Vaches Noires (Normandy, France). - This article traces the history of vertebrate paleontology, before the 1850s, in the Jurassic of the Vaches Noires, between Dives-sur-Mer and Villers-sur-Mer. It highlights the role of 18th century natural history cabinets and the collections of some learned amateurs in the early 19th century. Among the personalities who contributed to the history of these discoveries, Charles Bacheley (1716-1795) was a pioneer. Although Georges Cuvier made famous his collection of reptile bones from the Vaches Noires, Bacheley remained unknown to historians of sciences for a long time. This abbot from the Pays dâAuge evoked as early as 1778 the possibility that these remains may have belonged to animals with no living analogues. He was above all the first one in France to discover dinosaur remains. This article also presents the contribution of another fossil collector, FÃlix de Roissy (1771-1843). The family history of this Parisian aristocrat, who was a keen palaeontologist, was closely linked to the castle of Villers-sur-Mer. His frequent stays in this locality enabled him to acquire important specimens, which were studied by his friend Henri Marie Ducrotay de Blainville and later by Jacques-Amand and EugÃne Eudes-Deslongchamps. Finally, the role of Pierre Tesson (1797-1874) is highlighted. He was considered in his time to be one of the greatest collectors of fossils in Normandy. The sale of his collection to the British Museum in London was regarded as a considerable loss by the Norman scientific community. In retrospect, this transfer across the Channel enabled the Tesson collection to be saved when it is known that the palaeontological collections kept in Caen were destroyed during World War II.
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