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32-523: Traditionally, the Kaiparowits Formation has been considered to be roughly equivalent in age to the northern Dinosaur Park Formation . This, combined with the differences in fauna between the two formations, has led some scientists, most notably Scott Sampson, to conclude that there was some barrier separating northern and southern Laramidia at this time. However, preliminary re-calibration of late Cretaceous formation correlations suggests that

64-524: A UNESCO World Heritage Site where the formation is well exposed in the badlands that flank the Red Deer River . The Dinosaur Park Formation is composed of sediments that were derived from the erosion of the mountains to the west. It was deposited on an alluvial to coastal plain by river systems that flowed eastward and southeastward to the Bearpaw Sea, a large inland sea that was part of

96-460: A carapace covered with raised, flattened tubercles , which are not seen in any other turtle. This allows even small shell fragments to be identified as Compsemys . The skull resembles that of the alligator turtle , with a sharply hooked beak; Compsemys must have been an aquatic carnivore . The oldest known shell fragments identifiable as Compsemys are known from the Santonian stage of

128-674: A partial skeleton Dinosaur Park Formation The Dinosaur Park Formation is the uppermost member of the Belly River Group (also known as the Judith River Group ), a major geologic unit in southern Alberta . It was deposited during the Campanian stage of the Late Cretaceous , between about 76.5 and 74.4 million years ago. It was deposited in alluvial and coastal plain environments, and it

160-535: A recent analysis by Herrero and Farke. Boremys B. grandis A baenid Arvinachelys A. goldeni A baenid, notable for its atypical nasal structure. Denazinemys D. nodosoa middle unit of the upper Kaiparowits Formation A baenid Neurankylus Two species A baenid Thescelus int. A baenid Compsemys C. victa A paracryptodiran Adocus indet., possibly several species An adocid Basilemys B. nobilis A possible member of Nanhsiungchelyidae . By far

192-475: A single day. The most common remains of young hadrosaurs in the Dinosaur Park Formation are dentaries , bones from limbs and feet, as well as vertebral centra . The material showed little or none of the abrasion that would have resulted from transport, meaning the fossils were buried near their point of origin. Bonebeds 23, 28, 47, and 50 are productive sources of young hadrosaur remains in

224-590: A species of Stegoceras [REDACTED] Gravitholus G. albertae "Frontoparietal dome." Potentially synonymous with Stegoceras validum . Hanssuesia H. sternbergi Lower, also present in the Oldman Formation and Judith River Formation Potentially synonymous with Stegoceras validum . Sphaerotholus S. lyonsi Upper, 76.10 ± 0.5 Ma Right squamosal Stegoceras S. validum Specimens including frontoparietal dome. " Microcephale " A nomen nudum . In

256-477: A variety of early mammals including multituberculates , marsupials , and insectivorans . Recent finds include large specimens of the duckbill Gryposaurus , including the species G. monumentensis , and the first described remains of the oviraptorosaurian Hagryphus giganteus . Trace fossils are also known from the Kaiparowits, including an excellently preserved hadrosaur skin impression known from

288-665: Is an extinct genus of prehistoric turtles from the Late Cretaceous and Paleocene of North America and possibly Europe. The type species C. victa , first described by Joseph Leidy from the Hell Creek Formation in Montana in 1856, and another probable species C. russelli (originally placed in the separate genus Berruchelus ), described in 2012, from Paleocene deposits in France . Its affinites have long been uncertain, but it has recently been considered to be

320-468: Is bounded by the nonmarine Oldman Formation below it and the marine Bearpaw Formation above it. The Dinosaur Park Formation contains dense concentrations of dinosaur skeletons, both articulated and disarticulated, which are often found with preserved remains of soft tissues. Remains of other animals such as fish , turtles , and crocodilians , as well as plant remains, are also abundant. The formation has been named after Dinosaur Provincial Park ,

352-439: Is known from skull bones and a partial juvenile skeleton. Caimanine Known from a lower jaw fragment. Is the oldest known true caiman found. Deinosuchus A very large alligatoroid, almost or over 10 meters in length. A very large alligatoroid, similar in size to D. hatcheri . Goniopholid A new genus that exceeded 3 meters in length. Has a thin snout suited for piscivory. Leidyosuchus A new species known from

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384-473: Is not a coincidence as the invertebrate shells would have slowly dissolved and released enough basic calcium carbonate to protect the eggshells from naturally occurring acids that otherwise would have dissolved them and prevented fossilization. In contrast with eggshell fossils, the remains of very young hadrosaurs are actually somewhat common. Darren Tanke has observed that an experienced collector could actually discover multiple juvenile hadrosaur specimens in

416-602: The Western Interior Seaway . That sea gradually inundated the adjacent coastal plain, depositing the marine shales of the Bearpaw Formation on top of the Dinosaur Park Formation. The Dinosaur Park Formation is about 70 metres (230 ft) thick at Dinosaur Park. The lower portion of the formation was laid down in fluvial channel environments and consists primarily of fine- to medium-grained, crossbedded sandstones . The upper portion, which

448-412: The Western Interior Seaway . The jungle theory would also support why almost all the animals in the Kaiparowits Formation were new species, and why the deposits were so plentiful. Without the need for herbivores to migrate to find food, and theropods to migrate after herbivores, a whole ecosystem could evolve secluded from interbreeding. The theory also supported why the dinosaurs adorned such features like

480-426: The 15 horns of Kosmoceratops , they were for sexual selection . Animals present include chondrichthyans (sharks and rays), gars , bowfin , sturgeons , frogs , salamanders , turtles , lizards , crocodilians (including Deinosuchus ), coelurosaurian theropods such as dromaeosaurids , troodontids , and Ornithomimus velox , armored dinosaurs , the duckbill Parasaurolophus cyrtocristatus , and

512-416: The Dinosaur Park Formation, small theropods are rare due to the tendency of their thin-walled bones to be broken or poorly preserved. Small bones of small theropods that were preyed upon by larger ones may have been swallowed whole and digested. In this context, the discovery of a small theropod dinosaur with preserved tooth marks was especially valuable. Possible indeterminate avimimid remains are known from

544-461: The Kaiparowits Formation dates from about 77.24 to 75.02 million years ago, with the volcaniclastic Upper Valley Member estimated to date from 73.8 to 72.8 million years ago. The timeline below follows the re-calibrated timeline of Fowler (2017), showing species from the Kaiparowits Formation in green, and related species from Alberta in blue. The Kaiparowits Formation is a muddy bed that was deposited between about 77.3 to 72.8 million years ago, in

576-503: The area where the Grand Staircase–Escalante National Monument of Utah is today. It is extremely fossil rich, with thousands of plants and animal fossils being preserved in amongst its sandstone and mudstone deposits. Based on plants remains including multiple vines, leaves, and branches, It was assumed by paleontologists Scott Sampson and his colleagues that Utah in the Campanian was a dense jungle bordering

608-410: The authors were unable to determine what specific factors shaped nesting ground choice in the formation's hadrosaurs. They suggested that behavior, diet, soil condition, and competition between dinosaur species all potentially influenced where hadrosaurs nested. Sub-centimeter fragments of pebbly-textured hadrosaur eggshell have been reported from the Dinosaur Park Formation. This eggshell is similar to

640-487: The following amphibians have been found in the formation: Albanerpetontidae (extinct, salamander -like amphibians) Caudata ( salamanders ) Salientia ( frogs ) Remains of the following dinosaurs have been found in the formation: Remains of the following ornithischians have been found in the formation: An unnamed Pachyrhinosaurus -like taxon has been recovered from the formation. At least one indeterminate thescelosaurid specimen has been recovered from

672-407: The formation is characterized by the abundance of Corythosaurus and Centrosaurus . This group of species is replaced higher in the formation by a different ornithischian fauna characterized by the presence of Lambeosaurus and Styracosaurus . The appearance of several new, rare species of ornithischian at the very top of the formation may indicate that a third distinct fauna had replaced

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704-485: The formation, especially bonebed 50. The bones of juvenile hadrosaurs and fossil eggshell fragments are not known to have preserved in association with each other, despite both being present in the formation. Foraminacephale F. brevis Also present in the Oldman Formation Frontoparetal dome, various other skull fragments including juvenile and subadult material Once thought to be

736-407: The formation. A new taxon of troodontid based solely on teeth is known from the upper part of the formation. Choristoderes , or champsosaurs , were aquatic reptiles. Small examples looked like lizards, while larger types were superficially similar to crocodilians. Remains of the following Choristoderes have been found in the formation: Remains of the following Crocodylians have been found in

768-418: The formation. In a 2001 review of hadrosaur eggshell and hatchling material from the Dinosaur Park Formation, Darren H. Tanke and M. K. Brett-Surman concluded that hadrosaurs nested in both the ancient upland and lowlands of the formation's depositional environment. The upland nesting grounds may have been preferred by the less common hadrosaurs, like Brachylophosaurus or Parasaurolophus . However,

800-408: The formation: Remains of the following lizards have been found in the formation: Remains of the following Plesiosaurs have been found in the formation: Remains of the following pterosaurs have been found in the formation: Remains of the following turtles have been found in the formation: Remains of the following mammals have been found in the formation: Compsemys Compsemys

832-515: The hadrosaur eggshell of Devil's Coulee in southern Alberta as well as that of the Two Medicine and Judith River Formations in Montana, United States. While present, dinosaur eggshell is very rare in the Dinosaur Park Formation and is only found in two different microfossil sites. These sites are distinguished by large numbers of pisidiid clams and other less common shelled invertebrates like unionid clams and snails. This association

864-458: The largest native turtle at about 78 centimeters in length. Helopanoplia indt. A softshell turtle Bernissartia May not be Bernissartia proper, but a close cousin. It would extend the family's time range to the Campanian. Alligatoroid Is similar in form to Allognathosuchus . Brachychampsa A new species yet to be described. Reached around 2 meters in length and

896-582: The most basal member of Paracryptodira , despite the clade first appearing in the Late Jurassic, and is sometimes included in its own family, Compsemydidae . A revision in 2020 found Compsemydidae to be more expansive, also containing Riodevemys and Selenemys from the Late Jurassic of Europe, and Peltochelys from the Early Cretaceous of Europe. Compsemys was a moderately sized turtle, up to 30 cm (12 in) long, with

928-568: The second during the transition into younger, non-Dinosaur Park sediments, at the same time an inland sea transgresses onto land, but there are fewer remains here. An unnamed pachyrhinosaur , Vagaceratops irvinensis , and Lambeosaurus magnicristatus may be more common in this third fauna. The timeline below follows a synthesis presented by Fowler (2017) with additional information from Arbour et al. 2009, Evans et al. 2009, and Penkalski, 2013. Megaherbivore Assemblage Zones (MAZ) follow data presented by Mallon et al. , 2012. Remains of

960-535: The underlying Oldman Formation and they were originally included in that formation. The two formations are separated by a regional disconformity , however, and are distinguished by petrographic and sedimentologic differences. In addition, articulated skeletal remains and bonebeds are rare in the Oldman Formation but abundant in the Dinosaur Park Formation. The Dinosaur Park Formation can be divided into at least two distinct faunas. The lower part of

992-485: The upper part of the Kaiparowits, where many of the unique species are found, is actually younger than the Dinosaur Park, and that some Kaiparowits species may simply be the descendants of Dinosaur Park species. However, new dates reveal that this is simply an artifact of inaccurate Ar-Ar dating , and both formations had similar ages. According to new Uranium-Lead stratigraphic data, the fossil-bearing portion of

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1024-413: Was deposited in overbank and floodplain environments, consists primarily of massive to laminated, organic-rich mudstones with abundant root traces, and thin beds of bentonite . The Lethbridge Coal Zone, which consists of several seams of low-rank coal interbedded with mudstones and siltstones , marks the top of the formation. The sediments of the Dinosaur Park Formation are similar to those of

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