|
Sundance Sea
The Sundance Sea was an epeiric sea that existed in North America during the mid-to-late Jurassic Period of the Mesozoic Era. It was an arm of what is now the Arctic Ocean, and extended through what is now western Canada into the central western United States. The sea receded when highlands to the west began to rise. Stratigraphy The Sundance Sea did not occur at a single time; geological evidence suggests that the Sea was actually a series of five successive marine transgressions—each separated by an erosional hiatus—which advanced and receded from the middle Jurassic onward. The terrestrial sediments of the Morrison Formation—eroded from rising highlands to the west—were deposited on top of the marine Sundance sediments as the sea regressed for the last time late in the Jurassic. Fauna The Sundance Sea was rich in many types of animals. ''Gryphaea'' was extremely common, and shark teeth have been found. In addition to fish, belemnites and to an extent ammonites ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epeiric Sea
An inland sea (also known as an epeiric sea or an epicontinental sea) is a continental body of water which is very large and is either completely surrounded by dry land or connected to an ocean by a river, strait, or "arm of the sea". An inland sea will generally have higher salinity than a freshwater lake, but usually lower salinity than the open ocean. Definition What constitutes an "inland sea" is complex and somewhat necessarily vague. The United States Hydrographic Office defined it as "a body of water nearly or completely surrounded by land, especially if very large or composed of salt water". Geologic engineers Heinrich Ries and Thomas L. Watson say an inland sea is merely a very large lake. Rydén, Migula, and Andersson and Deborah Sandler of the Environmental Law Institute add that an inland sea is "more or less" cut off from the ocean. It may be semi-enclosed, or connected to the ocean by a strait or "arm of the sea". An inland sea is distinguishable from a bay in that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoid
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths as great as . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shell, Wyoming
Shell is a census-designated place (CDP) in Big Horn County, Wyoming, United States. The population was 83 at the 2010 Census. The community is named for the abundance of fossil shells located in the area. Nearby exposed formations such as the Cloverly Formation and the Morrison Formation have yielded numerous fossils of dinosaurs and other animals. Located to the west of the town is the Red Gulch Dinosaur Tracksite, a rare collection of dinosaur tracks from the Jurassic period. Shell is home to the Iowa State University geology field station. Geography According to the United States Census Bureau, in 2010 the CDP has a total area of 1.1 square miles (2.96 km), all land. Shell is located at the base of the Big Horn Mountains, at the mouth of Shell Canyon. Nearby Shell Creek rises in the Big Horn Mountains and joins the Big Horn River just north of Greybull. Climate According to the Köppen Climate Classification system, Shell has a cold semi-arid climate A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Gulch Dinosaur Tracksite
Red Gulch Dinosaur Tracksite is an assemblage of fossil dinosaur footprints on public land near Shell, in Big Horn County, Wyoming. They were discovered in 1997 by Erik P. Kvale, a research geologist from the Indiana Geological Survey. The site is managed by the Bureau of Land Management as part of the Red Gulch/Alkali National Back Country Byway and is open to the public. Fossils The fossilized tracks are believed to have been made during the Middle Jurassic Period, 160-180 million years b.p., on what was then a shore of the Sundance Sea. Theropod tracks are thought to be among those discovered, but evidence suggests that the tracks were made by a large, diverse group of dinosaurs. Due to a rarity of Middle Jurassic theropods, the species that made the tracks is currently unknown. The majority of the footprints are in the area dubbed "the ballroom". Besides the trackways, a variety of fossils can be found, including belemnites, crinoids, and shrimp burrows. Geology The tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liopleurodon
''Liopleurodon'' (; meaning 'smooth-sided teeth') is an extinct genus of large, carnivorous marine reptile belonging to the Thalassophonea, a clade of short-necked pliosaurid plesiosaurs. ''Liopleurodon'' lived from the Callovian Stage of the Middle Jurassic to the Kimmeridgian stage of the Late Jurassic Period (c. 166 to 155 mya). It was the apex predator of the Middle to Late Jurassic seas that covered Europe. The largest species, ''L. ferox'', is estimated to have grown up to in length, but could have been larger. The name "Liopleurodon" (meaning "smooth-sided tooth") derives from Ancient Greek words: ', "smooth"; ', "side" or "rib"; and ', "tooth". Discovery and species Even before ''Liopleurodon'' was named, material likely belonging to it was described. In 1841, Hermann von Meyer named the species ''Thaumatosaurus oolithicus'' based on a fragmentary specimen consisting of partial teeth, skull elements, vertebrae, and ribs from deposits in Württemberg, Germany poss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliosaur
Pliosauroidea is an extinct clade of plesiosaurs, known from the earliest Jurassic to early Late Cretaceous. They are best known for the subclade Thalassophonea, which contained crocodile-like short-necked forms with large heads and massive toothed jaws, commonly known as pliosaurs. More primitive non-thalassophonean pliosauroids resembled pleisiosaurs in possessing relatively long necks and smaller heads. They originally included only members of the family Pliosauridae, of the order Plesiosauria, but several other genera and families are now also included, the number and details of which vary according to the classification used. The distinguishing characteristics are a short neck and an elongated head, with larger hind flippers compared to the fore flippers, the opposite of the plesiosaurs. They were carnivorous and their long and powerful jaws carried many sharp, conical teeth. Pliosaurs range from 4 to 15 metres and more in length. Their prey may have included fish, sharks, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalneusaurus
''Megalneusaurus'' is an extinct genus of large pliosaur that lived in the Sundance Sea during the Kimmeridgian, ~156-152 million years ago, in the Late Jurassic. It was named by paleontologist W. C. Knight in 1895. The genus and type species was based upon ribs, vertebrae, a fore-paddle and fragments of the pectoral girdle discovered in the Sundance Formation in Wyoming, USA in 1895.Knight WC. 1895 A new Jurassic plesiosaur from Wyoming. ''Science'' 2: 449. The species named as ''Megalneusaurus rex'' (meaning "great swimming lizard king") in 1898.Knight WC. 1898. Some new Jurassic vertebrates from Wyoming. ''American Journal of Science'' 4: 378-381. However some of this material has since been lost, although new material has been discovered from the same site.Wahl WR, Ross M, Massare JA. 2007. Rediscovery of Wilbur Knight’s ''Megalneusaurus rex'' site: new material from an old pit. ''Paludicola'' 6 (2): 94-104. Based upon the bones very large size, it appears to have grown to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Reptile
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. The earliest marine reptile mesosaurus (not to be confused with mosasaurus), arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs (these two orders were once thought united in the group "Enaliosauria", a classification now cladistically obsolete), mosasaurs, nothosaurs, placodonts, sea turtles, thalattosaurs and thalattosuchians. Most marine reptile groups became extinct at the end of the Cretaceous period, but some still existed during the Cenozoic, most importantly the sea turtles. Other Cenozoic marine reptiles included the bothremydids, palaeophiid snakes, a few choristoderes such as ''Simoedosaurus'' and dyrosaurid crocodylomorphs. Various types of marine gavialid crocodilians remained widespread as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution, and some species at least partly inhabited freshwater environments. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous ''Plesiosaurus'', was named in 1821. Since then, more than a hundred valid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptoclididae
Cryptoclididae is a family (biology), family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and crustaceans. The earliest members of the family appeared during the early Bajocian, and they represented the dominant group of long-necked plesiosaurs during the latter half of the Jurassic. Classification In 2010, two supposed late Cretaceous members of the group were reclassified as other kinds of plesiosauroids. ''Kaiwhekea'' was reclassified to Leptocleididae, and ''Aristonectes'' was transferred to Elasmosauridae. Cladogram based on Ketchum and Benson (2010): References External links palaeos.com Cryptoclidids, Jurassic plesiosaurs Cretaceous plesiosaurs Callovian first appearances Late Cretaceous extinctions Prehistoric reptile families {{Jurassic-reptile-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantosaurus
''Pantosaurus'' ("all lizard") is an extinct genus of plesiosaur from the Late Jurassic ( Oxfordian) of what is now Wyoming. It lived in what used to be the Sundance Sea. It was originally named ''Parasaurus'' ("near lizard") by Othniel Charles Marsh in reference to ''Plesiosaurus'', but that name was preoccupied, and Marsh changed it. The species ''Muraenosaurus reedii'' is in fact a junior synonym of ''Pantosaurus''. The holotype YPM 543 is a partial articulated skeleton, partially prepared to yield a distal humerus, four articulated carpals, a fragment of the coracoid, and several isolated cervical vertebrae from the Upper Member of the Sundance Formation. Other material includes USNM 536963, USNM 536965, UW 3, UW 5544 and UW 15938. Palaeobiology ''Pantosaurus'' possesses between 35 and 40 cervical vertebrae, which are very similar in proportion and morphology to those of '' Muraenosaurus leedsii'' from the Oxford Clay Formation (Callovian, Middle Jurassic) of England. The for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Red Gulch Dinosaur Tracksite")
