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Protostega
''Protostega'' ('first roof') is an extinct genus of sea turtle containing a single species, ''Protostega gigas''. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas (''Hesperornis'' zone, dated to 83.5 million years agoCarpenter, K. (2003). "Vertebrate Biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale)." ''High-Resolution Approaches in Stratigraphic Paleontology'', 21: 421-437. ), time-equivalent beds of the Mooreville Chalk Formation of Alabama and Campanian beds of the Rybushka Formation (Saratov Oblast, Russia). Fossil specimens of this species were first collected in 1871, and named by Edward Drinker Cope in 1872. With a total length of , it is the second-largest sea turtle that ever lived, second only to the giant '' Archelon'', and one of the three largest turtle of all time along '' Archelon'' and '' Gigantatypus''. Discovery and History The first known ''Protostega'' specimen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostega Plastron View
''Protostega'' ('first roof') is an extinct genus of sea turtle containing a single species, ''Protostega gigas''. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas (''Hesperornis'' zone, dated to 83.5 million years agoCarpenter, K. (2003). "Vertebrate Biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale)." ''High-Resolution Approaches in Stratigraphic Paleontology'', 21: 421-437. ), time-equivalent beds of the Mooreville Chalk Formation of Alabama and Campanian beds of the Rybushka Formation (Saratov Oblast, Russia). Fossil specimens of this species were first collected in 1871, and named by Edward Drinker Cope in 1872. With a total length of , it is the second-largest sea turtle that ever lived, second only to the giant ''Archelon'', and one of the three largest turtle of all time along ''Archelon'' and '' Gigantatypus''. Discovery and History The first known ''Protostega'' specimen (YPM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostega Gigas
''Protostega'' ('first roof') is an extinct genus of sea turtle containing a single species, ''Protostega gigas''. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas (''Hesperornis'' zone, dated to 83.5 million years agoCarpenter, K. (2003). "Vertebrate Biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale)." ''High-Resolution Approaches in Stratigraphic Paleontology'', 21: 421-437. ), time-equivalent beds of the Mooreville Chalk Formation of Alabama and Campanian beds of the Rybushka Formation (Saratov Oblast, Russia). Fossil specimens of this species were first collected in 1871, and named by Edward Drinker Cope in 1872. With a total length of , it is the second-largest sea turtle that ever lived, second only to the giant ''Archelon'', and one of the three largest turtle of all time along ''Archelon'' and '' Gigantatypus''. Discovery and History The first known ''Protostega'' specimen (YPM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostegidae
Protostegidae is a family of extinct sea turtle, marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, ''Archelon'', had a head long. Like most sea turtles, they had flattened bodies and flipper (anatomy), flippers for front appendages; protostegids had minimal carapace, shells like Dermochelyidae, leatherback turtles of modern times. Anatomy As some of the first sea turtle, marine turtles, the protostegids set the general body plan for future species of sea turtles. They had a generally depressed turtle body plan, complete with four limbs, a short tail, and a large head at the end of a relatively short neck. Like other sea turtles, they possessed oar-like front appendages especially evolved for swimming in the open ocean. Similar to the still-extant taxon, extant, possibly closely related Dermochelyidae, protostegids possessed extremely reduced carapaces. Some specimens had skeletal protrusio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archelon
''Archelon'' is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring from head to tail and in body mass. It is known only from the Dakota Pierre Shale and has one species, ''A. ischyros''. In the past, the genus also contained ''A. marshii'' and ''A. copei'', though these have been reassigned to '' Protostega'' and ''Microstega'', respectively. The genus was named in 1895 by American paleontologist George Reber Wieland based on a skeleton from South Dakota, who placed it into the extinct family Protostegidae. The leatherback sea turtle (''Dermochelys coriacea'') was once thought to be its closest living relative, but now, Protostegidae is thought to be a completely separate lineage from any living sea turtle. ''Archelon'' had a leathery carapace instead of the hard shell seen in sea turtles. The carapace may have featured a row of small ridges, each peaking at in height. It had an esp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mooreville Chalk Formation
The Mooreville Chalk is a geological formation in North America, within the U.S. states of Alabama and Mississippi, which were part of the subcontinent of Appalachia. The strata date back to the early Santonian to the early Campanian stage of the Late Cretaceous. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment. It is a unit of the Selma Group and consists of the upper Arcola Limestone Member and an unnamed lower member. Dinosaur, mosasaur, and primitive bird remains are among the fossils that have been recovered from the Mooreville Chalk Formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. . Fish Cartilaginous fish Bony fish Reptiles Dinosaurs Indeterminate hadrosaurid, nodosaurid, dinosaur egg, and ornithomimosaur fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Turtle
Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley sea turtles. All six of the sea turtle species present in US waters (all of those listed above except the flatback) are listed as endangered and/or threatened under the Endangered Species Act. The seventh sea turtle species is the flatback, which exists in the waters of Australia, Papua New Guinea and Indonesia. Sea turtles can be separated into the categories of hard-shelled (cheloniid) and leathery-shelled ( dermochelyid).Wyneken, J. 2001. The Anatomy of Sea Turtles. U.S Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-470, 1-172 pp. There is only one dermochelyid species which is the leatherback sea turtle. Description For each of the seven types of sea turtles, females and males are the sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermochelyidae
Dermochelyidae is a family of turtles which has seven extinct genera and one extant genus, including the largest living sea turtles. Classification of known genera The following list of dermochelyid species was published by Hirayama and Tong in 2003, unless otherwise noted. * ''Arabemys crassiscutata'' * †''Eosphargis breineri'' * ''Mesodermochelys undulatus'' *Subfamily Dermochelyinae ** †''Cosmochelys'' ** ''Dermochelys coriacea'' – leatherback sea turtle ** †''Psephophorus ''Psephophorus'' is an extinct genus of sea turtle that lived from the Oligocene to the Pliocene. Its remains have been found in Europe, Africa, North America, and New Zealand. It was first named by Hermann von Meyer in 1847, and contains seve ...'' Phylogeny Evers et al. (2019): References Bibliography * External linksFamily Dermochelyidae (Leatherback turtles) from Turtles of the World by C.H. Ernst, R.G.M. Altenburg & R.W. Barbour {{Taxonbar, from=Q2738058 Taxa named by Leopo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossification
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue ( mesenchyme), while endochondral ossification involves cartilage as a precursor. In fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in fractures of long bones treated by plaster of Paris, whereas fractures treated by open reduction and internal fixation with metal plates, screws, pins, rods and nails may heal by intramembranous osteogenesis. Heterotopic ossification is a process resulting in the formation of bone tissue that is often atypical, at an extraskeletal location. Calcification is often confused with ossification. Calcification is sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron. Crustaceans In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and thorax, as distinct from the abdomen behind). Where it projects forward beyond the eyes, this projection is called a rostrum (anatomy), rostrum. The carapace is Calcification, calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and Isopoda, isopods, but isopods only have a developed "cephalic shield" carapace covering the head. Arachnids In arachnids, the carapace is formed by the fusion of prosomal tergites into a single Plate (animal anatomy), plate which carries the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leatherback Sea Turtle
The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to and weights of . It is the only living species in the genus ''Dermochelys'' and family Dermochelyidae. It can easily be differentiated from other modern sea turtles by its lack of a bony shell; instead, its carapace is covered by oily flesh and flexible, leather-like skin, for which it is named. Taxonomy and evolution Taxonomy ''Dermochelys coriacea'' is the only species in genus ''Dermochelys''. The genus, in turn, contains the only extant member of the family Dermochelyidae. Domenico Agostino Vandelli named the species first in 1761 as ''Testudo coriacea'' after an animal captured at Ostia and donated to the University of Padua by Pope Clement XIII. In 1816, French zoologist Henri Blainville coined the term ''Dermochelys''. The leatherback was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Sea Turtle
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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