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Ornithomimid Hand
Ornithomimidae (meaning "bird-mimics") is a family of theropod dinosaurs which bore a superficial resemblance to modern ostriches. Ornithomimids were fast, omnivorous or herbivorous dinosaurs known mainly from the Late Cretaceous Period of Laurasia (now Asia and North America), though they have also been reported from the Lower Cretaceous Wonthaggi Formation of Australia. Description The skulls of ornithomimids were small, with large eyes, above relatively long and slender necks. All had toothless beaks. The fore limbs ('arms') were long and slender and bore powerful claws. The hind limbs were long and powerful, with a long foot and short, strong toes terminating in hooflike claws. Ornithomimids were probably among the fastest of all dinosaurs.Holtz, Thomas R. Jr. (2012) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'Winter 2011 Appendix./ref> Like many other coelurosaurs, the ornithomimid hide was feathered rather than scaly. Biology C ... [...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] |
Theropod
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Theropods first appeared during the Carnian age of the late Triassic period 231.4 million years ago ( Ma) and included all the large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 10,500 living species. Biology Diet and teeth Theropods exhibit a wide range of diets, from insectivores to herbivores and carnivores. Strict carnivory has always been considered the ancestral diet for theropods as a group, and a wider variety of diets was historically considered a characteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathemeral
Cathemerality, sometimes called metaturnality, is an organismal activity pattern of irregular intervals during the day or night in which food is acquired, socializing with other organisms occurs, and any other activities necessary for livelihood are undertaken. This activity differs from the generally monophasic pattern (sleeping once per day) of nocturnal and diurnal species as it is polyphasic (sleeping 4-6 times per day) and is approximately evenly distributed throughout the 24-hour cycle. Many animals do not fit the traditional definitions of being strictly nocturnal, diurnal, or crepuscular, often driven by factors that include the availability of food, predation pressure, and variable ambient temperature. Although cathemerality is not as widely observed in individual species as diurnality or nocturnality, this activity pattern is seen across the mammal taxa, such as in lions, coyotes, and lemurs. Cathemeral behaviour can also vary on a seasonal basis over an annual per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerotic Ring
Sclerotic rings are rings of bone found in the eyes of many animals in several groups of vertebrates, except for mammals and crocodilians. They can be made up of single bones or multiple segments and take their name from the sclera. They are believed to have a role in supporting the eye, especially in animals whose eyes are not spherical, or which live underwater. Fossil sclerotic rings are known for a variety of extinct animals, including ichthyosaurs, pterosaurs, and dinosaurs, but are often not preserved. File:Tawny Frogmouth Skull.jpg, A skull of an extant tawny frogmouth, showing large sclerotic rings. File:Uroplatus_phantasticus_skull1.jpg, A skull of an extant satanic leaf-tailed gecko, showing large sclerotic rings. File:Viatkogorgon skull.png, Skull and sclerotic ring of the gorgonopsian ''Viatkogorgon''. File:Prosaurolophus maximus3.JPG, Sclerotic ring of the hadrosaur ''Prosaurolophus ''Prosaurolophus'' (; meaning "before ''Saurolophus''", in comparison to the late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feathered Dinosaur
A feathered dinosaur is any species of dinosaur possessing feathers. While this includes all species of birds, there is a hypothesis that many, if not all non-avian dinosaur species also possessed feathers in some shape or form. It has been suggested that feathers had originally functioned as thermal insulation, as it remains their function in the down feathers of infant birds today, prior to their eventual modification in birds into structures that support flight. Since scientific research began on dinosaurs in the early 1800s, they were generally believed to be closely related to modern reptiles, such as lizards. The word ''dinosaur'' itself, coined in 1842 by paleontologist Richard Owen, comes from the Greek for 'terrible lizard'. This view began to shift during the so-called dinosaur renaissance in scientific research in the late 1960s, and by the mid-1990s significant evidence had emerged that dinosaurs were much more closely related to birds, which descended directly from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelurosaur
Coelurosauria (; from Greek, meaning "hollow tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyrannosaurs, ornithomimosaurs, and maniraptorans; Maniraptora includes birds, the only known dinosaur group alive today. Most feathered dinosaurs discovered so far have been coelurosaurs. Philip J. Currie had considered it likely and probable that all coelurosaurs were feathered. However, several skin impressions found for some members of this group show pebbly, scaly skin, indicating that feathers did not completely replace scales in all taxa. In the past, Coelurosauria was used to refer to all small theropods, but this classification has since been abolished. Anatomy Bodyplan The studying of anatomical traits in coelurosaurs indicates that the last common ancestor had evolved the ability to eat and digest plant matter, adapting to an omnivo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beak
The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for food, courtship, and feeding young. The terms ''beak'' and ''rostrum'' are also used to refer to a similar mouth part in some ornithischians, pterosaurs, cetaceans, dicynodonts, anuran tadpoles, monotremes (i.e. echidnas and platypuses, which have a beak-like structure), sirens, pufferfish, billfishes and cephalopods. Although beaks vary significantly in size, shape, color and texture, they share a similar underlying structure. Two bony projections – the upper and lower mandibles – are covered with a thin keratinized layer of epidermis known as the rhamphotheca. In most species, two holes called ''nares'' lead to the respiratory system. Etymology Although the word "beak" was, in the past, generally restricted to the sharpened bills o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wonthaggi Formation
The Wonthaggi Formation is an informal geological formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is part of the Strzelecki Group within the Gippsland Basin. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; ''et al.'' (2004). "Dinosaur distribution (Early Cretaceous, Australasia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 573-574. . It is partially equivalent to the Eumeralla Formation. Geology The Wonthaggi Formation was deposited within the extensional rift valley formed between Australia and Antarctica. The lithology primarily consists of fluvially deposited siliciclastics derived from volcanic rocks of the Whitsunday Silicic Large Igneous Province to the East, with suggestions that the sediments either originated from braided river and sheet flood deposits, or meandering river systems on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Cretaceous
Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eighteen miles southwest of Gloucester and fifteen miles northeast of Bristol. Lower Wick is within the civil ... Gloucestershire, England See also * Nizhny {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area of , about 30% of Earth's total land area and 8.7% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East–West cultural, linguistic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laurasia
Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Asia. Laurentia, Avalonia, Baltica, and a series of smaller terranes, collided in the Caledonian orogeny c. 400 Ma to form Laurussia (also known as Euramerica, or the Old Red Sandstone Continent). Laurussia then collided with Gondwana to form Pangaea. Kazakhstania and Siberia were then added to Pangaea 290–300 Ma to form Laurasia. Laurasia finally became an independent continental mass when Pangaea broke up into Gondwana and Laurasia. Terminology and origin of the concept Laurentia, the Palaeozoic core of North America and continental fragments that now make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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