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Wannaganosuchus
''Wannaganosuchus'' (meaning "Wannagan crocodile", in reference to the Wannagan Creek site where it was discovered) is an extinct genus of small alligatorid crocodylian. It was found in Late Paleocene-age rocks of Billings County, North Dakota, United States. History and description ''Wannaganosuchus'' is based on SMM P76.28.247, a mostly complete skull and postcranial skeleton missing some vertebrae, coracoids, part of the feet, ribs, and other pieces. A few small bony scutes are also assigned to the genus, but not to the type specimen. SMM P76.28.247 was found semi-articulated in the lower part of the Bullion Creek Formation, near the base of a lignitic clay layer deposited in a marsh setting on a floodplain. ''Wannaganosuchus'' was named in 1982 by Bruce R. Erickson. The type species is ''W. brachymanus''; the specific name means "short forefoot". The skull of SMM P76.28.247 was low, without elevated rims over the eyes, and was long. The snout was sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allognathosuchus
''Allognathosuchus'' (meaning "other jaw crocodile") is an extinct genus of alligatorine crocodylian with a complicated taxonomic history. It was named in 1921. Description ''Allognathosuchus'' was a medium-sized predator up to 1.5 m in length. This alligatorine is known for its stout jaws and bulbous teeth, found near the rear of the tooth row in upper and lower jaws. These adaptations have historically been interpreted as having been for crushing mollusks. Isolated bulbous teeth are often assigned to this genus, although such teeth are known from other crocodyliform lineages. Taxonomy The type species, ''A. polyodon'', is from the Eocene-age Bridger Formation of Wyoming; it is based on fossils that are difficult to distinguish from other Paleogene alligatorids. ''A. heterodon'' is from the Eocene-age Wasatch Formation of Wyoming, ''A. wartheni'' is from the Eocene-age Wildwood Formation (also known as the "Wildwood alligatorid" and possibly two species), and ''A. w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alligatorid
The family Alligatoridae of crocodylians includes alligators, caimans and their extinct relatives. Phylogeny The superfamily Alligatoroidea includes all crocodilians (fossil and extant) that are more closely related to the American alligator than to either the Nile crocodile or the gharial. This is a stem-based definition for alligators, and is more inclusive than the crown group Alligatoridae. As a crown group, Alligatoridae only includes the last common ancestor of all extant (living) alligators, caimans, and their descendants (living or extinct), whereas Alligatoroidea, as a stem-based group, also includes more basal extinct alligator ancestors that are more closely related to living alligators than to crocodiles or gavialids. When considering only living taxa (neontology), this makes Alligatoroidea and Alligatoridae redundant. The simplified cladogram below shows Alligatoridae's relationships to other extant (living) crocodilians. The below detailed cladogram shows on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bruce Erickson (paleontologist)
Bruce R. Erickson (1933 – January 16, 2022) was an American paleontologist and the former Fitzpatrick Chair of Paleontology at the Science Museum of Minnesota. During the course of his lifetime and his 55 years as a paleontologist, he has "collected about a million specimens" and discovered fifteen new types of plants and ancient animal species. His collection includes "a triceratops skeleton" that he discovered in 1961 at the Hell Creek Formation that is considered to be "one of the rarest in the world".Estrada, Heron Marquez"Book fleshes out a career studying dinosaur bones" Star Tribune, April 27, 2003 His research has focused almost entirely on the Paleocene era in history. Biography According to Erickson, his interest in paleontology began when he was ten years old and he came across a geologist investigating rocks along the bank of the Mississippi River.Brody, Jane E."26 Years Deep in the Paleocene" Los Angeles Times, September 3, 1996 Career In the 1960s, Erickson spen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wannagan Creek Site
The Wannagan Creek site is a fossil site found just west of the South Unit of Theodore Roosevelt National Park of North Dakota, USA. The site is Paleocene in age, approximately 60 million years old. Paleontologists of the Science Museum of Minnesota have studied the site for nearly thirty years. The site is thought to represent a paleoenviroment of subtropical swampy lowland and forests. Preservation is excellent for both the flora and fauna of the site. Trace fossils of crocodilians and other vertebrates have also been discovered. Topography/Geology The topography of the site is that of a badland, due to the downcutting of the Little Missouri River. The rock units are likely sediments derived from the Laramide orogeny deposited in an ecosystem dominated by rivers, streams, ponds, lakes, and swamps. The Wannagan Site is found in the upper portion of the Tongue River Formation (formerly Bullion Creek Formation). The rocks of this deposit, reaching a thickness of over 60 m, con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Paleocene
The Thanetian is, in the ICS Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene Epoch or Series. It spans the time between . The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age (part of the Eocene). The Thanetian is sometimes referred to as the Late Paleocene. Stratigraphic definition The Thanetian was established by Swiss geologist Eugène Renevier in 1873. The Thanetian is named after the Thanet Formation, the oldest Cenozoic deposit of the London Basin, which was first identified in the area of Kent (southern England) known as the Isle of Thanet. The base of the Thanetian Stage is laid at the base of magnetic chronozone C26n. The references profile (Global Boundary Stratotype Section and Point) is in the Zumaia section (43° 18'N, 2° 16'W) at the beach of Itzurun, Pais Vasco, northern Spain. Fossils of the unicellular planktonic marine coccolithophore '' Areoligeria gippingensis'' make their first appeara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw. Structure In humans, the maxilla consists of: * The body of the maxilla * Four processes ** the zygomatic process ** the frontal process of maxilla ** the alveolar process ** the palatine process * three surfaces – anterior, posterior, medial * the Infraorbital foramen * the maxillary sinus * the incisive foramen Articulations Each maxilla articulates with nine bones: * two of the cranium: the frontal and ethmoid * seven of the face: the nasal, zygomatic, lacrimal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salviniales
The order Salviniales (formerly known as the Hydropteridales and including the former Marsileales) is an order of ferns in the class Polypodiopsida. Description Salviniales are all aquatic and differ from all other ferns in being heterosporous, meaning that they produce two different types of spores (megaspores and microspores) that develop into two different types of gametophytes (female and male gametophytes, respectively), and in that their gametophytes are endosporic, meaning that they never grow outside the spore wall and cannot become larger than the spores that produced them. The megasporangia each produce a single megaspore. In being heterosporus with endosporic gametophytes they are more similar to seed plants than to other ferns. The fertile and sterile leaves are dimorphic, taking on a different shape, and leaves bear anastomosing veins. Aerenchyma is frequently present in roots, shoots, and petioles (leaf stalks). The ferns of this order vary radically in form an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxodium
''Taxodium'' is a genus of one to three species (depending on taxonomic opinion) of extremely flood-tolerant conifers in the cypress family, Cupressaceae. The generic name is derived from the Latin word ''taxus'', meaning "yew", and the Greek word ''εἶδος'' (''eidos''), meaning "similar to." Within the family, ''Taxodium'' is most closely related to Chinese swamp cypress (''Glyptostrobus pensilis'') and sugi (''Cryptomeria japonica''). Species of ''Taxodium'' occur in the southern part of the North American continent and are deciduous in the north and semi-evergreen to evergreen in the south. They are large trees, reaching tall and (exceptionally ) trunk diameter. The needle-like leaves, long, are borne spirally on the shoots, twisted at the base so as to appear in two flat rows on either side of the shoot. The cones are globose, diameter, with 10-25 scales, each scale with 1-2 seeds; they are mature in 7–9 months after pollination, when they disintegrate to relea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lilium
''Lilium'' () is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much of the world. Most species are native to the northern hemisphere and their range is temperate climates and extends into the subtropics. Many other plants have "lily" in their common names, but do not belong to the same genus and are therefore not true lilies. Description Lilies are tall perennials ranging in height from . They form naked or tunicless scaly underground bulbs which are their organs of perennation. In some North American species the base of the bulb develops into rhizomes, on which numerous small bulbs are found. Some species develop stolons. Most bulbs are buried deep in the ground, but a few species form bulbs near the soil surface. Many species form stem-roots. With these, the bulb grows naturally at some depth in the soil, and each ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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