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Propanoplosaurus
''Propanoplosaurus'' is a genus of herbivorous nodosaurid dinosaur from the Early Cretaceous Patuxent Formation of Maryland, USA. Its type specimen is a natural cast and partial natural mold of a hatchling. Discovery and naming From 1994 on, Ray Stanford uncovered an ichnofauna in Maryland near the border with Washington D.C. Along with dinosaur footprints, the impressions of a neonate nodosaurid, specimen USNM 540686, were found by Stanford in 1997. The type species, ''Propanoplosaurus marylandicus'' was named and described by Stanford, David Weishampel, and Valerie DeLeon in 2011. The generic name combines the Latin prefix ''pro~'' with the name of the genus ''Panoplosaurus'' because the new species lived earlier than — but resembled much — this already described nodosaurid. The specific name (zoology), specific name refers to Maryland. The holotype, USNM 540686, was found in the Patuxent Formation, dating from the late Aptian. It consists of the impressions of the back ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patuxent Formation
The Patuxent Formation is an Early Cretaceous (Aptian)-aged geologic Formation (geology), formation of the Atlantic coastal plain. It is part of the Potomac Group. Description The Patuxent formation was first described by William Bullock Clark in 1897. The formation is primarily unconsolidated white-grey or orange-brown sand and gravel, with minor clay and silt. The sand often contains Kaolinite, kaolinized feldspar, making it an arkose. Clay lumps are common, and sand beds gradually transition to clay. Sandy beds may be Cross-bedding, crossbedded, which is evidence of shallow water origin.The Patuxent is the basal unit of the Coastal Plain sedimentary formations and unconformity, unconformably overlies the crystalline Basement (geology), basement rocks. This underlying unconformity is the subsurface equivalent of the Atlantic Seaboard Atlantic Seaboard fall line, Fall Line. Notable exposures The type locality is the upper and lower valleys of the Little Patuxent River and Big ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Ankylosaur Research
This timeline of ankylosaur research is a chronological listing of events in the History of paleontology, history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spikes and sometimes by a clubbed tail. Although formally trained scientists did not begin documenting ankylosaur fossils until the early 19th century, Native Americans in the United States, Native Americans had a long history of contact with these remains, which were generally interpreted through a mythological lens. The Delaware Indians, Delaware people have stories about smoking the bones of ancient monsters in a magic ritual to have wishes granted and ankylosaur fossils are among the local fossils that may have been used like this. The Native Americans of the modern southwestern United States tell stories about an armored monster named Yeitso that may have been influenced by local ankylosaur fossils. Likewise, ankylosaur remains are among t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nodosaurid
Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the sister taxon to the Ankylosauridae, some analyses recover it as a paraphyletic grade leading to the ankylosaurids. Description Nodosaurids, like their sister group the ankylosaurids, were heavily armored dinosaurs adorned with rows of bony armor nodules and spines (osteoderms), which were covered in keratin sheaths. Ankylosaurians were small- to large-sized, heavily built, quadrupedal, herbivorous dinosaurs, possessing small, leaf-shaped teeth. Unlike ankylosaurids, nodosaurids lacked mace-like tail clubs and instead had more flexible tail tips. Many nodosaurids had spikes projecting outward from their shoulders. One particularly well-preserved nodosaurid "mummy", the holotype of '' Borealopelta markmitchelli'', preserves a nearly complet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 Megaannum#SI prefix multipliers, Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian–Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany and mycology, an isotype is a duplicate of the holotype, generally pieces from the same individual plant or samples from the same genetic individual. A holotype is not necessarily "ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By David B
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion, especially in the context of rank-based (" Linnaean") nomenclature (much less so under phylogenetic nomenclature). If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were presumably set forth in prehistoric times by hunter-gatherers, as suggested by the fairly sophisticated folk taxonomies. Much later, Aristotle, and later still ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian Dinosaurs
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the Western European Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the Cretaceous Period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years, being marked by enhanced silicate weathering, as well as ocean acidification. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma. Stratigraphic definitions The Aptian was named after the small city of Apt in the Provence region of France, which is also known for its crystallized fruits. The original type locality is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Genera
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutionary history, evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, Evolution of birds, having evolved from earlier Theropoda, 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 taxonomy (biology), taxonomic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
In vertebrates, the maxilla (: maxillae ) 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. Anatomy Structure The maxilla is a paired bone - the two maxillae unite with each other at the intermaxillary suture. The maxilla consists of: * The body of the maxilla: pyramid-shaped; has an orbital, a nasal, an infratemporal, and a facial surface; contains the maxillary sinus. * Four processes: ** the zygomatic process ** the frontal process ** the alveolar process ** the palatine process It has three surfaces: * the anterior, posterior, medial Features of the maxilla include: * t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoderm
Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amphibians), various groups of dinosaurs (most notably ankylosaurs and stegosaurians), phytosaurs, aetosaurs, placodonts, and hupehsuchians (marine reptiles with possible ichthyosaur affinities). Osteoderms are uncommon in mammals, although they have occurred in many xenarthrans (armadillos and the extinct glyptodonts and mylodontid ground sloths). The heavy, bony osteoderms have evolved independently in many different lineages. The armadillo osteoderm is believed to develop in subcutaneous dermal tissues. These varied structures should be thought of as anatomical analogues, not homologues, and do not necessarily indicate monophyly. The structures are however derived from scutes, common to all classes of amniotes and are an exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Priconodon
''Priconodon'' (meaning "saw cone tooth") is an extinct genus of ankylosaurian dinosaur (perhaps nodosaurid), mainly known from its large teeth. Its remains have been found in the Aptian-Albian age Lower Cretaceous Arundel Formation of Muirkirk, Prince George's County, Maryland, USA and the Potomac Group, also located in Maryland. As an ankylosaur, ''Priconodon'' would have been a large armored quadrupedal herbivore, though no size estimation has been done due to the scarcity of described remains. History of discovery O. C. Marsh named the genus for USNM 2135, a large worn tooth from what was then called the Potomac Formation. As ankylosaurians were by and large unknown at the time, he compared it to '' Diracodon'' (='' Stegosaurus'') teeth.Marsh, O.C. (1888). Notice of a new genus of Sauropoda and other new dinosaurs from the Potomac Formation. ''American Journal of Science'' 135:89-94. It was not identified as an ankylosaurian until Walter Coombs assigned it to No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
