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Argentinadraco
''Argentinadraco'' (meaning "Argentina dragon") is an extinct genus of azhdarchoid pterosaur from the Late Cretaceous Portezuelo Formation of Argentina. It contains a single species, ''A. barrealensis'', named in 2017 by Alexander Kellner and Jorge Calvo. ''Argentinadraco'' is unusual for bearing a bottom jaw with a concave bottom edge, as well as a pair of ridges and depressions on the top surface. These features distinguish it from all other azhdarchoid groups, complicating its assignment, but it may belong to the Chaoyangopteridae. The ridges on the lower jaw may have been used to feed on small invertebrates in loose sediment within the system of lakes and rivers that it resided in. Discovery and naming ''Argentinadraco'' is known from a single partial lower jaw, missing the rear end. The specimen is also compressed, especially near the tip of the jaw. Catalogued as MUCPv-1137 in the Centro Paleontológico Lago Barreales (CePaLB) of the National University of Comahue, it wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentinadraco Jaw Posterodorsal Inset
''Argentinadraco'' (meaning "Argentina dragon") is an extinct genus of azhdarchoid pterosaur from the Late Cretaceous Portezuelo Formation of Argentina. It contains a single species, ''A. barrealensis'', named in 2017 by Alexander Kellner and Jorge Calvo. ''Argentinadraco'' is unusual for bearing a bottom jaw with a concave bottom edge, as well as a pair of ridges and depressions on the top surface. These features distinguish it from all other azhdarchoid groups, complicating its assignment, but it may belong to the Chaoyangopteridae. The ridges on the lower jaw may have been used to feed on small invertebrates in loose sediment within the system of lakes and rivers that it resided in. Discovery and naming ''Argentinadraco'' is known from a single partial lower jaw, missing the rear end. The specimen is also compressed, especially near the tip of the jaw. Catalogued as MUCPv-1137 in the Centro Paleontológico Lago Barreales (CePaLB) of the National University of Comahue, it wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaoyangopteridae
Chaoyangopteridae (or chaoyangopterids) is a family of pterosaurs within the larger group Azhdarchoidea. Chaoyangopterids lived mostly during the Early Cretaceous period, though possible members, ''Microtuban'', '' Xericeps'' and ''Argentinadraco'', may extend the fossil range to the Late Cretaceous. History The clade Chaoyangopteridae was first defined in 2008 by Lü Junchang and David Unwin as: "'' Chaoyangopterus'', '' Shenzhoupterus'', their most recent common ancestor and all taxa more closely related to this clade than to '' Tapejara'', ''Tupuxuara'' or ''Quetzalcoatlus''". Based on neck and limb proportions, it has been suggested they occupied a similar ecological niche to that of azhdarchid pterosaurs, though it is possible they were more specialized as several genera occur in Liaoning, while azhdarchids usually occur by one genus in a specific location. Description Chaoyangopterids are distinguished from other pterosaurs by several traits of the nasoantorbital fenestra, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azhdarchoidea
Azhdarchoidea (or azhdarchoids) is a group of pterosaurs within the suborder Pterodactyloidea, more specifically within the group Ornithocheiroidea. Pterosaurs belonging to this group lived throughout the Early Cretaceous, Early and Late Cretaceous periods, with one tentative member, ''Tendaguripterus'', that lived in the Late Jurassic period. The largest azhdarchoids include members of the family Azhdarchidae, examples of these are ''Quetzalcoatlus'', ''Hatzegopteryx'', and ''Arambourgiania''. The Azhdarchoidea has been recovered as either closely related to the Ctenochasmatoidea, as the sister taxon of the Pteranodontoidea within the Ornithocheiroidea, or within the Tapejaroidea, which in turn was also within the Ornithocheiroidea. Classification Azhdarchoidea was given a phylogenetic definition by David Unwin in 2003. Unwin defined the group as the most recent common ancestor of ''Quetzalcoatlus'' and ''Tapejara (pterosaur), Tapejara'', and all its descendants.Unwin, D. M., (20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azhdarchoidea
Azhdarchoidea (or azhdarchoids) is a group of pterosaurs within the suborder Pterodactyloidea, more specifically within the group Ornithocheiroidea. Pterosaurs belonging to this group lived throughout the Early Cretaceous, Early and Late Cretaceous periods, with one tentative member, ''Tendaguripterus'', that lived in the Late Jurassic period. The largest azhdarchoids include members of the family Azhdarchidae, examples of these are ''Quetzalcoatlus'', ''Hatzegopteryx'', and ''Arambourgiania''. The Azhdarchoidea has been recovered as either closely related to the Ctenochasmatoidea, as the sister taxon of the Pteranodontoidea within the Ornithocheiroidea, or within the Tapejaroidea, which in turn was also within the Ornithocheiroidea. Classification Azhdarchoidea was given a phylogenetic definition by David Unwin in 2003. Unwin defined the group as the most recent common ancestor of ''Quetzalcoatlus'' and ''Tapejara (pterosaur), Tapejara'', and all its descendants.Unwin, D. M., (20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azhdarchidae
Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cretaceous as well (late Berriasian age, about 140 million years ago). Azhdarchids included some of the largest known flying animals of all time, but smaller cat-size members have also been found. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the Azhdarchinae to include the pterosaurs ''Azhdarcho'', ''Quetzalcoatlus'', and ''Titanopteryx'' (now known as ''Arambourgiania''). They were among the last known surviving members of the pterosaurs, and were a rather successful group with a worldwide distribution. By the time of the end-Cretaceous mass extinction, most pterosaur families except for the Azhdarchidae disappear from the fossil record, but recent studies indicate a wealth of pterosaurian fauna, including pteran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Kellner
Alexander Wilhelm Armin Kellner (born September 26, 1961) is a Brazilian geologist and paleontologist who is a leading expert in the field of studying pterosaurs. His research has focused mainly on fossil reptiles from the Cretaceous Period, including extinct dinosaurs and crocodylomorphs. Kellner has over 500 publications to his name, has published more than 160 primary studies and two science books. He has participated in paleontological expeditions to many locations including Brazil, Chile, Iran, the United States, Argentina, China, and Antarctica. His scientific achievements include the description of more than thirty species. For his work he has received several honors and prizes, including the TWAS Prize for Earth Sciences from The World Academy of Sciences and admission to the National Order of Scientific Merit (class Comendador), one Brazil's most prestigious awards. Biography Kellner was born in Vaduz, Liechtenstein, son of a German father and Austrian mother. In hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portezuelo Formation
The Portezuelo Formation is a geologic formation of Late Cretaceous ( Late Turonian to Early Coniacian) age, outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina.Portezuelo Formation at .org It is the fourth-oldest formation in the and the older of the two formations in the Río Neuquén Subgroup. Formerly, that subgroup was treated as a formation, and the Portezuelo Formation was known as the Portezuelo Member. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by the Cenomanian Stage and underlies the Coniacian Stage. At the beginning of the Turonian an oceanic anoxic event (OAE 2) took place, also referred to as the Cenomanian-Turonian boundary event or the "Bonarelli Event". Stratigraphic definition The Turonian (French: ''Turonien'') was defined by the French paleontologist Alcide d'Orbigny (1802–1857) in 1842. Orbigny named it after the French city of Tours in the region of Touraine (department Indre-et-Loire), which is the original type locality. The base of the Turonian Stage is defined as the place where the ammonite species '' Watinoceras devonense'' first appears in the stratigraphic column. The official reference profile (the GSSP) for the base of the Turonian is located in the Roc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a phylogenetic tree#Rooted tree, rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, Phylogenetic diversity, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and cladogenesis, diversification. However, such a correlation does not make a given ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandibular Symphysis
In human anatomy, the facial skeleton of the skull the external surface of the mandible is marked in the median line by a faint ridge, indicating the mandibular symphysis (Latin: ''symphysis menti'') or line of junction where the two lateral halves of the mandible typically fuse at an early period of life (1-2 years). It is not a true symphysis as there is no cartilage between the two sides of the mandible. This ridge divides below and encloses a triangular eminence, the mental protuberance, the base of which is depressed in the center but raised on either side to form the mental tubercle. The lowest (most inferior) end of the mandibular symphysis — the point of the chin — is called the "menton". It serves as the origin for the geniohyoid and the genioglossus muscles. Other animals Solitary mammalian carnivores that rely on a powerful canine bite to subdue their prey have a strong mandibular symphysis, while pack hunters delivering shallow bites have a weaker one. When filter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Tissue
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialized connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralization of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mineralized ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tapejaridae
Tapejaridae (from a Tupi word meaning "the old being") are a family of pterodactyloid pterosaurs from the Cretaceous period. Members are currently known from Brazil, England, Hungary, Morocco, Spain, the United States, and China. The most primitive genera were found in China, indicating that the family has an Asian origin. Description Tapejarids were small to medium-sized pterosaurs with several unique, shared characteristics, mainly relating to the skull. Most tapejarids possessed a bony crest arising from the snout (formed mostly by the premaxillary bones of the upper jaw tip). In some species, this bony crest is known to have supported an even larger crest of softer, fibrous tissue that extends back along the skull. Tapejarids are also characterized by their large nasoantorbital fenestra, the main opening in the skull in front of the eyes, which spans at least half the length of the entire skull in this family. Their eye sockets were small and pear-shaped. Studies of tapejarid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
