|
Apsisaurus
''Apsisaurus'' is an extinct genus of Early Permian varanopid synapsids known from Texas of the United States. It was first named by Michel Laurin in 1991 and the type species is ''Apsisaurus witteri''. ''Apsisaurus witteri'' is known from the holotype MCZ 1474, a three-dimensionally preserved partial skeleton including an incomplete skull and mandibles. The skull roof of '' Archeria'' is also articulated to the postcranial skeleton. It was collected in the Archer City Bonebed 1 site, from the Archer City Formation of the Wichita Group, dating to the Early Permian epoch. ''Apsisaurus'' was formerly assigned as an "eosuchian" diapsid. In 2010, it was redescribed by Robert R. Reisz, Michel Laurin and David Marjanović; their phylogenetic analysis found it to be a basal varanopid synapsid. Below is a simplified version of the cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archer City Formation
The Archer City Formation is a Formation (geology), geological formation in north-central Texas, preserving fossils from the Asselian and early Sakmarian Stage (stratigraphy), stages of the Permian Period (geologic time), period. It is the earliest component of the Red Beds of Texas and Oklahoma, Texas red beds, introducing a tropical ecosystem which will persist in the area through the rest of the Cisuralian, Early Permian. The Archer City Formation is preceded by the cool Carboniferous swamp sediments of the Markley Formation, and succeeded by the equally fossiliferous red beds of the Nocona Formation. The Archer City Formation was not named as a unique geological unit until the late 1980s. Older studies generally labelled its outcrops as the Moran Formation, Moran or Putnam Formation, Putnam formations, which are age-equivalent marine units to the southwest. The sediments of the Archer City Formation reconstruct a coastal floodplain crossed by small Meander, meandering rivers a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanopid
Varanopidae is an extinct family of amniotes known from the Late Carboniferous to Middle Permian that resembled monitor lizards (with the name of the group deriving from the monitor lizard genus ''Varanus'') and may have filled a similar niche. Typically, they are considered to be relatively basal synapsids (and thus more closely related to mammals than to reptiles), although some studies from the late 2010s recovered them being taxonomically closer to diapsid reptiles, recent studies from the early 2020s support their traditional placement as synapsids on the basis of high degree of bone labyrinth ossification, maxillary canal morphology and phylogenetic analyses. A varanopid from the late Middle Permian ''Pristerognathus'' Assemblage Zone (Capitanian) is the youngest known varanopid and the last member of the "pelycosaur" group of synapsids. Thus, Varanopidae vanishes from the fossil record at the same time as dinocephalians, plausibly as a result of a major mass extinction eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanopidae
Varanopidae is an extinct family (biology), family of amniotes known from the Late Carboniferous to Middle Permian that resembled monitor lizards (with the name of the group deriving from the monitor lizard genus ''Varanus'') and may have filled a similar niche. Typically, they are considered to be relatively Basal (phylogenetics), basal Synapsida, synapsids (and thus more closely related to mammals than to reptiles), although some studies from the late 2010s recovered them being taxonomically closer to diapsid reptiles, recent studies from the early 2020s support their traditional placement as synapsids on the basis of high degree of bone labyrinth ossification, maxillary canal morphology and phylogenetic analyses. A varanopid from the late Middle Permian Pristerognathus Assemblage Zone, ''Pristerognathus'' Assemblage Zone (Capitanian) is the youngest known varanopid and the last member of the "pelycosaur" group of synapsids. Thus, Varanopidae vanishes from the fossil record at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1991 In Paleontology
Plants Angiosperms Arthropods Insects Mollusca Newly named bivalves Archosauromorphs * Sankar Chatterjee's discovery of a possible Triassic bird, ''Protoavis'', if genuine, would push avian origins back almost 70 million years. The find ignites controversy over the connection between dinosaurs and birds. Newly named dinosaurs Data courtesy of George Olshevsky's dinosaur genera list. Newly named birds Genera no longer considered to be birds * ''Protoavis''. The avian status of ''Protoavis'' has since been almost universally rejected by paleontologists. Pseudosuchians Pterosaurs New taxa Synapsids Non-mammalian References {{portal, Paleontology [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeovenator
''Archaeovenator'' is an extinct genus of Late Carboniferous varanopid synapsids known from Greenwood County, Kansas of the United States. It was first named by Robert R. Reisz and David W. Dilkes in 2003 and the type species is ''Archaeovenator hamiltonensis''. ''Archaeovenator hamiltonensis'' is known from the holotype KUVP 12483, a three-dimensionally preserved, nearly complete and articulated skeleton, including the skull, with limbs and girdles slightly separated from postcranial skeleton. It was collected in the Hamilton Quarry, from the Calhouns Shale Formation of the Shawnee Group, dating to the Virgilian stage (or alternatively late Kasimovian to early Gzhelian stage) of the Late Pennsylvanian Series, about 300 million years ago. The generic name is derived from the Latin ''Archaeo'' and ''venator'', meaning "ancient hunter". The specific name is named after its finding place Hamilton Quarry Hamilton Quarry is a Late Carboniferous lagerstätte near Hamilton, Ka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eosuchia
Eosuchians are an extinct order of diapsid reptiles. Depending on which taxa are included the order may have ranged from the late Carboniferous to the Eocene but the consensus is that eosuchians are confined to the Permian and Triassic. Eosuchia was initially defined to include all "thecodontian" reptiles which did not have an antorbital fenestra but did retain tabulars, postparietals and a large pineal foramen (Broom, 1914). Broom coined the term as a new suborder for ''Youngina''. A definition for inclusion in the order is difficult: it is almost easier to list the primitively-diapsid reptiles that have not been included at one time or another. The order has almost been treated as a dustbin for diapsids that are not obviously lepidosaurian or archosaurian. One consequence has been Romer's suggestion of the alternative order Younginiformes to be applied strictly to those forms with the primitive diapsid form, in particular, a complete lowermost arch as the quadratojugal and j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 1991
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''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of ''Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before print. The ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisuralian Synapsids Of North America
The Cisuralian, also known as the Early Permian, is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Ma. In the regional stratigraphy of southwestern North America, the Cisuralian encompasses two series: the Wolfcampian (Asselian to mid-Artinskian) and Leonardian (mid-Artinskian to Kungurian). The series saw the appearance of beetles and flies and was a relatively stable warming period of about 21 million years. Name and background The Cisuralian is the first series or epoch of the Permian. The Cisuralian was preceded by the last Pennsylvanian epoch (Gzhelian) and is followed by the Permian Guadalupian Epoch. The name "Cisuralian" was proposed in 1982, and approved by the International Subcommission on Permian Stratigraphy in 1996. The Cisuralian Epoch is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Synapsid Genera
Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by the 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. It is based on an old conception of history that without written records there could be no history. The most common conception today is that history is based on evidence, however the concept of prehistory hasn't been completely discarded. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycterosaurus
''Mycterosaurus'' (Greek as mykter/mykteros meaning nose/snout, sauros meaning "lizard") is an extinct genus of amniotes belonging to the family Varanopidae. It is classified in the varanopid subfamily Mycterosaurinae. ''Mycterosaurus'' is the most primitive member of its family, existing from 290.1 to 272.5 MYA, known to Texas and Oklahoma. It lacks some features that its advanced relatives have. ''Mycterosaurus'' is a relatively small carnivore, estimated to be around 60 cm (23 inches) long with synonyms of ''Eumatthevia bolli'', and possibly ''Basicranodon fortsillensis''. Restored, ''Mycterosaurus'' appears spindly and grotesque in contrast to the majority of "pelycosaurs" in its proportions and especially unlike edaphosaurids, which are commonly stocky in build. The number of valid ''Mycterosaurus'' species have varied over the years, with a total of two classifications of ''Mycterosaurus longiceps'' and ''Mycterosaurus smithae.'' However, recent analysis has led ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesenosaurus
''Mesenosaurus'' is an extinct genus of synapsid belonging to the family Varanopidae. This genus includes two species: the type species ''Mesenosaurus romeri'' from the middle Permian (upper Kazanian) Mezen River Basin of northern Russia, and ''Mesenosaurus efremovi'' from the early Permian (Artinskian) Richards Spur locality (Oklahoma, United States). ''M. romeri''’s stratigraphic range is the middle to late Guadalupian while ''M. efremovi''’s stratigraphic range is the Cisuralian. Etymology Famous Russian paleontologist, Ivan Efremov, established ''Mesenosaurus'' as a genus. The genus name means “lizard from Mezen” while the specific epithet is given in honor of Alfred Romer. ''Mesenosaurus efremovi'' was named in honor of Ivan Efremov, who erected the genus. Description ''Mesenosaurus'' are small sized varanopid synapsids. They are characterized by mainly cranial features. Many of the postcranial features of this genus have not been analyzed fully due to a lack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
