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San Angelo Formation
The San Angelo Formation is a geologic formation in Texas. It preserves fossils dating back to the Permian period. It is one of the geologically youngest formations to preserve fossils of pelycosaurs. Stratigraphy and age The San Angelo Formation belongs to the Kungurian stage of the Cisuralian series. It underlies the Blaine Formation, which is either upper Kungurian or lower Guadalupian. Fossil content Everett C. Olson regarded the San Angelo Formation as preserving some of the oldest known therapsids, several of which he classified in a taxon he called Eotheriodonta. These taxa are now interpreted as caseids and sphenacodontids, not therapsids. Synapsids See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to paleontological research occurring within or conducted by people from the U.S. state of Texas. Author Marian Murray has remarked that "Texas is as big for fossils as it is for everything else." Some of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenacodontids
Sphenacodontidae (Greek: "wedge point tooth family") is an extinct family of small to large, advanced, carnivorous, Late Pennsylvanian to middle Permian pelycosaurs. The most recent one, ''Dimetrodon angelensis'', is from the late Kungurian or early Roadian San Angelo Formation. However, given the notorious incompleteness of the fossil record, a recent study concluded that the Sphenacodontidae may have become extinct as recently as the early Capitanian. Primitive forms were generally small (60 cm to 1 meter), but during the later part of the early Permian these animals grew progressively larger (up to 3 meters or more), to become the top predators of their environments. Sphenacodontid fossils are so far known only from North America and Europe. Characteristics The skull is long, deep and narrow, an adaptation for strong jaw muscles. The front teeth are large and dagger-like, whereas the teeth in the sides and rear of the jaw are much smaller (hence the name of the well-kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mastersonia
''Mastersonia'' is an extinct genus of non-mammalian therapsids from the Lower Permian of San Angelo Formation, Texas. It is only known from a few, very large vertebrae. See also * List of therapsids This list of therapsids is an attempt to create a comprehensive listing of all genera that have ever been included in the Therapsida excluding mammals and purely vernacular terms. The list includes all commonly accepted genera, but also genera tha ... References The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive Tapinocephalian genera Extinct animals of the United States Permian synapsids Fossil taxa described in 1962 Taxa named by Everett C. Olson {{paleo-Synapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knoxosaurus
''Knoxosaurus'' is an extinct genus of non-mammalian synapsids containing the species ''Knoxosaurus niteckii'' that existed approximately 279.5 to 268 million years ago. It was named by American paleontologist Everett C. Olson in 1962 on the basis of fragmentary fossils from Middle Permian-age deposits in the San Angelo Formation of Texas in the United States. Olson placed ''Knoxosaurus'' in a new infraorder called Eotheriodontia, which he considered a transitional group between the more reptile-like "pelycosaurs" and the more mammal-like therapsids. ''Knoxosaurus'' and Olson's other eotheriodonts were later considered to be undiagnostic remains of basal synapsids, no more closely related to therapsids than are other pelycosaur-grade synapsids. See also * List of therapsids This list of therapsids is an attempt to create a comprehensive listing of all genera that have ever been included in the Therapsida excluding mammals and purely vernacular terms. The list includes all comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorgodon
''Gorgodon'' is an extinct genus of basal synapsids. The genus is monotypic, known only from the type species ''Gorgodon minutus'' from the Early Permian of the southwestern United States. The only known remains of ''Gorgodon'' are two fossils consisting of fragments of the skull. ''Gorgodon'' was described and named by paleontologist Everett C. Olson in 1962 from the San Angelo Formation in Knox County, Texas. Based on what is known of ''Gorgodon''—the squamosal, quadrate, and pterygoid bones of the back of the skull, the maxilla and premaxilla bones that make up the front of the skull, and several teeth—''Gorgodon'' had a relatively large temporal fenestra and a pair large, conical caniniform teeth at the front of the jaw. Other distinguishing features of ''Gorgodon'' include the fused connection between the quadrate and squamosal bones and a long transverse process of the pterygoid (a projection extending from the pterygoid bone on the underside of the skull). Olson clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eosyodon
''Eosyodon'' is a dubious genus of extinct non-mammalian synapsids from the Permian of Texas. Its type and only species is ''Eosyodon hudsoni''. Though it was originally interpreted as an early therapsid, it is probably a member of Sphenacodontidae, the family of synapsids that includes ''Dimetrodon''. ''Eosyodon hudsoni'' was named by Everett C. Olson in 1962 on the basis of fragmentary material from the San Angelo Formation in Texas. The species name honors J. Hudson, a ranch foreman who aided Olson's work. A femur, currently cataloged as FMNH UR 575, was designated the holotype, and skull fragments, partial ribs, and a few other bones were also assigned to the species. Olson interpreted ''Eosyodon'' as a therapsid closely related to ''Syodon'', and assigned both genera to the family Brithopodidae of the infraorder Eotheriodontia. Eotheriodonta was a new taxon defined by Olson in the same paper, to encompass several taxa he regarded as a group of therapsids intermediate betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Driveria
''Driveria'' is an extinct genus of non-mammalian synapsids the Lower Permian of San Angelo Formation, Texas. It is mostly known from several postcranial bones, including the scapula, pelvis, and a few vertebrae and ribs, although a fragment of the skull that might pertain to the upper temporal fenestra is also associated with this species. See also * List of therapsids This list of therapsids is an attempt to create a comprehensive listing of all genera that have ever been included in the Therapsida excluding mammals and purely vernacular terms. The list includes all commonly accepted genera, but also genera tha ... References The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive Tapinocephalian genera Cisuralian synapsids of North America Fossil taxa described in 1962 Taxa named by Everett C. Olson Cisuralian genus first appearances Cisuralian genus extinctions {{Paleo-synapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenacodontid
Sphenacodontidae (Greek: "wedge point tooth family") is an extinct family of small to large, advanced, carnivorous, Late Pennsylvanian to middle Permian pelycosaurs. The most recent one, ''Dimetrodon angelensis'', is from the late Kungurian or early Roadian San Angelo Formation. However, given the notorious incompleteness of the fossil record, a recent study concluded that the Sphenacodontidae may have become extinct as recently as the early Capitanian. Primitive forms were generally small (60 cm to 1 meter), but during the later part of the early Permian these animals grew progressively larger (up to 3 meters or more), to become the top predators of their environments. Sphenacodontid fossils are so far known only from North America and Europe. Characteristics The skull is long, deep and narrow, an adaptation for strong jaw muscles. The front teeth are large and dagger-like, whereas the teeth in the sides and rear of the jaw are much smaller (hence the name of the well-kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimetrodon
''Dimetrodon'' ( or ,) meaning "two measures of teeth,” is an extinct genus of non-mammalian synapsid that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Mya). It is a member of the family Sphenacodontidae. The most prominent feature of ''Dimetrodon'' is the large neural spine sail on its back formed by elongated spines extending from the vertebrae. It walked on four legs and had a tall, curved skull with large teeth of different sizes set along the jaws. Most fossils have been found in the Southwestern United States, the majority coming from a geological deposit called the Red Beds of Texas and Oklahoma. More recently, its fossils have been found in Germany. Over a dozen species have been named since the genus was first erected in 1878. ''Dimetrodon'' is often mistaken for a dinosaur or as a contemporary of dinosaurs in popular culture, but it became extinct some 40 million years before the first appearance of dinosaurs. Reptile-li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimacrodon
''Dimacrodon'' is an extinct genus of non-mammalian synapsid from the latest Early Permian San Angelo Formation of Texas. It is distinguished by toothless, possibly beaked jaw tips, large lower canines and a thin bony crest on top of its head. Previously thought to be an anomodont therapsid related to dicynodonts, it was later found to lack any diagnostic features of anomodonts or even therapsids and instead appears to be a 'pelycosaur'-grade synapsid of uncertain classification. Description Three specimens of ''D. hottoni'' are known, although they only comprise incomplete portions of the lower jaw and skull. The holotype specimen consists of a single partial mandible with teeth. The jaw is long with an unusually broad and deep mandibular symphysis, while the jaw rami are slender (although the additional material from ''D.'' sp. below suggests that the back of the jaws was also deeper). Unusually, the front of the jaw is toothless and has a rough bone texture, possibly support ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotylorhynchus
''Cotylorhynchus'' is an Extinction, extinct genus of herbivorous Caseidae, caseid synapsids that lived during the late Cisuralian, Lower Permian (Kungurian) and possibly the early Guadalupian, Middle Permian (Roadian) in what is now Texas and Oklahoma in the United States. The large number of specimens found make it the best-known caseid. Like all large herbivorous caseids, ''Cotylorhynchus'' had a short snout sloping forward and very large Nostril, external nares. The head was very small compared to the size of the body. The latter was massive, barrel-shaped, and ended with a long tail. The limbs were short and robust. The hands and feet had short, broad fingers with powerful claws. The barrel-shaped body must have housed large intestines, suggesting that the animal had to feed on a large quantity of plants of low nutritional value. Caseids are generally considered to be terrestrial, though a Semiaquatic, semi-aquatic lifestyle has been proposed by some authors. The genus ''Cotyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caseopsis
''Caseopsis'' is an extinct genus of large pelycosaurs that was about long. ''Caseopsis'' lived in the late Early Permian epoch (Kungurian Age), before the pelycosaurs were replaced by the more advanced therapsids (in the next age). It was a lightly built, agile creature. It may have been possible for this species to outpace and escape large predators such as ''Dimetrodon''. See also * List of pelycosaurs This list of pelycosaurs is an attempt to create a comprehensive listing of all genera that have ever been included in the synapsida excluding therapsida and purely vernacular terms. The list includes all commonly accepted genera, but also genera t ... References Kungurian life Caseasaurs Prehistoric synapsid genera Cisuralian synapsids of North America Taxa named by Everett C. Olson Fossil taxa described in 1962 Kungurian genus first appearances Kungurian genus extinctions {{Paleo-synapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
