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Archaeothyris
''Archaeothyris'' is an extinct genus of ophiacodontid synapsid that lived during the Late Carboniferous and is known from Nova Scotia. Dated to 306 million years ago, ''Archaeothyris'', along with a more poorly known synapsid called ''Echinerpeton'', are the oldest undisputed synapsids known. The name means ''ancient window'' (Greek), and refers to the opening in the skull, the temporal fenestra, which indicates this is an early synapsid. ''Protoclepsydrops'' also from Nova Scotia is slightly older but is known by very fragmentary materials. Description ''Archaeothyris'' was more advanced than the early sauropsids, having strong jaws that could open wider than those of the early reptiles. While its sharp teeth were all of the same size & shape, it did possess a pair of enlarged canine (tooth), canines, suggesting that it was a carnivore. ''Archaeothyriss legs were articulated laterally at its pelvis and shoulders, which gave it a sprawling stance. The first toe is smaller than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiacodontidae
Ophiacodontidae is an extinct family of early synapsids from the Carboniferous and Permian. '' Archaeothyris'', and '' Clepsydrops'' were among the earliest ophiacodontids, appearing in the Late Carboniferous. Ophiacodontids are among the most basal synapsids, an offshoot of the lineage which includes therapsids and their descendants, the mammals. The group became extinct by the Kungurian or the Roadian, replaced by anomodonts, theriodonts, and the diapsid reptiles. Characteristics The lifestyle of ophiacodonts has long been controversial. Some studies suggested that they were semi-aquatic, and some even suggested a fairly aquatic lifestyle, but a recent study based on a quantitative inference model suggested that both '' Clepsydrops'' and '' Ophiacodon'' were terrestrial. Vertebral morphometric data also support, though ambiguously, a rather terrestrial lifestyle for '' Ophiacodon'', which could reach a length of . '' Archaeothyris'' may also have been terrestrial, but no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiacodontid
Ophiacodontidae is an extinct family of early synapsids from the Carboniferous and Permian. ''Archaeothyris'', and ''Clepsydrops'' were among the earliest ophiacodontids, appearing in the Late Carboniferous. Ophiacodontids are among the most basal synapsids, an offshoot of the lineage which includes therapsids and their descendants, the mammals. The group became extinct by the Kungurian or the Roadian, replaced by anomodonts, theriodonts, and the diapsid reptiles. Characteristics The lifestyle of ophiacodonts has long been controversial. Some studies suggested that they were semi-aquatic, and some even suggested a fairly aquatic lifestyle, but a recent study based on a quantitative inference model suggested that both ''Clepsydrops'' and ''Ophiacodon'' were terrestrial. Vertebral morphometric data also support, though ambiguously, a rather terrestrial lifestyle for ''Ophiacodon'', which could reach a length of . ''Archaeothyris'' may also have been terrestrial, but no detailed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapsid
Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant reptiles and therefore, birds). Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye socket, leaving a zygomatic arch, bony arch beneath each; this accounts for the name "synapsid". The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals. The basal (phylogenetics), basal amniotes (reptiliomorphs) from which synapsids evolved were historically simply called "reptiles". Therefore, stem group synapsids were then described as mammal-like reptiles in classical systematics, and non-therapsid synapsids were also referred to as pelyco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapsida
Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant reptiles and therefore, birds). Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye socket, leaving a bony arch beneath each; this accounts for the name "synapsid". The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals. The basal amniotes ( reptiliomorphs) from which synapsids evolved were historically simply called "reptiles". Therefore, stem group synapsids were then described as mammal-like reptiles in classical systematics, and non- therapsid synapsids were also referred to as pelycosaurs or pelycosaur- grade syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amniota
Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibious stem tetrapod ancestors during the Carboniferous period. Amniota is defined as the smallest crown clade containing humans, the Greek tortoise, and the Nile crocodile. Amniotes are distinguished from the other living tetrapod clade — the non-amniote lissamphibians (frogs/ toads, salamanders/newts and caecilians) — by: the development of three extraembryonic membranes ( amnion for embryonic protection, chorion for gas exchange, and allantois for metabolic waste disposal or storage); thicker and keratinized skin; costal respiration (breathing by expanding/constricting the rib cage); the presence of adrenocortical and chromaffin tissues as a discrete pair of glands near their kidneys; more complex kidneys; the presence of an astragalus for better extremity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinerpeton
''Echinerpeton'' is an extinct genus of synapsid, including the single species ''Echinerpeton intermedium'' from the Late Carboniferous of Nova Scotia, Canada. The name means 'spiny lizard' (Greek). Along with its contemporary ''Archaeothyris'', ''Echinerpeton'' is the oldest known synapsid, having lived around 308 million years ago. It is known from six small, fragmentary fossils, which were found in an outcrop of the Morien Group near the town of Florence. The most complete specimen preserves articulated vertebrae with high neural spines, indicating that ''Echinerpeton'' was a sail-backed synapsid like the better known ''Dimetrodon'', ''Sphenacodon'', and ''Edaphosaurus''. However, the relationship of ''Echinerpeton'' to these other forms is unclear, and its phylogenetic placement among basal synapsids remains uncertain. Description ''Echinerpeton'' is known from six specimens, five housed in the Museum of Comparative Zoology and a sixth in the Redpath Museum: the holotype MCZ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoclepsydrops
''Protoclepsydrops'' is an extinct genus of early synapsids, found in Joggins, Nova Scotia. The name means 'first ''Clepsydrops, and refers to it being the predecessor of the other early synapsid ''Clepsydrops''. Description Like ''Archaeothyris'', ''Protoclepsydrops'' resembled a modern lizard in superficial appearance. However, ''Protoclepsydrops'' had primitive vertebrae with tiny neural processes typical of their amniote ancestors. ''Protoclepsydrops'' is known from a few vertebrae and some humeri. Classification Its skeletal remains indicate that it may have been more closely related to synapsids than to sauropsids, making it a possible stem-mammal. If so, it is the oldest synapsid known, though its status is unconfirmed because its remains are too fragmentary. ''Protoclepsydrops'' lived slightly earlier than ''Archaeothyris''.Benton M.J. and Donoghue P.C.J. 2006. Palaeontological evidence to date the tree of life. ''Molecular biology and evolution''. 24(1): 26–53/ref> ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanosaurus Acutirostris
''Varanosaurus'' ('monitor lizard') is an extinct genus of early ophiacodontid synapsid that lived during the Artinskian and Kungurian ages of the Permian.R. R. Reisz. 1986. Pelycosauria. ''Handbuch der Paläoherpetologie / Encyclopedia of Paleoherpetology'' 17A:1-102 Description As its name implies, ''Varanosaurus'' may have looked superficially similar to present-day monitor lizards, though not related at all. ''Varanosaurus'' had a flattened, elongated skull and a pointed snout with a row of sharp teeth, including two pairs of conspicuous pseudocanines, implying that it was an active predator. ''Varanosaurus'' probably lived in swamps, competing with the larger ''Ophiacodon'' for food. Classification Below is a cladogram modified from the analysis of Benson (2012): See also * List of pelycosaurs This list of pelycosaurs is an attempt to create a comprehensive listing of all Genus, genera that have ever been included in the synapsida excluding therapsida and purely v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caseasauria
Caseasauria is one of the two main clades of early synapsids, the other being the Eupelycosauria. Caseasaurs are currently known only from the Late Carboniferous and the Permian, and include two superficially different families, the small insectivorous or carnivorous Eothyrididae, and the large, herbivory, herbivorous Caseidae. These two groups share a number of specialised features associated with the morphology of the snout and external nares, naris. The ancestor of caseasaurs can be traced back to an insect eating or an omnivorous reptile-like synapsid from the Pennsylvanian (geology), Pennsylvanian time of the Carboniferous, possibly resembling ''Archaeothyris'', the earliest known synapsid. The caseasaurs were abundant during the later part of the Early Permian, but by the Middle Permian caseasaur diversity declined because the group was outcompeted by the more successful therapsids. The last caseasaurs became extinct at the end of the Guadelupian (Middle Permian). Descript ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hylonomus
''Hylonomus'' (; ''hylo-'' "forest" + ''nomos'' "dweller") is an extinct genus of reptile that lived during the Bashkirian stage of the Late Carboniferous. It is the earliest known crown group amniote and the oldest known unquestionable reptile, with the only known species being ''Hylonomus lyelli''. Despite being amongst the oldest known reptiles, it is not the most primitive member of the group, being a eureptile more derived than either parareptiles or captorhinids. Discovery and naming ''Hylonomus lyelli'' was first described by John William Dawson in 1860. The species' name was given in honor of Dawson's teacher, the geologist Sir Charles Lyell. While it has traditionally been included in the group Protorothyrididae, it has since been recovered outside this group. Formerly assigned species Dawson also attributed two other species ''H. aciedentatus'' and ''H. wymani'' when he described ''H. lyelli'' in 1860, and later described two more species ''H. multidens'' and ''H. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereophallodon Ciscoensis
''Stereophallodon'' is an extinct genus of non-mammalian synapsids. See also * List of pelycosaurs This list of pelycosaurs is an attempt to create a comprehensive listing of all Genus, genera that have ever been included in the synapsida excluding therapsida and purely vernacular terms. The list includes all commonly accepted genera, but also g ... References The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive Bibliography *A. S. Romer. 1937. New genera and species of pelycosaurian reptiles. ''Proceedings of the New England Zoölogical Club'' 16:89-95 *Brinkman, D. & Eberth, D.A., 1986, The anatomy and relationships of ''Stereophallodon'' and ''Baldwinonus'' (Reptilia, Pelycosauria): ''Breviora'', no. 485, p. 34. Ophiacodontidae Carboniferous synapsids of North America Taxa named by Alfred Romer Fossil taxa described in 1937 {{paleo-synapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
