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Mesenosaurus And Varanodon
''Mesenosaurus'' is an extinct genus of amniote. It belongs 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, and named it after its roots with the (literal translation is “lizard from Mezen”). ''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 of fossil evidence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an 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 evolutionary narratives about ance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanosaurus Acutirostris
''Varanosaurus'' ('monitor lizard') is an extinct genus of early pelycosaur synapsid that lived during the Kungurian. 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 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 Further reading *Benes, Josef. Prehistoric Animals and Plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeothyris Florensis
''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 canines, suggesting that it was a carnivore. Archaeothyris' legs were articulated laterally at its pelvis and shoulders, which gave it a sprawling stance. The first toe is smaller than the second. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiacodontidae
Ophiacodontidae is an extinct family of early eupelycosaurs 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 Middle Permian, 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 st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenacodontia
Sphenacodontia is a stem-based clade of derived synapsids. It was defined by Amson and Laurin (2011) as "the largest clade that includes ''Haptodus baylei'', ''Haptodus garnettensis'' and '' Sphenacodon ferox'', but not ''Edaphosaurus pogonias''". They first appear during the Late Pennsylvanian (Upper Carboniferous) epoch. From the end of the Carboniferous to the end of the Permian, most of them remained large, with only some secondarily becoming small in size. Basal Sphenacodontia constitute a transitional evolutionary series from early pelycosaurs to ancestral therapsids (which in turn were the ancestors of more advanced forms and finally the mammals). One might say that the sphenacodontians are proto-therapsids (even though there is almost a 30-million-years gap between the separation of the ancestors of therapsids from other sphenacodontians and the first appearance of therapsids in the fossil record). Characteristics The defining characteristics include a thickening of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edaphosauridae
Edaphosauridae is a family of mostly large (up to 3 meters or more) Late Carboniferous to Early Permian synapsids. Edaphosaur fossils are so far known only from North America and Europe. Characteristics They were the earliest known herbivorous amniotes and, along with the Diadectidae, the earliest known herbivorous tetrapods. The head is small in relation to the bulky body, and there is a tall sail along the back, which may have functioned as a thermoregulatory device. Classification The interrelationships of Edaphosauridae was investigated in details by David M. Mazierski and Robert R. Reisz (2010). The cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ... below is modified after their phylogenetic analysis. Below is a cladogram modified from the analysis of Benson (in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ianthodon Schultzei
''Ianthodon'' is an extinct genus of basal haptodontiform synapsids from the Late Carboniferous about 304 million years ago. The taxon was discovered and named by Kissel & Reisz in 2004.Kissel, R. A. & Reisz, R. R. ''Synapsid fauna of the Upper Pennsylvanian Rock Lake Shale near Garnett, Kansas and the diversity pattern of early amniotes''. In G. Arratia, M. V. H. Wilson & R. Cloutier (eds.). ''Recent Advances in the Origin and Early Radiation of Vertebrates''. Verlag Dr. Friedrich Pfeil, 2004. The only species in the taxon, ''Ianthodon schultzei'', was found by separating it from a block that also contained the remains of ''Petrolacosaurus'' and ''Haptodus''. The evolutionary significance of the taxon wasn't realized until a publication in 2015. The fossil of this organism was discovered in Garnett, Kansas. Description ''Ianthodon'' was first named by Kissel & Reisz in 2004, and a more detailed specimen was reevaluated in 2014. This single juvenile skeleton with delicate bones ... [...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, herbivorous Caseidae. These two groups share a number of specialised features associated with the morphology of the snout and external naris. The ancestor of caseasaurs can be traced back to an insect eating or an omnivorous reptile-like synapsid from the 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). Description Among the most conspicuous charact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protorothyris Archeri
''Protorothyris'' is an extinct genus of Early Permian protorothyridid known from Texas and West Virginia of the United States. It was first named by Llewellyn Ivor Price in 1937 and the type species is ''Protorothyris archeri''. ''P. archeri'' is known from the holotype MCZ 1532, a three-dimensionally preserved skull and from the referred specimens, which come from four additional individuals, MCZ 2147-2150. All specimens were collected in the Cottonwood Creek site, from the Archer City Formation, Texas, dating to the Asselian stage of the Cisuralian epoch, about 299–294.6 million years ago. A second species, ''P. morani'', was first named by Alfred Sherwood Romer in 1952 with its own generic name, ''Melanothyris''. In 1973, J. Clark and Robert L. Carroll recombined ''P. morani'' as a ''Protorothyris'' species. It is known from the holotype CM 8617, a three-dimensionally preserved skull. It was collected in the Blacksville site, from the Washington Formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captorhinus
''Captorhinus'' (from el, καπτō , 'to gulp down' and el, ῥῑνός , 'nose') is an extinct genus of captorhinid reptiles that lived during the Permian period. Its remains are known from Oklahoma, Texas, Europe, India, the Pedra de Fogo Formation, Parnaíba Basin, Brazil and the Madumabisa Mudstone, Zambia. Description While there are several forms of ''Captorhinus'', there are three main species that are the best known. The previously mentioned ''Captorhinus aguti'' is the type species of ''Captorhinus'', but there is also a fair amount of material collected on ''Captorhinus magnus'' and ''Captorhinus laticeps''. The most distinguishable trait of ''Captorhinus'' is its namesake: the hooking of the snout from prominent ventral angulation of the premaxillary process. Other notable characteristics include the dorsally positioned alary process of the jugal on the medial surface and flushed with the orbital margin, the retroarticular process longer anteroposteriorly th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
