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Ophiacodontids
Ophiacodontidae is an extinct family (biology), family of early eupelycosauria, 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 (phylogenetics), basal synapsids, an offshoot of the lineage which includes therapsids and their descendants, the mammals. The group became extinct by the Guadalupian, 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 animal, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eupelycosauria
Eupelycosauria is a large clade of animals characterized by the unique shape of their skull, encompassing all mammals and their closest extinct relatives. They first appeared 308million years ago during the Early Pennsylvanian epoch, with the fossils of ''Echinerpeton'' and perhaps an even earlier genus, ''Protoclepsydrops'', representing just one of the many stages in the evolution of mammals,Kemp. T.S., 1982, ''Mammal-like Reptiles and the Origin of Mammals''. Academic Press, New York in contrast to their earlier amniote ancestors. Eupelycosaurs are synapsids, animals whose skull has a single opening behind the eye. They are distinguished from the Caseasaurian synapsids by having a long, narrow supratemporal bone (instead of one that is as wide as it is long) and a frontal bone with a wider connection to the upper margin of the orbit. Laurin, M. and Reisz, R. R., 1997Autapomorphies of the main clades of synapsids- Tree of Life Web Project The only living descendants of basal e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiacodon
''Ophiacodon'' (meaning "snake tooth") is an extinct genus of synapsid belonging to the family Ophiacodontidae that lived from the Late Carboniferous to the Early Permian in North America and Europe. The genus was named along with its type species ''O. mirus'' by paleontologist Othniel Charles Marsh in 1878 and currently includes five other species. As an ophiacodontid, ''Ophiacodon'' is one of the most basal synapsids and is close to the evolutionary line leading to mammals. Description ''Ophiacodon'' has a large skull with a deep snout. It has the longest skull of any early synapsid, reaching up to in one specimen. The jaws are lined with many small teeth. It was larger than most other tetrapods (four-limbed vertebrates) of its time, ranging from in length and in weight. Specimens of ''Ophiacodon'' vary greatly in size. These differences in size were once used to distinguish species, but are now recognized as ontogenetic variations related to the ages of individuals. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiacodon Mirus
''Ophiacodon'' (meaning "snake tooth") is an extinct genus of synapsid belonging to the family Ophiacodontidae that lived from the Late Carboniferous to the Early Permian in North America and Europe. The genus was named along with its type species ''O. mirus'' by paleontologist Othniel Charles Marsh in 1878 and currently includes five other species. As an ophiacodontid, ''Ophiacodon'' is one of the most basal synapsids and is close to the evolutionary line leading to mammals. Description ''Ophiacodon'' has a large skull with a deep snout. It has the longest skull of any early synapsid, reaching up to in one specimen. The jaws are lined with many small teeth. It was larger than most other tetrapods (four-limbed vertebrates) of its time, ranging from in length and in weight. Specimens of ''Ophiacodon'' vary greatly in size. These differences in size were once used to distinguish species, but are now recognized as ontogenetic variations related to the ages of individuals. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanosaurus
''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 P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereorhachis
''Stereorhachis'' is an extinct genus of non-mammalian synapsids from the Late Carboniferous of France. 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 * Sumida, S. J. & Martin, K. L. M. (eds.). ''Amniote Origins - Completing the Transition to Land''. Academic Press, 1997. 510 p. * Carroll, R. L. ''Vertebrate Paleontology and Evolution''. W. H Freeman Company, 1988. Ophiacodontids Carboniferous synapsids Fossils of France Fossil taxa described in 1880 Prehistoric synapsid genera {{paleo-Synapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereophallodon
''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 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 The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive Ophiacodontids Carboniferous synapsids of North America Taxa named by Alfred Romer Fossil taxa described in 1937 Prehistoric synapsid genera {{paleo-Synapsid-stub ... [...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.Reisz, R., 1972Pelycosaurian reptiles from the middle Pennsylvanian of North America. Harvard University 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. Palaeon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clepsydrops
''Clepsydrops'' is an extinct genus of primitive synapsids from the early Late Carboniferous that was related to ''Archaeothyris''. The name means 'hour-glass appearance' (Greek ''klepsydra'' = "hourglass" + Greek ''ops'' = "eye, face, appearance").http://dinosaurmailinglist.cmnh.org/2016Jun/msg00013.html Synapsida is the group (or clade) that includes mammals, but the term is mainly used to refer to its earliest members. Like many other early terrestrial amniotes, it probably had the diet of insects and smaller animals. It probably laid eggs on land rather than in the water, as most amniote tetrapods did. A paleobiological inference model for the femur suggests a terrestrial lifestyle for ''Clepsydrops'', as for its more recent relative ''Ophiacodon''. This is consistent with its rather thin, compact cortex. Its jaws were slightly more advanced than those of other early amniote tetrapods like '' Paleothyris'' and ''Hylonomus''. See also * List of pelycosaurs * Evolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baldwinonus
''Baldwinonus'' is an extinct genus of basal synapsids from the Early Permian. The type species is ''Baldwinonus trux'', named in 1940 from the Cutler Formation of New Mexico. A second species, ''Baldwinonus dunkardensis'', was named in 1952 from Ohio. ''Baldwinonus'' was first classified in the family Eothyrididae, but the group has since been recognized as a wastebasket taxon for many early synapsids.R. R. Reisz. 1986. Pelycosauria. Handbuch der Paläoherpetologie / Encyclopedia of Paleoherpetology 17A:1-102 More recently, ''Baldwinonus'' has been placed in the family Ophiacodontidae. Its phylogenetic relationship to other early synapsids remains poorly understood because it is only known from a few fragments of bone. Description ''Baldwinonus trux'' is known from a fragment of a right maxilla or upper jaw bone, part of a quadrate bone, and several vertebrae. The maxilla contains 25 tooth sockets, some with teeth. There are sockets for five precaniniform teeth at the front of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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. C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiacodon Retroversus
''Ophiacodon'' (meaning "snake tooth") is an extinct genus of synapsid belonging to the family Ophiacodontidae that lived from the Late Carboniferous to the Early Permian in North America and Europe. The genus was named along with its type species ''O. mirus'' by paleontologist Othniel Charles Marsh in 1878 and currently includes five other species. As an ophiacodontid, ''Ophiacodon'' is one of the most basal synapsids and is close to the evolutionary line leading to mammals. Description ''Ophiacodon'' has a large skull with a deep snout. It has the longest skull of any early synapsid, reaching up to in one specimen. The jaws are lined with many small teeth. It was larger than most other tetrapods (four-limbed vertebrates) of its time, ranging from in length and in weight. Specimens of ''Ophiacodon'' vary greatly in size. These differences in size were once used to distinguish species, but are now recognized as ontogenetic variations related to the ages of individuals. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanids
The Varanidae are a family of lizards in the superfamily Varanoidea within the Anguimorpha group. The family, a group of carnivorous and frugivorous lizards, includes the living genus '' Varanus'' and a number of extinct genera more closely related to ''Varanus'' than to the earless monitor lizard (''Lanthanotus''). ''Varanus'' includes the Komodo dragon (the largest living lizard), crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the earless monitor lizard and chinese crocodile lizard. The oldest members of the family are known from the Late Cretaceous of Mongolia. Taxonomy The Varanidae were defined (using morphological characteristics) by Estes, de Queiroz and Gauthier (1988) as the clade containing the most recent common ancestor of ''Lanthanotus'' and ''Varanus'' and all of its descendants. A similar definition was formulated by Conrad ''et al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
