Seymouriamorpha
Encyclopedia
Seymouriamorpha were a small but widespread group of reptiliomorphs
. Many seymouriamorphs were terrestrial or semi-aquatic. However, aquatic larva
e bearing external gill
s and grooves from the lateral line
system has been found, making them unquestionably amphibians. The adults were terrestrial. They ranged from lizard
-sized creatures (30 centimeters) to crocodile
-sized 150 centimeter long animals. They were reptile
-like. Because seymouriamorphs are reptiliomorphs, they were the distant relatives of amniote
s, or the relatives of the amniotes's ancestor. Seymouriamorphs form into three main groups, Kotlassiidae, Discosauriscidae
, and Seymouriidae, a group that includes the best known genus
, Seymouria
. The last seymouriamorph became extinct by the end of Permian
.
Cladogram
based on Ruta, Jeffery, & Coates (2003):
Cladogram
based on Klembara (2009) & Klembara (2010):
Reptiliomorpha
Reptiliomorpha refers to an order or subclass of reptile-like amphibians, which gave rise to the amniotes in the Carboniferous. Under phylogenetic nomenclature, the Reptiliomorpha includes their amniote descendants though, even in phylogenetic nomenclature, the name is mostly used when referring to...
. Many seymouriamorphs were terrestrial or semi-aquatic. However, aquatic larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e bearing external gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s and grooves from the lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
system has been found, making them unquestionably amphibians. The adults were terrestrial. They ranged from lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
-sized creatures (30 centimeters) to crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
-sized 150 centimeter long animals. They were reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
-like. Because seymouriamorphs are reptiliomorphs, they were the distant relatives of amniote
Amniote
The amniotes are a group of tetrapods that have a terrestrially adapted egg. They include synapsids and sauropsids , as well as their fossil ancestors. Amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes...
s, or the relatives of the amniotes's ancestor. Seymouriamorphs form into three main groups, Kotlassiidae, Discosauriscidae
Discosauriscidae
Discosauriscidae is a family of reptiliomorphs of the early Permian group Seymouriamorpha....
, and Seymouriidae, a group that includes the best known genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, Seymouria
Seymouria
Seymouria was a reptile-like labyrinthodont from the early Permian of North America and Europe . It was small, only 2 ft long...
. The last seymouriamorph became extinct by the end of Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
.
Taxonomy
- ReptiliomorphaReptiliomorphaReptiliomorpha refers to an order or subclass of reptile-like amphibians, which gave rise to the amniotes in the Carboniferous. Under phylogenetic nomenclature, the Reptiliomorpha includes their amniote descendants though, even in phylogenetic nomenclature, the name is mostly used when referring to...
- Order Seymouriamorpha
- UtegeniaUtegeniaUtegenia is a genus of early tetrapod. It is usually regarded as a basal seymouriamorph, but sometimes included in the Discosauriscidae or as a sister taxon of the latter. Only one species, Utegenia shpinari, found from Kazakhstan, is known. Urumqia, another basal seymouriamorph, from Urumqi,...
- Family Waggoneriidae
- WaggoneriaWaggoneriaWaggoneria is a genus of seymouriamorph reptiliomorph from the Early Permian of Texas. It was named by American paleontologist Everett C. Olson in 1951 on the basis of a holotype fossil that included a weathered skull, lower jaws, vertebrae, and part of the pectoral girdle. The type and only...
- Waggoneria
- Family Kotlassiidae
- Biarmica
- EnosuchusEnosuchusEnosuchus is an extinct genus of Reptiliomorpha....
- KotlassiaKotlassiaKotlassia is an extinct genus of Reptiliomorpha. Fossils of it are found in Russia, in the village of Novinki, close to the city of Kotlas. The name of the genus is derived from the city. The layers in which the fossils were found date from the Late Permian...
- Microphon
- LeptorophaLeptorophaLeptoropha is an extinct genus of aquatic Reptiliomorpha, found in Russia....
- Family Karpinskiosauridae
- Buzulukia
- KarpinskiosaurusKarpinskiosaurusKarpinskiosaurus is an extinct genus of Reptiliomorpha....
- Family DiscosauriscidaeDiscosauriscidaeDiscosauriscidae is a family of reptiliomorphs of the early Permian group Seymouriamorpha....
- AriekanerpetonAriekanerpetonAriekanerpeton is an extinct genus of Seymouriamorpha from the lower Permian. Fossils have been found from Tadzhikistan representing over 900 individuals of various stages of ontogenic development...
- DiscosauriscusDiscosauriscusDiscosauriscus was a small reptiliomorph that lived in Central and Western Europe in the Lower Permian Period. Its best fossils have been found in Boskovice Furrow, in the Czech Republic.-Classification:thumb|180px|left|Discosauriscus...
- MakowskiaMakowskiaMakowskia is an extinct genus of discosauriscid seymouriamorph known from the early Permian of Boskovice Furrow, in the Czech Republic. It was first named by Jozef Klembara in 2009 and the type species is Makowskia laticephala...
- SpinarerpetonSpinarerpetonSpinarerpeton is an extinct genus of discosauriscid seymouriamorph known from the early Permian of Boskovice Furrow, in the Czech Republic. It was first named by Jozef Klembara in 2009 and the type species is Spinarerpeton brevicephalum. A phylogenetic analysis places Spinarerpeton as the sister...
- Ariekanerpeton
- Family Seymouriidae
- Gnorhinosuchus
- Nyctiboetus
- RhinosauriscusRhinosauriscusRhinosauriscus was an extinct genus of the family Seymouriidae of the Seymouriamorpha order. As such, Rhinosauriscus was related to Seymouria and amniotes. Seymouria belonged to the same family as Rhinosauriscus....
- SeymouriaSeymouriaSeymouria was a reptile-like labyrinthodont from the early Permian of North America and Europe . It was small, only 2 ft long...
- Utegenia
Cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
based on Ruta, Jeffery, & Coates (2003):
Cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
based on Klembara (2009) & Klembara (2010):
External links
- Bystrow, A.P. Kotlassia prima Amalitzky. Bulletin of the Geological Society of America, Washington, 1944, v.55, N5, pp.379-416.
- Seymouriamorpha - at Paleos
- Seymouriamorpha at Tree of Life Web ProjectTree of Life Web ProjectThe Tree of Life Web Project is an ongoing Internet project providing information about the diversity and phylogeny of life on Earth. This collaborative peer reviewed project began in 1995, and is written by biologists from around the world....