Lysorophia
Encyclopedia
Lysorophia is an order
of aquatic Carboniferous
and Permian
amphibian
s within the extinct subclass Lepospondyli
. Lysorophians resembled small snake
s, as their bodies are extremely elongate. There is a single family
, the Lysorophidae. Currently there are around five genera
included within Lysorophia.
is lightly built and open, with large orbits
and fenestrae. The intertemporal, supratemporal, postfrontal, and jugal
bones of the skull
have disappeared. The mandible
s are short, and the maxilla
and premaxilla
freely movable.
The torso is very elongate, the limbs diminutive or absent, and the tail short. There are up to 99 pre-sacral (i.e. not including the hips and tail) vertebrae.
Based on morphology of the cranio-vertebral articulation, Lysorophids are usually considered to be related to the Microsauria
, although the pattern of bones of the skull is very different.
in San Juan County
, Utah
and the Mazon Creek fossil beds
in Grundy County, Illinois
. Carboniferous lysorophians are also known from Europe, having been found from England
and Ireland
. Possible remains of a lysorophian have also been found from La Machine
, France
, although they may belong to an aïstopod.
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of aquatic Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
and 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...
amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s within the extinct subclass Lepospondyli
Lepospondyli
Lepospondyli are a group of small but diverse Carboniferous to early Permian tetrapods. Six different groups are known, the Acherontiscidae, Adelospondyli, Aïstopoda, Lysorophia, Microsauria and Nectridea, and between them they include newt-like, eel- or snake-like, and lizard-like forms, along...
. Lysorophians resembled small snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s, as their bodies are extremely elongate. There is a single family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, the Lysorophidae. Currently there are around five genera
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...
included within Lysorophia.
Description
The skullSkull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
is lightly built and open, with large orbits
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
and fenestrae. The intertemporal, supratemporal, postfrontal, and jugal
Jugal
The jugal is a skull bone found in most reptiles, amphibians, and birds. In mammals, the jugal is often called the malar or Zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species....
bones of the skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
have disappeared. The mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
s are short, and the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
and premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
freely movable.
The torso is very elongate, the limbs diminutive or absent, and the tail short. There are up to 99 pre-sacral (i.e. not including the hips and tail) vertebrae.
Based on morphology of the cranio-vertebral articulation, Lysorophids are usually considered to be related to the Microsauria
Microsauria
Microsauria is an extinct order of lepospondyl amphibians from the late Carboniferous and early Permian periods. It is the most diverse and species-rich group of lepospondyls. Recently, Microsauria has been considered paraphyletic, as several other non-microsaur lepospondyl groups such as...
, although the pattern of bones of the skull is very different.
Distribution
Lysorophians are known mainly from the Late Pennsylvanian and Early Permian of North America. In North America, fossils of lysorophians have been found from places such as the Chinle FormationChinle Formation
The Chinle is a geologic formation that is spread across the U.S. states of northern Arizona, Nevada, Utah, western New Mexico, and western Colorado. The Chinle is controversially considered to be synonymous to the Dockum Group in eastern Colorado, eastern New Mexico, southwestern Kansas, the...
in San Juan County
San Juan County, Utah
As of the current census of 2010, there were 14,746 people and 4,505 households. The racial and ethnic composition of the population was 50.4% Native American, 45.8% white, 0.3% Asian, 0.2% African American and 2.3% reporting two or more races...
, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
and the Mazon Creek fossil beds
Mazon Creek fossil beds
The Mazon Creek fossil beds are a conservation found near Morris, in Grundy County, Illinois. The fossil beds are located in ironstone concretions, formed approximately in the mid-Pennsylvanian epoch of the Carboniferous period...
in Grundy County, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
. Carboniferous lysorophians are also known from Europe, having been found from England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
and Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
. Possible remains of a lysorophian have also been found from La Machine
La Machine
La Machine is a commune in the Nièvre department in central France.-Demographics:At the 1999 census, the population was 3735. On 1 January 2004, the estimate was 3649.-Mining city:The mining exploitation marked the history of this town...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, although they may belong to an aïstopod.