Gymnarthridae is an extinct 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...

 of tuditanomorph

Tuditanomorpha

Tuditanomorpha is a suborder of microsaur lepospondyls. Tuditanomorphs lived from the Late Carboniferous to the Early Permian and are known from North America and Europe. Tuditanomorphs have a similar pattern of bones in the skull roof. Tuditanomorphs display considerable variability, especially in...

 microsaurs. Gymnarthrids are known from Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and existed from the Late Carboniferous through the Early Permian. Remains have been found from the Czech Republic

Czech Republic

The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....

, Nova Scotia

Nova Scotia

Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...

, 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,...

, Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, and Oklahoma

Oklahoma

Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

.

Gymnarthrids are relatively elongate with short limbs. The skulls of gymnarthrids are also small, with a single row of large conical teeth on the margin of the jaw (a feature that distinguishes them from other microsaurs). In some genera, such as Bolterpeton

Bolterpeton

Bolterpeton is an extinct genus of prehistoric amphibian.-See also:* Prehistoric amphibian* List of prehistoric amphibians...

and Cardiocephalus

Cardiocephalus

Cardiocephalus is an extinct genus of leponspondyl amphibian from the Permian period.-External links:*...

, the teeth are labiolingually

Commonly used terms of relationship and comparison in dentistry

There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...

 compressed.

Gymnarthridae was first erected by E. C. Case in 1910 to include the newly described Gymnarthrus. It was placed in a new suborder, Gymnarthria. Case initially considered gymnarthrids to be reptiles, but later recognized them to be amphibians, placing Cardiocephalus in the family. Pariotichus

Pariotichus

Pariotichus is an extinct genus of Permian Lepospondyls.-See also:* Prehistoric amphibian* List of prehistoric amphibians...

was placed within Gymnarthridae by Alfred Romer

Alfred Romer

Alfred Sherwood Romer was an American paleontologist and comparative anatomist and a specialist in vertebrate evolution.-Biography:...

 after having previously been assigned to the basal eureptilia

Eureptilia

Eureptilia is one of the two major clades of the Sauropsida, the other being Anapsida . Eureptilia includes not only all Diapsids, but also a number of primitive Permo-Carboniferous forms previously classified under the Anapsida, in the old order "Cotylosauria".Primitive eureptilians were all...

n family Captorhinidae

Captorhinidae

Captorhinidae is one of the earliest and most basal reptile families.-Description:...

 by Edward Drinker Cope

Edward Drinker Cope

Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...

.