Seymouria
Encyclopedia
Seymouria was a reptile-like labyrinthodont from the early Permian
of North America
and Europe
(approximately 280 to 270 million years ago). It was small, only 2 ft (60 cm) long. Seymouria was well adapted to life on land, with many reptilian
features--so many, in fact, that it was first thought to be a primitive reptile.
suited reptiles better than amphibian
s and other more primitive tetrapods, but Seymouria had many reptilian features that helped it in this harsh environment. It had long and muscular legs, and may have had dry skin and the ability to conserve water. It may have been able to excrete excess salt from its blood through a gland in its nose, like modern reptiles . All of this meant that Seymouria, unlike amphibians and other early tetrapods, might have lived for extended periods of time away from water. If so, this would have allowed it to move about the landscape in search of insects, small amphibians, and other possible preys, such as the eggs of reptiles.
Male Seymouria had thick skulls that may have been used to batter rivals in mating contests. After mating, the females would have had to return to water to lay their eggs. As in amphibians, the larvae would develop in water, hunting for worms and insects until they were strong enough to live on land. While no larvae are known from Seymouria itself, fossil larvae of its relative Discosauriscus
and other species in the order Seymouriamorpha
have been found, with impressions of external gill structures as in some amphibians.
Fossils of Seymouria were first found in Seymour
, Baylor County
, Texas
(hence the name of the type species, Seymouria baylorensis, or "Baylor County Seymour one"). Over the years, many well preserved fossils have been found in North America and Germany, including the "Tambach
Lovers", two individuals of S. sanjuanensis fossilized lying next to each other (though of course it cannot be determined whether they really were a couple killed during mating). Seymouria agilis (Olson, 1980) that is known from only one specimen (holotype
UCMP 143 277), a nearly complete skeleton
from the Chickasha Formation of Oklahoma
, was reassigned by Michel Laurin
and Robert R. Reisz
as a Macroleter
.
, produced by BBC
. A Seymouria was spying on a Dimetrodon
s nest, the main character of the early Permian scene. It was waiting for the mother Dimetrodon to be caught off guard so it could devour her eggs, but was eventually preyed upon by a male Dimetrodon.
Seymouria was also featured in Evolution: The Game of Intelligent Life
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...
of 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 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...
(approximately 280 to 270 million years ago). It was small, only 2 ft (60 cm) long. Seymouria was well adapted to life on land, with many reptilian
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...
features--so many, in fact, that it was first thought to be a primitive reptile.
Description
The dry climate of the PermianPermian
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...
suited reptiles better than 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 and other more primitive tetrapods, but Seymouria had many reptilian features that helped it in this harsh environment. It had long and muscular legs, and may have had dry skin and the ability to conserve water. It may have been able to excrete excess salt from its blood through a gland in its nose, like modern reptiles . All of this meant that Seymouria, unlike amphibians and other early tetrapods, might have lived for extended periods of time away from water. If so, this would have allowed it to move about the landscape in search of insects, small amphibians, and other possible preys, such as the eggs of reptiles.
Discosauriscus
Discosauriscus 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...
and other species in the order Seymouriamorpha
Seymouriamorpha
Seymouriamorpha were a small but widespread group of reptiliomorphs. Many seymouriamorphs were terrestrial or semi-aquatic. However, aquatic larvae bearing external gills and grooves from the lateral line system has been found, making them unquestionably amphibians. The adults were terrestrial...
have been found, with impressions of external gill structures as in some amphibians.
Fossils of Seymouria were first found in Seymour
Seymour, Texas
Seymour is a city in and the county seat of Baylor County, Texas, United States. The population was 2,740 as of the 2010 Census.-Geography:Seymour is located at ....
, Baylor County
Baylor County, Texas
As of the census of 2000, there were 4,093 people, 1,791 households, and 1,156 families residing in the county. The population density was 5 people per square mile . There were 2,820 housing units at an average density of 3 per square mile...
, 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...
(hence the name of the type species, Seymouria baylorensis, or "Baylor County Seymour one"). Over the years, many well preserved fossils have been found in North America and Germany, including the "Tambach
Tambach-Dietharz
Tambach-Dietharz is a town in the district of Gotha, in Thuringia, Germany. It is situated in the Thuringian Forest, 19 km south of Gotha.- Places of interest :...
Lovers", two individuals of S. sanjuanensis fossilized lying next to each other (though of course it cannot be determined whether they really were a couple killed during mating). Seymouria agilis (Olson, 1980) that is known from only one specimen (holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
UCMP 143 277), a nearly complete skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
from the Chickasha Formation of 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...
, was reassigned by Michel Laurin
Michel Laurin
Michel Laurin is a Canadian vertebrate paleontologist specialising in the origin and phylogeny of tetrapods, comparative biology and paleobiology. As an undergraduate he worked in the laboratory of Robert L. Carroll, and took his doctor thesis on the osteology of seymouriamorphs under Robert R....
and Robert R. Reisz
Robert R. Reisz
Robert Rafael Reisz is a Canadian paleontologist and specialist in the study of early amniote and tetrapod evolution.Robert Reisz was born August 27, 1947, in Oradea, Romania. He received his B.Sc. , M.Sc. and Ph.D. from McGill University as Robert L. Carroll’s first doctoral graduate...
as a Macroleter
Macroleter
Macroleter is an extinct genus of parareptile which existed in Oklahoma and Russia during the upper Permian period. It was first named by paleontologists Tverdochlebova and Ivachnenko in 1984. The type species is Macroleter poezicus from Upper Permian of Russia...
.
In popular culture
Seymouria was featured in the television series Walking with MonstersWalking with Monsters
Walking with Monsters is a three-part British documentary film series about life in the Paleozoic, bringing to life extinct arthropods, fish, amphibians, synapsids, and reptiles...
, produced by BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
. A Seymouria was spying on a Dimetrodon
Dimetrodon
Dimetrodon was a predatory synapsid genus that flourished during the Permian period, living between 280–265 million years ago ....
s nest, the main character of the early Permian scene. It was waiting for the mother Dimetrodon to be caught off guard so it could devour her eggs, but was eventually preyed upon by a male Dimetrodon.
Seymouria was also featured in Evolution: The Game of Intelligent Life
Evolution: The Game of Intelligent Life
Evolution: The Game of Intelligent Life, also known as Genetic Evolution: The Race for Intelligent Life in Germany and Evolução: O Jogo da Vida in Brazil, is a life simulation & real-time strategy computer game that allows players to experience, guide, and control evolution from an isometric view...