Stagonolepis
Encyclopedia
Stagonolepis is an extinct genus
of aetosaur
. It was about 3 metres (9.8 ft) long.
An aetosaur, Stagonolepis was a quadrupedal animal covered in thick armoured scale
s that ran down the length of the its body. A slow-moving browser, it would have used this heavy body armour to repel attacks from contemporary thecodont
carnivores. Stagonolepis had a very small head for its size; it was only 25 centimetres (9.8 in), accounting for less than 10% of the total body length. It had no teeth in the front of its jaw
s, but instead had a beak-like tip that arched upwards. This would have allowed it to uproot plants in a similar manner to a modern pig
. The peg-like teeth at the back of its mouth would have been suitable for chewing tough vegetation, including horsetail
s, fern
s, and the newly evolved cycad
s.
Fossil remains of the animal have been found in Scotland
, South America
, and Poland
. The genus Aetosauroides
from South America
has been considered a junior synonym of Stagonolepis by some paleontologists. Two species of Aetosauroides were named, A. scagliai and A. subsulcatus. In 2002, Andrew B. Heckert and Spencer G. Lucas proposed that smaller specimens of both species belong to Stagonolepis robertsoni, and larger specimens to S. wellesi.
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...
of aetosaur
Aetosaur
Aetosaurs are an extinct order of heavily armoured, medium- to large-sized Late Triassic herbivorous archosaurs. They have small heads, upturned snouts, erect limbs, and a body covered by plate-like scutes. All aetosaurs belong to the family Stagonolepididae...
. It was about 3 metres (9.8 ft) long.
An aetosaur, Stagonolepis was a quadrupedal animal covered in thick armoured scale
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s that ran down the length of the its body. A slow-moving browser, it would have used this heavy body armour to repel attacks from contemporary thecodont
Thecodont
Thecodont , now considered an obsolete term, was formerly used to describe a diverse range of early archosaurs that first appeared in the Latest Permian and flourished until the end of the Triassic period...
carnivores. Stagonolepis had a very small head for its size; it was only 25 centimetres (9.8 in), accounting for less than 10% of the total body length. It had no teeth in the front of its jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
s, but instead had a beak-like tip that arched upwards. This would have allowed it to uproot plants in a similar manner to a modern pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
. The peg-like teeth at the back of its mouth would have been suitable for chewing tough vegetation, including horsetail
Horsetail
Equisetum is the only living genus in the Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.Equisetum is a "living fossil", as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and...
s, fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s, and the newly evolved cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s.
Fossil remains of the animal have been found in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, and Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
. The genus Aetosauroides
Aetosauroides
Aetosauroides is an extinct genus of aetosaur from the Late Triassic of South America. It is one of three aetosaurs known from South America, the others being Neoaetosauroides and Chilenosuchus. Two species have been named: the type species A. scaglia and a second called A...
from South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
has been considered a junior synonym of Stagonolepis by some paleontologists. Two species of Aetosauroides were named, A. scagliai and A. subsulcatus. In 2002, Andrew B. Heckert and Spencer G. Lucas proposed that smaller specimens of both species belong to Stagonolepis robertsoni, and larger specimens to S. wellesi.