The
Eothyrididae were a small group of very primitive,
insectivorousAn insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures.Although individually small, insects exist in enormous numbers and make up a very large part of the animal biomass in almost all non-marine environments...
synapsids. Only two genera are known,
EothyrisEothyris is an extinct genus of the family Eothyrididae. It was an insectivorous synapsid. It was closely related to Oedaleops.-Discovery and species:...
and
OedaleopsOedaleops is an extinct genus of the family Eothyrididae. It was closely related to Eothyris. Like Eothyris, it was probably an insectivore.-Discovery and species:...
, both from the early
PermianThe Permian
[The 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...]
of
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
. Their main distinguishing feature is the large
caniniform toothIn mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
in from of the
maxillaThe 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 is sometimes called "upper maxilla", with the mandible being the "lower maxilla"...
.
Eothyridids share with the
CaseidaeThe Caseidae were a widespread group of very primitive herbivorous synapsids, which appeared during the later early Permian and persisted until the late middle Permian. Although ranging in size from 1 to 5 1/2 meters in body length, caseids were surprisingly conservative in their skeletal anatomy...
a number of specialised features associated with the morphology of the snout and external naris and it is likely that they were ancestral to them.
The
Eothyrididae were a small group of very primitive,
insectivorousAn insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures.Although individually small, insects exist in enormous numbers and make up a very large part of the animal biomass in almost all non-marine environments...
synapsids. Only two genera are known,
EothyrisEothyris is an extinct genus of the family Eothyrididae. It was an insectivorous synapsid. It was closely related to Oedaleops.-Discovery and species:...
and
OedaleopsOedaleops is an extinct genus of the family Eothyrididae. It was closely related to Eothyris. Like Eothyris, it was probably an insectivore.-Discovery and species:...
, both from the early
PermianThe Permian
[The 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...]
of
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
. Their main distinguishing feature is the large
caniniform toothIn mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
in from of the
maxillaThe 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 is sometimes called "upper maxilla", with the mandible being the "lower maxilla"...
.
Eothyridids share with the
CaseidaeThe Caseidae were a widespread group of very primitive herbivorous synapsids, which appeared during the later early Permian and persisted until the late middle Permian. Although ranging in size from 1 to 5 1/2 meters in body length, caseids were surprisingly conservative in their skeletal anatomy...
a number of specialised features associated with the morphology of the snout and external naris and it is likely that they were ancestral to them. The two together form the clade
CaseasauriaThe Caseasauria are one of the two main clades of early synapsids, the other being the Eupelycosauria. They are currently known only from the Permian, and include two superficially different families, the small insectivorous or carnivorous Eothyrididae, and the large herbivorous CaseidaeThese two...
.
Until now only the skulls of two species are long were well known,
Eothyris and
Oedaleops, that respectively approximately 6 centimeter that the total length of the animals under 1 meter amounted to. The skulls are characterized through an incidentally wide, flat form and a large skull window. In the waiter jaw, two were enlarged in
Eothyris per jaw half, are eyetooth good teeth, that without counterpart in the lower jaw - in
Oedaleops by far more weakly were stamped these teeth. The remaining teeth are uniform, small and sharpened, assuming that meat or insects are the nourishment of the Eothyrididae. Of the remaining body, no
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
s were found until now.
Both species are only out of the lower
PermianThe Permian
[The 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...]
well known out of
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
. Systematically the Eothyrididae with the
CaseidaeThe Caseidae were a widespread group of very primitive herbivorous synapsids, which appeared during the later early Permian and persisted until the late middle Permian. Although ranging in size from 1 to 5 1/2 meters in body length, caseids were surprisingly conservative in their skeletal anatomy...
form stands the group of the
CaseasauriaThe Caseasauria are one of the two main clades of early synapsids, the other being the Eupelycosauria. They are currently known only from the Permian, and include two superficially different families, the small insectivorous or carnivorous Eothyrididae, and the large herbivorous CaseidaeThese two...
that at the basis of the
SynapsidSynapsids , also known as theropsids , are a class of animals that includes mammals and everything closer to mammals than to other living amniotes. The non-mammalian members are described as mammal-like reptiles in classical systematics, but are referred to as "stem-mammals" or "proto-mammals"...
s and forms that the sister group of the
EupelycosauriaThe Eupelycosauria originally referred to a suborder of Pelycosaurs , but has been redefined to designate a clade of synapsids that includes most pelycosaurs, as well as all therapsids and mammals...
, out of which the Therapsids (the "mammal-like reptiles") evolved.
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