''Glaucosaurus'' is an extinct genus of small

edaphosaurids Edaphosauridae is a family of mostly large (up to 3 meters or more) Late Carboniferous to Early Permian synapsids. Edaphosaur fossils are so far known only from North America and Europe. Characteristics They were the earliest known herbivore, he ...

from the Early

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

. The type species, ''G. megalops'', was named in 1915.S. W. Williston. 1915. New genera of Permian reptiles. ''The American Journal of Science'', series 4 39(233):575-579

Classification

''Glaucosaurus'' is known only from its holotype, a partial

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

and

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 serv ...

. Almost all of the sutures have been obliterated. Nevertheless, there is broad agreement that ''Glaucosaurus'' is not only an edaphosaurid, but a close relative of ''

Edaphosaurus ''Edaphosaurus'' (, meaning "pavement lizard" for dense clusters of teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago, during the Late Carboniferous to ...

'' itself. All of the known sphenacodonts are

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

s except for certain

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...

s. ''Glaucosaurus'' is plainly not a therapsid, e.g. because the lacrimal reaches the

naris A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...

, the septo

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

is large, there are no

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whe ...

s, etc. And it is just as plainly not a carnivore, since it lacks cutting edges on the teeth or canine-like teeth. So, it is very likely to be an edaphosaur. Assuming that this is the case, it is very close to ''Edaphosaurus'', because only ''Glaucosaurus'' and ''Edaphosaurus'' completely lack both canine teeth and a canine buttress, lack the transverse flange of the pterygoid, and have prefrontal with a ventral (descending) process which is expanded toward the middle of the skull, forming an anterior housing for the eyeball. However, ''Glaucosaurus'' differs from any of the known sorts of ''Edaphosaurus'' in have an incredibly long maxilla, and in the equally extreme length of the prefrontal's ventral process.

References

External links

The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive
Edaphosaurids Prehistoric synapsid genera Cisuralian synapsids of North America Taxa named by Samuel Wendell Williston Fossil taxa described in 1915 Cisuralian genus first appearances Cisuralian genus extinctions {{Paleo-synapsid-stub

Classification

See also

References

External links