''Neosaurus'' ('New Lizard') is an extinct genus of

pelycosaur Pelycosaur ( ) is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term mammal-like reptile was used, and Pelycosauria was considered an order, but this is now thoug ...

-grade

synapsid Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant rept ...

s from the

Late Carboniferous Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * Late (The 77s album), ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudo ...

Early Permian 01 or 01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), ''01'' (Richard Müller album), 2001 * 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...

of the Jura region of

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. It is known only from a partial

maxilla In vertebrates, the maxilla (: maxillae ) 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 two maxil ...

or upper jaw bone and an associated impression of the bone. The teardrop shape of the teeth in the jaw indicate that ''Neosaurus'' belongs to the family

Sphenacodontidae Sphenacodontidae (Greek: "wedge point tooth family") is an extinct family (biology), family of sphenacodontoidea, sphenacodontoid synapsids. Small to large, advanced, carnivore, carnivorous, Late Pennsylvanian to Guadalupian, middle Permian "pelyc ...

, which includes the better-known ''

Dimetrodon ''Dimetrodon'' ( or ; ) is an extinct genus of sphenacodontid synapsid that lived during the Cisuralian (Early Permian) Epoch (geology), epoch of the Permian period, around 295–272 million years ago. With most species measuring long and ...

'' from the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

. The maxilla was first attributed to an early

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the araeosc ...

reptile in 1857, and later a

crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably mor ...

in 1869, before finally being identified as a sphenacodont synapsid in 1899, a classification that still holds today. A species of the

hadrosaur Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

Hypsibema ''Hypsibema'' is an extinct genus of very large basal hadrosauroid dinosaur from the Late Cretaceous (Campanian) of eastern North America. The type species is ''H. crassicauda'', with a potential second species in '' H. missouriensis'' (now gene ...

'', '' H. missouriensis'', is also called '' Neosaurus'', although because the name was already in use, that species was renamed ''

Parrosaurus ''Hypsibema missouriensis'' (; originally ''Neosaurus missouriensis'', first renamed to ''Parrosaurus missouriensis'', also spelled ''Hypsibema missouriense'') is a species of herbivore, plant-eating dinosaur in the genus ''Hypsibema'', and the ...

'' before being reassigned to ''Hypsibema''.

References

Sphenacodontidae Prehistoric synapsid genera Carboniferous synapsids Cisuralian synapsids of Europe Carboniferous France Permian France Fossils of France Fossil taxa described in 1923 Taxa named by Franz Nopcsa von Felső-Szilvás {{Paleo-synapsid-stub