Synapsids are a group of animals that includes mammals and every animal more closely related to mammals than to the other members of the amniote clade, such as reptiles and birds. Unlike other amniotes, they have a temporal fenestra, an opening low in the skull roof behind each eye, leaving a bony arch beneath each; this accounts for their name. Primitive synapsids are usually called pelycosaurs or pelycosaur-grade synapsids. This informal term consists of all synapsids that are not therapsids, a monophyletic, more advanced, mammal-like group. The non-mammalian synapsids were described as mammal-like reptiles in classical systematics, but this misleading terminology is no longer in use as synapsids as a whole are no longer considered reptiles. They are now more correctly referred to as stem mammals or proto-mammals.
Eupelycosauria is a large clade of animals characterized by the unique shape of their skull, encompassing all mammals and their closest extinct relatives. They first appeared 308 million years ago during the Early Pennsylvanian epoch, with the fossils Archaeothyris and perhaps an even earlier genus, Protoclepsydrops, representing just one of the many stages in the evolution of mammals, in contrast to their earlier amniote ancestors.
Suminia is an extinct genus of basal anomodont that lived during the Tatarian age of the late Permian, spanning approximately from 268-252 Ma. Suminia is recognized the youngest non-dicynodont anomodont. Its fossil localities are primarily derived from the Kotel’nich locality of the Kirov region in Russia. However, there have been some isolated specimen found in a few different localities, all from eastern European regions of Russia.
Caseasauria is one of the two main clades of early synapsids, the other being the Eupelycosauria. Caseasaurs are currently known only from the Late Carboniferous and the Permian, and include two superficially different families, the small insectivorous or carnivorous Eothyrididae, and the large, herbivorous, potentially aquatic Caseidae. These two groups share a number of specialised features associated with the morphology of the snout and external naris.
Varanopidae is an extinct family of amniotes that resembled monitor lizards and may have filled a similar niche, hence the name. Typically, they are considered synapsids that evolved from an Archaeothyris-like synapsid in the Late Carboniferous. However, some recent studies have recovered them being taxonomically closer to diapsid reptiles. A varanopid from the latest Middle Permian Pristerognathus Assemblage Zone is the youngest known varanopid and the last member of the "pelycosaur" group of synapsids.
Mycterosaurus is an extinct genus of synapsids belonging to the family Varanopidae. It is classified in the varanopid subfamily Mycterosaurinae. Mycterosaurus is the most primitive member of its family, existing from 290.1 to 272.5 MYA, known to Texas and Oklahoma. It lacks some features that its advanced relatives have.
Varanops is an extinct genus of Early Permian varanopid synapsids known from Texas and Oklahoma of the United States. It was first named by Samuel Wendell Williston in 1911 as a second species of Varanosaurus, Varanosaurus brevirostris. In 1914, Samuel W. Williston reassigned it to its own genus and the type species is Varanops brevirostris.
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose numerous mechanical challenges to animals moving through them and lead to a variety of anatomical, behavioral and ecological consequences as well as variations throughout different species. Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains.
Varanodon is an extinct genus of amniotes from the family Varanopidae. It reached a length of about 1.2 to 1.4 metres. It lived during the early late Permian period.
Nikkasaurus is an extinct genus of therapsids.
Thrausmosaurus is a genus of synapsid pelycosaurs from the extinct family Varanopidae. Like all that resemble members of Varanopidae, Thrausmosaurus most likely resembled the modern monitor lizard and may have had the same lifestyle. The type and only species was described by R. C. Fox in 1962, from three fossilized jaw fragments bearing teeth. The specimens were recovered from the fissure-fill deposits uncovered in a Limestone Quarry, north of Fort Sill, Comanche County, Oklahoma, USA. These deposits are dated to the Kungurian (Leonardian) of the Lower Permian.
Aerosaurus is an extinct genus within Varanopidae, a family of non-mammalian synapsids. It lived between 252-299 million years ago during the Early Permian in North America. The name comes from Latin aes (aeris) “copper” and Greek sauros “lizard,” for El Cobre Canyon in northern New Mexico, where the type fossil was found and the site of former copper mines. Aerosaurus was a small to medium-bodied carnivorous synapsid characterized by its recurved teeth, triangular lateral temporal fenestra, and extended teeth row. Two species are recognized: A. greenleeorum (1937) and A. wellesi (1981).
Mesenosaurus is an extinct genus of amniote. It belongs to the family Varanopidae. This genus includes two species: the type species Mesenosaurus romeri from the middle Permian Mezen River Basin of northern Russia, and Mesenosaurus efremovi from the early Permian (Artinskian) Richards Spur locality. M. romeri’s stratigraphic range is the middle to late Guadalupian while M. efremovi’s stratigraphic range is the Cisuralian.
Watongia is an extinct genus of non-mammalian synapsids from Middle Permian of Oklahoma. Only one species has been described, Watongia meieri, from the Chickasha Formation. It was assigned to family Gorgonopsidae by Olson and to Eotitanosuchia by Carroll. Reisz and collaborators assigned the genus in Varanopidae.
Heleosarus scholtzi is an extinct species of basal synapsids, known as pelycosaurs, in the family of Varanopidae during the middle Permian. At first H. scholtzi was mistakenly classified as a diapsid. Members of this family were carnivorous and had dermal armor, and somewhat resembled monitor lizards. This family was the most geologically long lived, widespread, and diverse group of early amniotes. To date only two fossils have been found in the rocks of South Africa. One of these fossils is an aggregation of five individuals.
Orovenator is an extinct genus of diapsid from Lower Permian deposits of Oklahoma, United States. It is known from two partial skulls from the Richards Spur locality in Oklahoma. The holotype OMNH 74606 consists of a partial skull preserving snout and mandible, and the referred specimen, OMNH 74607, a partial skull preserving the skull roof, vertebrae and palatal elements. It was first named by Robert R. Reisz, Sean P. Modesto and Diane M. Scott in 2011 and the type species is Orovenator mayorum. The generic name means "mountain", oro, in Greek in reference to the Richards Spur locality, which was mountainous during the Permian period and "hunter", venator, in Latin. The specific name honours Bill and Julie May. Orovenator is the oldest and most basal neodiapsid to date.
The Chemnitz petrified forest is a petrified forest in Chemnitz, Germany.
Tambacarnifex is an extinct genus of varanodontine synapsids known from the Early Permian Tambach Formation of Free State of Thuringia, central Germany. It was first named by David S. Berman, Amy C. Henrici, Stuart S. Sumida, Thomas Martens and Valerie Pelletier in 2013 and the type species is Tambacarnifex unguifalcatus.
Ascendonanus is an extinct genus of varanopid amniote from the Early Permian of Germany. It is the earliest specialized arboreal (tree-living) vertebrate currently known and resembled a small lizard, although it was related to mammals. The fossils of Ascendonanus are of special scientific importance because they include remains of skin, scales, scutes, bony ossicles, and body outlines, indicating that some of the oldest relatives of mammals had a scaly "reptilian-type" appearance. The animal was about 40 cm long, with strongly curved claws, short limbs, a slender, elongated trunk, and a long tail. It would have preyed on insects and other small arthropods.
Dendromaia is an extinct genus of varanopid from the Carboniferous of Nova Scotia. It contains a single species, Dendromaia unamakiensis. Dendromaia is the oldest known varanopid, likely the oldest known synapsid, and the only member of the family Varanopidae to be discovered in Nova Scotia. Known from a large partial skeleton preserved with its tail wrapped around a much smaller partial skeleton, Dendromaia may also represent the oldest known occurrence of parental care in the fossil record. While the larger skeleton possessed certain mycterosaurine-like features, the smaller skeleton resembled basal varanopids such as Archaeovenator and Pyozia, creating uncertainty over whether characteristics at the base of Varanopidae have legitimate phylogenetic significance or instead reflect the immaturity of basal varanopid specimens.
