Oxfordian first appearances

Eutheria (from Ancient Greek εὐ- (eú-), meaning "true, well", and θηρίον (thēríon), meaning "beast", and thus, "true beasts"), also called Pan-Placentalia, is the clade consisting of placental mammals and all therian mammals that are more closely related to placentals than to marsupials. Placentalia is the only surviving taxon of Eutherians, and the two are synonymous outside of paleozoology.

thumb|Angelsharks, off the coast of Fuerteventura Angel sharks are sharks belonging to the genus Squatina. They are the only living members of the family Squatinidae and order Squatiniformes. They commonly inhabit sandy seabeds close to in depth.

family of snails

The Cryptobranchoidea are a suborder of salamanders found in Asia, European Russia, and the United States. They are known as primitive salamanders, in contrast to Salamandroidea, the advanced salamanders. It has two living subdivisions, Cryptobranchidae (Asian giant salamanders and hellbenders), and Hynobiidae, commonly known as Asian salamanders.

Dryolestidae is an extinct family of Mesozoic mammals, known from the Middle Jurassic to the Early Cretaceous of the North Hemisphere. The oldest known member, Anthracolestes, is known from the Middle Jurassic Itat Formation of Western Siberia, but most other representatives are known from the Late Jurassic of North America and the Late Jurassic and Early Cretaceous of Europe. Most members are only known from isolated teeth and jaw fragments. Like many other groups of early mammals, they are thought to have been insectivores. They are generally classified in Cladotheria, meaning that they are

Paralligatoridae is an extinct family of neosuchian crocodyliforms that existed during the Jurassic and Cretaceous periods. It includes the genera Paralligator, Brillanceausuchus, Kansajsuchus, Shamosuchus, Doratodon, Scolomastax, Sabresuchus, Rugosuchus, and Batrachomimus.

Aspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae.

thumb|Eutrephoceras dorbignyanum thumb|Eutrephoceras dekayi from the [[Coon Creek Formation]]

Crossognathiformes is an extinct order of ray-finned fish that lived from the Late Jurassic to the Eocene. Its phylogenetic placement is disputed; some authors have recovered it as part of the teleost stem group, while others place it in a basal position within crown group Teleostei. Other placements have found it to be polyphyletic, with Varasichthyidae being stem-group teleosts whereas the other, "true" crossognathiforms are crown-group teleosts within Teleocephala.