Multituberculata is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, and reached a peak diversity during the Late Cretaceous and Paleocene. They eventually declined from the mid Paleocene onwards, disappearing from the known fossil record in the late Eocene. They are the most diverse order of Mesozoic mammals with more than 200 species known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as crown mammals outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and Monotremata—but usually as closer to Theria than to monotremes. They are considered to be closely related to Euharamiyida and Gondwanatheria as part of Allotheria.
Volaticotherium antiquum is an extinct, gliding, insectivorous mammal that lived in Asia during the Jurassic period, around 164 mya. It is the only member of the genus Volaticotherium.
Eutriconodonta is an order of early mammals. Eutriconodonts existed in Asia, Africa, Europe, North and South America during the Jurassic and the Cretaceous periods. The order was named by Kermack et al. in 1973 as a replacement name for the paraphyletic Triconodonta.
Pseudotribos is an extinct genus of mammal that lived in Northern China during the Middle Jurassic some 165 million years ago, possibly more closely related to monotremes than to theria, although other studies indicate that these shuotheres are closer to therians than to monotremes. The only known specimen was found in the Daohugou Bed in Inner Mongolia.
Gobiconodon is an extinct genus of carnivorous mammal from the Middle Jurassic to Early Cretaceous. It weighed 5.4 kilograms (12 lb), had a skull of 10 cm (3.9 in) in length, and had 35 cm (14 in) in presacral body length. It was one of the largest mammals known from the Mesozoic. Like other gobiconodontids, it possesses several speciations towards carnivory, such as shearing molar teeth, large canine-like incisors and powerful jaw and forelimb musculature, indicating that it probably fed on vertebrate prey; rather uniquely among predatory mammals and other eutriconodonts, the lower canines were vestigial, with the first lower incisor pair having become massive and canine-like. Like the larger Repenomamus there might be some evidence of scavenging.
Dryolestida is an extinct order of mammals; most of the members are mostly known from the Jurassic and Cretaceous. They are considered members of the clade Cladotheria, close to the ancestry of therian mammals. It is also believed that they developed a fully mammalian jaw and also had the three middle ear bones. Most members of the group, as with most Mesozoic mammals, are only known from fragmentary tooth and jaw remains.
Shuotheriidae is a small family of Jurassic mammals whose remains are found in China, England and possibly Russia. They have been proposed to be close relatives of Australosphenida, the group that contains living monotremes, together forming the clade Yinotheria. However, some studies suggest shuotheres are closer to therians than to monotremes. The Shuotheriidae have been proposed as the sister group of the Gondwanian clade Henosferida and the Monotremata, which are the monotremes.
Henosferidae is an extinct family of Australosphenida, native to Gondwana during the Middle Jurassic. Its defined as a clade including the most recent common ancestor of Henosferus and Asfaltomylos and all its descendants.
Triconolestes is an extinct genus of Late Jurassic eutriconodont mammal from the Morrison Formation, present in stratigraphic zones 4. Known from only a single molar, it is a small mammal typically considered an amphilestid. However, it has also been compared to Argentoconodon, which has been considered a volaticothere related to gliding mammals such as Volaticotherium and Ichthyoconodon.
Triconodontidae is an extinct family of small, carnivorous mammals belonging to the order Eutriconodonta, endemic to what would become Asia, Europe, North America and probably also Africa and South America during the Jurassic through Cretaceous periods at least from 190–70.6 mya.
The Cañadón Asfalto Formation is a Lower Jurassic to Late Jurassic geologic formation, from the Jurassic period of the Mesozoic Era. Its age is controversial, uranium-lead dating of the volcanic tuff beds having given various different ages. A Recent work suggested that the base of the formation was formed around 171 Ma, during the upper Aalenian, while the main age for the Lower Las Chacritas Member being around 168 Ma, during the Bajocian, Bathonian and Callovian While the overlying Puesto Almada Member seems to be around 158 ma, or Oxfordian age, that changed thanks to the discovery of zircons near the location of discovery of Bagualia, allowing a precise age of Las Charcitas Member as Middle-Late Toarcian, 178-179 million years, and a later study constrained the age of the formation as Middle Toarcian-Lower Bajocian, being contemporaneous to the Chon Aike volcanic activity, being a local equivalent to Antarctica's Mawson Formation.
The Amphidontidae are a family of extinct mammals from the Early Cretaceous, belonging to the triconodonts. It contains most of the species previously belonged to Amphilestidae.
Drescheratherium is an extinct genus of mammal from the Late Jurassic (Kimmeridgian) Camadas de Guimarota of Leiria, Portugal. It is represented by fairly complete upper jaws with teeth. It bears elongated upper canines, though not to the extent another dryolestoid, Cronopio, does.
Cronopio is an extinct genus of small insectivorous mammal known from the early Late Cretaceous of the Río Negro region in Argentina. Its only species is Cronopio dentiacutus. It belongs to the Meridiolestida, an extinct group of mammals widespread in South America during the Late Cretaceous, which are more closely related to modern marsupials and placental mammals than to monotremes.
Gobiconodonta is an order of extinct mammals known from the Early Jurassic to early Late Cretaceous. They are generally held to be part of Eutriconodonta.
Argentoconodon is an extinct genus of theriimorph mammal from the Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Patagonia. When originally described, it was known only from a single molariform tooth, which possessed a combination of primitive and derived features. The tooth is currently held in the Museo Paleontológico Egidio Feruglio, where it was given the specimen number MPEF-PV 1877. New material described in 2011 show that Argentoconodon was similar to Ichthyoconodon, Jugulator and Volaticotherium within the family Triconodontidae, and possibly also Triconolestes.
Ichthyoconodon is an extinct genus of eutriconodont mammal from the Lower Cretaceous of Morocco. It is notable for having been found in a unique marine location, and the shape of its teeth suggests an unusual, potentially fish-eating ecological niche. Analysis suggests it is part of a group of gliding mammals that includes Volaticotherium.
Jugulator is an extinct genus of mammals from the Cretaceous of North America. It contains one species, Jugulator amplissimus. A eutriconodont, it is known from the Cedar Mountain Formation, and is both a large sized and possibly ecologically specialised taxon, showcasing the diversity of mammals in the Mesozoic.
Meridiolestida is an extinct clade of mammals known from the Cretaceous and Cenozoic of South America and possibly Antarctica. They represented the dominant group of mammals in South America during the Late Cretaceous. Meridiolestidans were morphologically diverse, containing both small insectivores such as the "sabretooth-squirrel" Cronopio, as well as the clade Mesungulatoidea/Mesungulatomorpha, which ranged in size from the shrew-sized Reigitherium to the dog-sized Peligrotherium. Mesungulatoideans had highly modified dentition with bunodont teeth, and were likely herbivores/omnivores.
Condorodon is a genus of extinct mammals from the Lower Jurassic Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Patagonia, Argentina. The type species is C. spanios, described by Gaetano and Rougier in 2012.
