Eobaataridae is a family of fossil mammals within the order Multituberculata. Remains are known from the Lower Cretaceous of Europe and Asia. They are among the most derived representatives of the informal suborder "Plagiaulacida", and closely related to Cimolodonta. Most eobaatarids are only known from isolated teeth, though several reasonably complete members are known, including Sinobaatar and Jeholbaatar. The body of Sinobaatar is generalised, while Jeholbaatar displays clear adaptations for scansoriality (climbing) due to its elongated digits. Due to the morphology of the cheek teeth, Eobaatar and Jeholbaatar are inferred to be omnivorous, likely feeding on plants and invertebrates.
Castorocauda is an extinct, semi-aquatic, superficially otter-like genus of docodont mammaliaforms with one species, C. lutrasimilis. It is part of the Yanliao Biota, found in the Daohugou Beds of Inner Mongolia, China dating to the Middle to Late Jurassic. It was part of an explosive Middle Jurassic radiation of Mammaliaformes moving into diverse habitats and niches. Its discovery in 2006, along with the discovery of other unusual mammaliaforms, disproves the previous hypothesis of Mammaliaformes remaining evolutionarily stagnant until the extinction of the non-avian dinosaurs.
Docodonta is an order of extinct Mesozoic mammaliaforms. They were among the most common mammaliaforms of their time, persisting from the Middle Jurassic to the Early Cretaceous across the continent of Laurasia. They are distinguished from other early mammaliaforms by their relatively complex molar teeth. Docodont teeth have been described as "pseudotribosphenic": a cusp on the inner half of the upper molar grinds into a basin on the front half of the lower molar, like a mortar-and-pestle. This is a case of convergent evolution with the tribosphenic teeth of therian mammals. There is much uncertainty for how docodont teeth developed from their simpler ancestors. Their closest relatives may have been certain Triassic "symmetrodonts", namely Woutersia, Delsatia, and Tikitherium.
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 considered to be more closely related to marsupials and placentals than to monotremes. They are placed as part of the broader Dryolestida, which also includes the Paurodontidae, and also sometimes the South American-Antarctic Meridiolestida, which are often considered unrelated cladotherians. Dryolestidae taxon is not based on a phylogenetic definition, but instead on the possession of unequal roots for the molars of the lower jaw. Additionally, the clade is distinguished by hypsodonty in lower molars, and uneven labio-lingual height for the alveolar borders of the dentary.
Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods.
Kileskus is a genus of tyrannosauroid dinosaur known from partial remains found in Middle Jurassic Itat Formation of Sharypovsky District, Krasnoyarsk Krai (Russia). Fossils recovered include the holotype maxilla, a premaxilla, a surangular, and a few bones from the hand and foot. Additional remains referred to the species include cervical and caudal vertebrae, as well as a fibula. The skull bones are similar to those of Proceratosaurus. The type species is K. aristotocus. Kileskus was named in 2010 by Averianov and colleagues. Its size has been estimated at 5.2 meters in length and 700 kg in weight.
The Itat Formation is a geologic formation in western Siberia. It was deposited in the Bajocian to Bathonian ages of the Middle Jurassic. Dinosaur remains are among the fossils that have been recovered from the formation, including the proceratosaurid Kileskus, as well as fish, amphibians, mammals and many other vertebrates. The formation is noted for bearing significant coal reserves, with large open pit coal mines extracting lignite from the unit currently in operation.
The Klameliidae is a family of extinct mammals from the Jurassic, belonging to the gobiconodonts. It contains only two species: Ferganodon narynensis and Klamelia zhaopengi.
Sineleutherus is an extinct genus of euharamiyids which existed in Asia during the Jurassic period. The type species is Sineleutherus uyguricus, which was described by Thomas Martin, Alexander O. Averianov and Hans-Ulrich Pfretzschner in 2010; it lived in what is now China during the late Jurassic Qigu Formation. A second species, Sineleutherus issedonicus, was described by A. O. Averianov, A. V. Lopatin and S. A. Krasnolutskii in 2011. It lived in what is now Sharypovsky District during the middle Jurassic ; its fossils were collected from the upper part of the Itat Formation. However, this is now believed to represent several euharamiyid taxa not closey related to Sineleutherus.
Megaconus is an extinct genus of allotherian mammal from the Middle Jurassic Tiaojishan Formation of Inner Mongolia, China. The type and only species, Megaconus mammaliaformis was first described in the journal Nature in 2013. Megaconus is thought to have been a herbivore that lived on the ground, having a similar posture to modern-day armadillos and rock hyraxes. Megaconus was in its initial description found to be member of a group called Haramiyida. A phylogenetic analysis published along its description suggested that haramiyidans originated before the appearance of true mammals, but in contrast, the later description of the haramiyidan Arboroharamiya in the same issue of Nature indicated that haramyidans were true mammals. If haramiyidans are not mammals, Megaconus would be one of the most basal ("primitive") mammaliaforms to possess fur, and an indicator that fur evolved in the ancestors of mammals and not the mammals themselves. However, later studies cast doubt on the euharamiyidan intrepretation, instead finding it to be a basal allotherian mammal.
Polistodon is an extinct genus of tritylodonts from the Bajocian or Callovian of China. It contains one species, P. chuannanensis, which is known from a single skull from the Xiashaximiao Formation. According to one study, it may be a species of the genus Stereognathus.
Stereognathus is an extinct genus of tritylodontid cynodonts from the Middle Jurassic of the United Kingdom. There is a single named species: S. ooliticus, named after the Great Oolite deposits of England. A second species, S. hebridicus, was named after the Hebrides in Scotland, where it was found; it was synonymized with S. ooliticus in 2017.
Xenocretosuchus is an extinct genus of tritylodont therapsids from the Aptian Ilek Formation of Siberia, in the Russian Federation. The type species, X. sibiricus, is known only from dental elements, as is X. kolossovi, described from the Batylykh Formation in 2008. Some authors have treated these species as part of the genus Stereognathus, otherwise known from the Middle Jurassic of Britain, but this is rejected by other authors.
The Ilek Formation is a Lower Cretaceous geologic formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Formation.
Montirictus is an extinct genus of tritylodonts known from the Early Cretaceous Kuwajima Formation of Japan. It was among the latest surviving tritylodontids, and is closely related to the earlier Xenocretosuchus from mainland Asia, and the Jurassic Stereognathus from the UK. It may be a species of the genus Stereognathus, but resolution of its affinities conditions upon the discovery of additional material.
Maiopatagium is an extinct genus of gliding euharamiyids which existed in Asia during the Jurassic period. It possessed a patagium between its limbs and presumably had similar lifestyle to living flying squirrels and colugos. The type species is Maiopatagium furculiferum, which was described from the Tiaojishan Formation by Zhe-Xi Luo in 2017; it lived in what is now the Liaoning region of China during the late Jurassic .Maiopatagium and Vilevolodon, described concurrently, offer clues to the ways various synapsids have taken to the skies over evolutionary time scales. A second species, M. sibiricum, was described from the Bathonian aged Itat Formation in western Siberia, Russia in 2019
Simpsonodon is an extinct genus of docodontan mammaliaform known from the Middle Jurassic of England, Kyrgyzstan and Russia. The type species S. oxfordensis was described from the Kirtlington Mammal Bed and Watton Cliff in the Forest Marble Formation of England. It was named after George Gaylord Simpson, a pioneering mammalologist and contributor to the Modern Evolutionary Synthesis. A second species S. sibiricus is known from the Itat Formation of Russia, and indeterminate species of the genus are also known from the Balabansai Formation in Kyrgyzstan
Itatodon is an extinct genus of primitive mammaliaforms known from the Bathonian aged Itat Formation of Russia. The genus is named after the formation, with the species being named after Leonid Petrovich Tatarinov who described the first docodont from Asia. It is known from a holotype right lower molar and referred isolated right lower molar and fragment of the left lower molar. When it was first described, it was thought to be a docodontan, but one recent phylogenetic studies have assigned it, along with its close relative Paritatodon to Shuotheriidae, while others continue to consider it a docodont.
Kermackodon is an extinct genus of allotherian mammal, known from the Middle Jurassic of England. It combines features of multituberculates with those of euharamyidans. The remains of type species, K. multicuspis were collected from Kirtlington Quarry in Oxford, England, by a team lead from UCL led by Professor Kenneth Kermack after whom the taxon is named, from sediments of the Forest Marble Formation, dating to the Bathonian stage of the Middle Jurassic. The genus and species were named by Percy M. Butler and Jerry Hooker in 2005. The remains comprise a left upper molar (M2), a lower last premolar, initially considered a left but later considered more likely to be right (p4), and an incomplete non-last upper premolar. A second species, K. oxfordensis, from Kirtlington and also sediments of the White Limestone Formation at Woodeaton Quarry was assigned to the genus in 2022, originally placed in the separate genus Eleutherodon. A 2020 study considered it to be more closely related to mutlituberculates than to euharamiyidans, while the 2022 study considered it to be a member of Euharamiyida.
Sibirotherium is an extinct genus of docodont mammaliaform. It is known from only a single named species, Sibirotherium rossicum, known from jaw fragments and teeth found in the Early Cretaceous (Aptian) aged Ilek Formation in western Siberia, alongside Khorotherium also from Siberia, it is one of the youngest docodonts.
