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.
Patagonykus is a genus of theropod dinosaur from the Upper Cretaceous of Argentina. This alvarezsauroid was discovered in exposures of the Portezuelo Formation (Turonian-Coniacian) of the Rio Neuquén Subgroup in the Neuquén Basin, Neuquen Province of Patagonia, Argentina. The holotype consists of an incomplete but well-preserved skeleton, lacking a skull, but including many vertebrae, the coracoids, a partial forelimb, pelvic girdle, and hindlimbs. Patagonykus has been classed with the Alvarezsauridae, a family which includes such taxa as the Mongolian Mononykus and the Argentinian Alvarezsaurus. In 2010 Gregory S. Paul estimated its length at 1 meter and its weight at 3.5 kg.
Docodon is an extinct docodont mammaliaform from the Late Jurassic of western North America. It was the first docodont to be named.
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.
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.
Hutegotherium is an extinct genus of tegotheriid docodont known from partial remains found in Middle Jurassic Itat Formation of Krasnoyarsk Krai, Russia. It was first named by Averianov, A. A.; Lopatin, A. V.; Krasnolutskii, S. A.; and Ivantsov, S. V. in 2010 and the type species is Hutegotherium yaomingi.
Juchilestes is an amphidontid mammal genus from the early Cretaceous. It lived in what is now the Beipiao of western Liaoning, eastern China. It is known from the holotype D2607, which consists of three-dimensionally preserved, partial skull with mandibles and some teeth. It was found in 2004 from the Lujiatun Site of the Yixian Formation. It was first named by Chun-Ling Gao, Gregory P. Wilson, Zhe-Xi Luo, A. Murat Maga, Qingjin Meng and Xuri Wang in 2010 and the type species is Juchilestes liaoningensis.
Acinacodus is an extinct genus of amphidontid "eutriconodont" which existed in Shestakovo 1 locality in Western Siberia, Russia during the early Cretaceous period. It was described by A. V. Lopatin, E. N. Maschenko and A. O. Averianov in 2010, and the type species is Acinacodus tagaricus.
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.
Haldanodon is an extinct docodont mammaliaform which lived in the Upper Jurassic. Its fossil remains have been found in Portugal, in the well-known fossil locality of Guimarota, which is in the Alcobaça Formation. It may have been a semi-aquatic burrowing insectivore, similar in habits to desmans and the platypus. Several specimens are known, include a partial skeleton and well-preserved skulls.
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.
Tashkumyrodon is an extinct mammaliaform from the Middle Jurassic (Callovian) Balabansai Formation of Kyrgyzstan It is named after the town of Tash-Kömür, near where the original specimen was found. It belongs to the order Docodonta and is closely related to Sibirotherium and Tegotherium. There is only one species currently known, Tashkumyrodon desideratus.
Borealestes is a genus of docodontan from the Middle Jurassic of Britain, first discovered on the Isle of Skye near the village of Elgol. It was the earliest mammaliaform from the Mesozoic found and named in Scotland. A second species and was later found in other Middle Jurassic sites in England, but is now shown to be a different genus. A new species, B. cuillinensis was named in 2021, also from Skye.
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.
The Batylykh Formation is a geological formation in Yakutia, Russia. It is of an uncertain Early Cretaceous age, probably dating between the Berriasian and the Barremian. It is the oldest unit of the 1,500 metres (4,900 ft) thick Sangar Series within the Vilyuy syneclise. The mudstones, sandstones and shales of the formation were deposited in a fluvial to lacustrine environment.
Dobunnodon its an extinct genus of docodont from the Middle Jurassic (Bathonian) Forest Marble Formation of England, first discovered in Oxfordshire near the village of Kirtlington. The type species, D. mussettae, was originally named as a species of Borealestes in 2003.
Khorotherium is a genus of extinct mammaliaforms. The type and only species, Khorotherium yakutensis, is known from the Lower Cretaceous Batylykh Formation in Western Yakutia, Russia. It belongs to the family Tegotheriidae from the order Docodonta, alongside Sibirotherium from the same region, it is amongst the youngest known docodonts.
Ondogurvel is a genus of alvarezsaurid dinosaur from the Late Cretaceous (Campanian) Barun Goyot Formation in southern Mongolia. The type and only species is O. alifanovi, known from a partial skeleton consisting of fragments of two last dorsal vertebrae, three anterior sacral vertebrae, right ilium, left and right pubis and ischium, articulated right tibia, fibula, metatarsals II and IV, and phalanges IV-1 and IV-2, right carpometacarpus, left and right manual phalanx II-1, right femur, left pedal phalanx II-1, and fragments of unidentified phalanges.
