Cretaceous mammals

Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well as many extinct non-marsupial relatives. It is one of two groups placed in the clade Theria alongside Eutheria, which contains the placentals. Remains of metatherians have been found on all of Earth's continents.

Eomaia ("dawn mother") is a genus of extinct fossil mammals containing the single species Eomaia scansoria, discovered in rocks that were found in the Yixian Formation, Liaoning Province, China, and dated to the Barremian Age of the Lower Cretaceous about . The single fossil specimen of this species is in length and virtually complete. An estimate of the body weight is . It is exceptionally well-preserved for a 125-million-year-old specimen. Although the fossil's skull is squashed flat, its teeth, tiny foot bones, cartilages and even its fur are visible.

Steropodon is a genus of prehistoric platypus-like monotreme, or egg-laying mammal. It contains a single species, Steropodon galmani, that lived about 100.2–96.6 million years ago during the Cretaceous period, from early to middle Cenomanian. It is one of the oldest monotremes discovered, and is one of the oldest Australian mammal discoveries. Several other monotremes are known from the Griman Creek Formation, including Dharragarra, Kollikodon, Opalios, Parvopalus, and Stirtodon.

Sinodelphys is an extinct mammal from the Early Cretaceous, estimated to be 125 million years old. It was discovered and described in 2003 in rocks of the Yixian Formation in Liaoning Province, China, by a team of scientists including Zhe-Xi Luo and John Wible. While initially suggested to be the oldest known metatherian, later studies interpreted it as a eutherian.

Jeholodens is an extinct genus of primitive mammal belonging to the order Eutriconodonta, and which lived in present-day China during the Middle Cretaceous about 125 million years ago.

Periptychidae is a family of Cretaceous–Paleocene placental mammals, known definitively only from North America. The family is part of a radiation of early herbivorous and omnivorous mammals formerly classified in the extinct order "Condylarthra", which may be related to some or all living ungulates (hoofed mammals). Periptychids are distinguished from other "condylarths" by their teeth, which have swollen premolars and unusual vertical enamel ridges. The family includes both large and small genera, with the larger forms having robust skeletons. Known skeletons of periptychids suggest generali

Lavanify is a mammalian genus from the late Cretaceous (probably Maastrichtian, about 71 to 66 million years ago) of Madagascar. The only species, L. miolaka, is known from two isolated teeth, one of which is damaged. The teeth were collected in 1995–1996 and described in 1997. The animal is classified as a member of Gondwanatheria, an enigmatic extinct group with unclear phylogenetic relationships, and within Gondwanatheria as a member of the family Sudamericidae. Lavanify is most closely related to the Indian Bharattherium; the South American Sudamerica and Gondwanatherium are more dist

Kryptobaatar, also known as Gobibaatar or Tugrigbaatar, is an extinct mammalian genus dating from the Upper Cretaceous Period and identified in Central Asia. This animal was a member of the extinct order of Multituberculata within the suborder Cimolodonta, and was a member of the family Djadochtatheriidae. It lived contemporaneously with some of the dinosaurs. Its skull had a length of perhaps 3 cm.

Liaoconodon is an extinct genus of early mammal from the early Cretaceous (early Aptian stage, approximately 120 Ma). It is a eutriconodont which lived in what is now the Jianchang of Liaoning Province, eastern China. It is known from the holotype IVPP V 16051, which consists of nearly complete skeleton and skull. It was found in the Jiufotang Formation (Jehol Biota) near Xiaotaizi, Lamadong. It was first named by Jin Meng, Yuanqing Wang and Chuankui Li in 2011 and the type species is Liaoconodon hui.

Meniscoessus is a genus of extinct multituberculates from the Upper Cretaceous Period that lived in North America.

Ptilodontoidea is a group of extinct mammals from the Northern Hemisphere. They were generally small, somewhat rodent-like creatures of the extinct order Multituberculata.

Sinobaatar is a genus of extinct mammal from the Lower Cretaceous of China. It is categorized within the also extinct order Multituberculata and among these it belongs to the plagiaulacid lineage (a possible infraorder). Sinobaatar was a small herbivore during the Mesozoic era, commonly called "the age of the dinosaurs". The genus was named by Hu Y. and Wang Y. in 2002. Three species have been described.

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids are a paraphyletic grouping, containing all multituberculates that lie outside of the advanced group Cimolodonta. They ranged from the Middle Jurassic Period to the early Late Cretaceous of the Northern Hemisphere. During the Cenomanian, they were replaced by the more advanced cimolodontans.

Deccanolestes is a scansorial, basal Euarchontan from the Late Cretaceous (Maastrichtian) and Paleocene Intertrappean Beds of Andhra Pradesh, India. It may be closely related to Sahnitherium. Deccanolestes has been referred to Palaeoryctidae in the past, but recent evidence has shown that it is either the most basal Euarchontan, as the earliest known Adapisoriculid, or as a stem-afrotherian.

Kennalestes is an extinct genus of insectivorous mammal resembling a shrew that was described in 1968. The type species is K. gobiensis and it was a common mammal in Mongolia during the Cretaceous period, found in both the Bayan Mandahu Formation and Djadochta Formation. It was found in Mongolia during the Campanian, so it may have fallen victim to such predators as Velociraptor, Oviraptor and Archaeornithoides.

Ferugliotheriidae is one of three known families in the order Gondwanatheria, an enigmatic group of extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as members of Multituberculata, a major extinct mammalian order. The best-known representative of Ferugliotheriidae is the genus Ferugliotherium from the Late Cretaceous epoch in Argentina. A second genus, Trapalcotherium, is known from a single tooth, a first lower molariform (molar-like tooth), from a different Late Cretaceous Argentinean locality. Another genus known from a single tooth (in this case, a

Trituberculata is an extinct group of animals existing in the fossil record from about 215 – 85 MYA. It contains the ancestors of Placentalia and Marsupialia; all modern mammals except Monotremata are descended from trituberculates. It is named for the three tubercles (cusps) of the molar teeth (not to be confused with Triconodonta). The clade Trituberculata is not always regarded as a valid one, and it likely does not form a monophyletic group. Instead, some of them may be "true" basal mammals (although not always closest related to each other), while others (such as the symmetrodonts) may fa

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.

Maelestes is a prehistoric shrew-like mammal discovered in 1997 in the Gobi Desert. The animal lived in the late Cretaceous Period, around 71–75 million years ago, and was a contemporary of dinosaurs such as Velociraptor and Oviraptor. According to some scientists, the discovery and analysis of this species suggests that true placental mammals appeared near the time the non-avian dinosaurs became extinct 66 million years ago, not much earlier in the Cretaceous as thought by others. However, the presence of an epipubic bone, among other characteristics, place it as a non-placental eutherian.

Paulchoffatia is a genus of extinct mammal of the Upper Jurassic - Lower Cretaceous. It was a relatively early member of the also extinct order Multituberculata, within the suborder "Plagiaulacida" and family Paulchoffatiidae. It lived in Europe during the "age of the dinosaurs."

Tombaatar is a mammal genus that existed during the Mongolian Upper Cretaceous period. It co-existed with some of the late dinosaurs. This animal was a member of the extinct order Multituberculata, within the suborder Cimolodonta and family Djadochtatheriidae. The genus Tombaatar was named by Rougier G.W., Novacek M. and Dashzeveg D. in 1997.

Ravjaa ishiii is an extinct species of zhelestid mammal from the Late Cretaceous of Mongolia. It is the type and only known species of the genus Ravjaa, which was described in 2025 based on a partial mandible recovered from the Bayanshiree Formation in the Gobi Desert.

fossil mammalian tooth from Madagascar

Spalacotheriidae is a family of extinct mammals belonging to the paraphyletic group 'Symmetrodonta'. They lasted from the Early Cretaceous to the Campanian in North America, Europe, Asia and North Africa.

Kimbetohia is a genus of mammal belonging to the extinct order Multituberculata. It lived from the Upper Cretaceous to the Paleocene period in the United States.

Sunnyodon is a genus of tiny, extinct mammal, probably of the Lower Cretaceous. Found in what is now southern England and Denmark, it was a relatively early member of the extinct order of Multituberculata. It is part of the suborder Plagiaulacida and family Paulchoffatiidae.

Meiconodon is an extinct genus of alticonodontine triconodontid which existed in China during the early Cretaceous period (Aptian/Albian age). It was described by Nao Kusuhashi, Yaoming Hu, Yuanqing Wang, Satoshi Hirasawa and Hiroshige Matsuoka in 2009 and the type species is Meiconodon lii.