Djadochtatheriidae is a family of fossil mammals within the extinct order Multituberculata. Remains are known from the Upper Cretaceous of Central Asia. These animals lived during the Mesozoic, also known as the "age of the dinosaurs". This family is part of the suborder of Cimolodonta. The taxon Djadochtatheriidae was named by Zofia Kielan-Jaworowska and Jørn Hurum in 1997.
Didolodus is an extinct genus of mammals from Middle Eocene Argentina. It is an ungulate mammal of uncertain affinities, possibly related to Litopterna, though this is uncertain due to the lack of reliable post-cranial remains, and for now remains Meridiungulata incertae sedis. Its remains were found in the Sarmiento Formation of Patagonia.
The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. Although they have often been suggested to have acquired tribosphenic molars independently from those of Tribosphenida, this has been disputed. Fossils of australosphenidans have been found from the Jurassic of Madagascar and Argentina, and Cretaceous of Australia and Argentina. Monotremes have also been considered a part of this group in its original definition and in many subsequent studies, but its relationship with other members has been disputed by some scholars.
Dryolestida is an extinct order of mammals, known from the Jurassic and Cretaceous. They are considered basal 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.
Shuotherium is a fossil mammaliaform known from Middle-Late Jurassic of the Forest Marble Formation of England, and the Shaximiao Formation of Sichuan, China.
The La Colonia Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The Riochican age is a period of geologic time within the Paleocene and Eocene epochs of the Paleogene, used more specifically within the South American land mammal ages (SALMA). It follows the Peligran and precedes the Itaboraian age.
Amphilestidae is a family of Mesozoic mammals, generally regarded as eutriconodonts. They may form a paraphyletic or polyphyletic assemblage, though they share with gobiconodontids their similar tooth occlusion patterns and may be especially closely related to them. They occur from the Middle Jurassic to Cenomanian, and have a distribution across Laurasia.
Umayodus is an extinct genus of "condylarth" mammal from the late Paleocene or the earliest Eocene. It is a didolodontid which lived in what is now Peru. It is known from the holotype LU3-801, an isolated right third molar, which was found in the Muñani Formation of Laguna Umayo, Peru. It was first named by Javier N. Gelfo and Bernard Sigé in 2011 and the type species is Umayodus raimondi.
Reigitherium was a mammal that lived during the Late Cretaceous, in the. Its fossils have been found in the Los Alamitos and the La Colonia Formations of Argentina.
Coloniatherium is a meridiolestid mammal from the Late Cretaceous of Argentina. The single species, Coloniatherium cilinskii, was a large member of the family Mesungulatidae.
Necrolestes is an extinct genus of mammals, which lived during the Early Miocene in what is now Argentine Patagonia. It is the most recent known genus of Meridiolestida, an extinct group of mammals more closely related to therians than to monotremes, which were the dominant mammals in South America during the Late Cretaceous. It contains two species, N. patagonensis and N. mirabilis; the type species N. patagonensis was named by Florentino Ameghino in 1891 based on remains found by his brother, Carlos Ameghino in Patagonia. Fossils of Necrolestes have been found in the Sarmiento and Santa Cruz Formations. Its morphology suggests that it was a digging, subterranean-dwelling mole-like mammal that fed on invertebrates.
Didolodontidae is a possibly paraphyletic family of "condylarth" mammals known from the Paleogene of South America, with most specimens known from Argentina. They were generally small-medium in body size, and had a bunodont dentition. A close relationship with litopterns has been suggested by some studies. They range in age from the early Paleocene (Selandian/Peligran) to late Eocene (Priabonian/Mustersan). The attribution of Salladolodus deuterotheroides from the Late Oligocene of Bolivia to the family is doubtful.
Elaphrocnemus is a genus of extinct bird from the Eocene and Oligocene periods of Europe. Part of Cariamiformes, its closest living relatives are seriemas, though it differs significantly from them, being a better flyer.
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. Meridiolestidans are generally classified within Cladotheria, more closely related to living marsupials and placental mammals (Theria) than to monotremes, barring one study recovering them as the sister taxa to spalacotheriid "symmetrodonts". However, more recent studies have stuck to the cladotherian interpretation. Within Cladotheria, they have often been placed in a group called Dryolestoidea together with Dryolestida, a group of mammals primarily known from the Jurassic and Early Cretaceous of the Northern Hemisphere. However, some analyses have found this group to be paraphyletic, with the meridiolestidans being more or less closely related to therian mammals than dryolestidans are. Meridiolestidans differ from dryolestidans in the absence of a parastylar hook on the molariform teeth and the lack of a Meckelian groove.
Groebertherium is a genus of dryolestoid mammal from the Late Cretaceous Los Alamitos and Allen Formations of Argentina. It is not closely related to other contemporary dryolestoids, all of which are part of the clade Meridiolestida.
Proschismotherium is an extinct genus of ground sloth of the family Megalonychidae, endemic to Argentina during the Early Miocene. It lived from 17.5 mya — 16.3 mya, existing for approximately 1.2 million years. The type, and only, species, P. oppositum, was named in 1902 by Florentino Ameghino based on a single specimen found in the Santacrucian-aged Colpodon Beds of Argentina. Ameghino in 1902 placed Proschismotherium in the Megatheriidae, alongside Hapaloides, which was its sister taxon.
Astigalidae is an extinct family of mammals related to the rodents and lagomorphs. Members of the family are known from the Paleocene and Eocene of China.
Cifellilestes is a genus of early mammaliaform from the Late Jurassic Morrison Formation of North America. The type and only species, C. ciscoensis, was named in 2022 by Brian M. Davis and colleagues, and was found in the Cisco Mammal Quarry of Utah. The generic name of the animal is in honor of Richard Cifelli, combined with the Greek word "lestes", which means thief. The specific name refers to Cisco, Utah, a ghost town close in close proximity to the location where the holotype was found. The genus is known from two specimens, OMNH 80538 & 69352. These specimens represent a right and left skull fragment respectively, both preserving partial palate, snout and postcanine dentition. It belongs to the clade Morganucodonta.
The Salamanca Formation is a geologic formation in the Golfo San Jorge Basin of central Patagonia that yields well-preserved, well-dated fossils from the early Paleocene. Studies of these fossils are providing new data on plant and animal diversity following the end-Cretaceous extinction event.
