Echidnas, sometimes known as spiny anteaters, are quill-covered monotremes belonging to the family Tachyglossidae, living in Australia and New Guinea. The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the only surviving members of the order Monotremata. The diet of some species consists of ants and termites, but they are not closely related to the American true anteaters or to hedgehogs. Their young are called puggles.
Monotrematum sudamericanum is an extinct monotreme species from the Paleocene (Peligran) Salamanca Formation in Patagonia, Argentina. It is one of only two monotremes found outside Oceania.
The Ornithorhynchidae are one of the two extant families in the order Monotremata, and contain the platypus and its extinct relatives. The other family is the Tachyglossidae, or echidnas.
Kollikodon is an extinct species of mammal, considered to be an early monotreme. It is known only from an opalised dentary fragment, with one premolar and two molars in situ, as well as a referred maxillary fragment containing the last premolar and all four molars. The fossils were found in the Griman Creek Formation at Lightning Ridge, New South Wales, Australia. Kollikodon lived in the Late Cretaceous period, during the Cenomanian age. Several other monotremes are known from the Griman Creek Formation, including Dharragarra, Opalios, Parvopalus, Steropodon, and Stirtodon.
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.
Teinolophos is a prehistoric species of monotreme, or egg-laying mammal, from the Teinolophidae. It is known from four specimens, each consisting of a partial lower jawbone collected from the Wonthaggi Formation at Flat Rocks, Victoria, Australia. It lived during the late Barremian age of the Lower Cretaceous.
The long-beaked echidnas make up one of the two extant genera of echidnas: there are three extant species, all living in New Guinea. They are medium-sized, solitary mammals covered with coarse hair and spines made of keratin. They have short, strong limbs with large claws, and are powerful diggers. They forage in leaf litter on the forest floor, eating earthworms and insects.
The short-beaked echidna, also called the short-nosed echidna, is one of four living species of echidna, and the only member of the genus Tachyglossus. It is covered in fur and spines and has a distinctive snout and a specialised tongue, which it uses to catch its insect prey at a great speed. Like the other extant monotremes, the short-beaked echidna lays eggs; the monotremes are the only living group of mammals to do so.
The western long-beaked echidna is one of the four extant echidnas and one of three species of Zaglossus that occurs in New Guinea. Originally described as Tachyglossus bruijnii, this is the type species of Zaglossus.
The eastern long-beaked echidna, also known as Barton's long-beaked echidna, is one of three species from the genus Zaglossus to occur in New Guinea. It is found mainly in the eastern half at elevations between 2,000 and 3,000 metres.
Megalibgwilia is a genus of echidna known only from Australian fossils that incorporates the oldest-known echidna species. The genus ranged from the Pliocene until the late Pleistocene, becoming extinct about 50,000 years ago. Megalibgwilia species were more widespread in warmer and moist climates. Their extinction can be attributed to increasing aridification in Southern Australia.
Monotremes are mammals of the order Monotremata. They are the only group of living mammals that lay eggs, rather than bearing live young. The extant monotreme species are the platypus and the four species of echidnas. Monotremes are typified by structural differences in their brains, jaws, digestive tract, reproductive tract, and other body parts, compared to the more common mammalian types. Although they are different from almost all mammals in that they lay eggs, like all mammals, the female monotremes nurse their young with milk.
Kryoryctes is a genus of prehistoric monotreme mammal from the Early Cretaceous (Albian) Eumeralla Formation of Victoria, Australia from the Otway Group of Dinosaur Cove. It is known only from a partial right humerus, estimated at 106 million years old, and contains one species, Kryoryctes cadburyi. The holotype, NMV P208094, was described in 2005 and is currently housed in the Museums Victoria Palaeontological Collection.
Yinotheria is a proposed basal subclass clade of crown mammals uniting the Shuotheriidae, an extinct group of mammals from the Jurassic of Eurasia, with Australosphenida, a group of mammals known from the Jurassic to Cretaceous of Gondwana, which possibly include living monotremes. Today, there are only five surviving species of monotremes which live in Australia and New Guinea, consisting of the platypus and four species of echidna. Fossils of yinotheres have been found in Britain, China, Russia, Madagascar and Argentina. Contrary to other known crown mammals, they retained postdentary bones as shown by the presence of a postdentary trough. The extant members (monotremes) developed the mammalian middle ear independently.
Vombatus hacketti, Hackett's wombat, is an extinct species of wombat that lived in Southwest Australia during the Late Pleistocene. It survived until very recently, going extinct between 10,000 and 20,000 BP.
Teinolophidae is an extinct family of small mammals that are among the earliest known monotremes and were endemic to what would become Australia. Two genera have been described as belonging to this family: Teinolophos, and Stirtodon.
Opalios is an extinct genus of monotreme mammal from the Late Cretaceous (Cenomanian) Griman Creek Formation of Australia. The genus contains a single species, O. splendens, known from a fragmentary left dentary.
Dharragarra is an extinct genus of monotreme mammal from the Late Cretaceous (Cenomanian) Griman Creek Formation of Australia. The genus contains a single species, D. aurora, known from a partial left mandibular ramus. Dharragarra was likely more closely related to the living platypus than many other monotremes of the Cretaceous.
Parvopalus is an extinct genus of monotreme mammal from the Late Cretaceous (Cenomanian) Griman Creek Formation of Australia. The genus contains a single species, P. clytiei, known from a partial left dentary.
Ornithorhynchoidea is a superfamily of mammals containing the only living monotremes, the platypus and the echidnas, as well as their closest fossil relatives, to the exclusion of more primitive fossil monotremes of uncertain affinity.
