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.
Obdurodon is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species Obdurodon insignis, plus Obdurodon dicksoni and Obdurodon tharalkooschild. The species appeared much like their modern day relative the platypus, except adults retained their molar teeth, and unlike the platypus, which forages on the lakebed, they may have foraged in the water column or surface.
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. Within the Ornithorhynchidae are the genera Monotrematum, Obdurodon, and Ornithorhynchus:
Prototheria is an obsolete subclass of mammals which includes the living Monotremata and to which a variety of extinct groups, including Morganucodonta, Docodonta, Triconodonta and Multituberculata, have also been assigned. It is today no longer considered a valid grouping, but rather a paraphyletic evolutionary grade of basal mammals and mammaliaform cynodonts.
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, as was Steropodon. Kollikodon lived in the Late Cretaceous period, during the Cenomanian age.
Steropodon is a genus of prehistoric platypus-like monotreme, or egg-laying mammal. It contains a single species, Steropodon galmani, that lived about 105 to 93.3 million years ago (mya) 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.
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.
Tribosphenida is a group (infralegion) of mammals that includes the ancestor of Hypomylos, Aegialodontia and Theria. It belongs to the group Zatheria. Current definition of Tribosphenida is more or less synonymous with Boreosphenida.
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.
Zaglossus attenboroughi, also known as Attenborough's long-beaked echidna, is one of three species from the genus Zaglossus that inhabits the island of New Guinea. It lives in the Cyclops Mountains, which are near the cities of Sentani and Jayapura in the Indonesian province of Papua. It is named in honour of naturalist Sir David Attenborough.
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.
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 many studies, but this is also disputed.
Murrayglossus is an extinct echidna from the Pleistocene of Western Australia. It contains a single species, Murrayglossus hacketti, also called Hackett's giant echidna. Though only from a few bones, researchers suggest that Murrayglossus was the largest monotreme to have ever lived, measuring around 1 metre (3.3 ft) long and weighing around 20–30 kilograms (44–66 lb). Historically treated as a species of long-beaked echidnas, it was separated into its own genus Murrayglossus in 2022. The generic name combines the last name of paleontologist Peter Murray and glossus, the Greek word for "tongue".
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.
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.
The monotremes represent the order of extant mammals most distantly related to humans. The platypus is indigenous to eastern Australia; the short-beaked echidna is indigenous to Australia and Papua New Guinea; whereas the long-beaked echidna is restricted to Papua New Guinea and Irian Jaya. Since monotremes exhibit characteristics common with both reptiles and therian mammals, they are of great interest for the study of mammalian evolution.
Teinolophidae is an extinct family of small, carnivorous mammals that were the earliest known monotremes and were endemic to what would become Australia. Two genera are known: Teinolophos, and possibly also Stirtodon.
