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Monotreme
Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). 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. In addition, they lay eggs rather than bearing live young, but, like all mammals, the female monotremes nurse their young with milk. Monotremes have been considered members of Australosphenida, a clade that contains extinct mammals from the Jurassic and Cretaceous of Madagascar, South America, and Australia, though this is disputed. The only surviving examples of monotremes are all indigenous to Australia and New Guinea, although there is evidence that they were once more widespread, as ''Monotrematum'' is known from the Paleocene of South America. The extant monotreme species are the platypus and four species of echidnas. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platypus
The platypus (''Ornithorhynchus anatinus''), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal Endemic (ecology), endemic to Eastern states of Australia, eastern Australia, including Tasmania. The platypus is the sole living representative or monotypic taxon of its Family (biology), family (Ornithorhynchidae) and genus (''Ornithorhynchus''), though a number of Fossil Monotremes, related species appear in the fossil record. Together with the four species of echidna, it is one of the five wikt:extant, extant species of monotremes, mammals that lay Egg (biology), eggs instead of giving birth to live young. Like other monotremes, it senses prey through electroreception, electrolocation. It is one of the few species of venomous mammals, as the male platypus has a spur (zoology), spur on the hind foot that delivers a Platypus venom, venom, capable of causing severe pain to humans. The unusual appearance of this egg-laying, duck-billed, beaver-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echidna
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . 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 true anteaters of the Americas, which (along with sloths and armadillos) are xenarthrans. Echidnas live in Australia and New Guinea. Echidnas evolved between 20 and 50 million years ago, descending from a platypus-like monotreme. This ancestor was aquatic, but echidnas adapted to life on land. Etymology Echidnas are named after Echidna, a creature from Greek mythology who was half-woman, half-snake, as the animal was perceived to have qualities of both mammals and reptiles. An alternative explanation is a confusion with . Physical characteristics Echidnas are medium-sized, solitary mamm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short-beaked Echidna
The short-beaked echidna (''Tachyglossus aculeatus''), 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 specialized 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 short-beaked echidna has extremely strong front limbs and claws, which allow it to burrow quickly with great power. As it needs to be able to survive underground, it has a significant tolerance to high levels of carbon dioxide and low levels of oxygen. It has no weapons or fighting ability but repels predators by curling into a ball and deterring them with its spines. It lacks the ability to sweat and cannot deal with heat well, so it tends to avoid daytime activity in hot weather. It can swim if needed. The snout has m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australosphenida
The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. They are thought to have acquired their tribosphenic molars independently from those of Tribosphenida. 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 some studies, but this is disputed. Taxonomy This grouping includes the following taxa: *†Henosferidae, including the genera '' Ambondro'', ''Asfaltomylos'', and ''Henosferus'' from the Jurassic of Argentina and Madagascar. *†Ausktribosphenidae, including the genera ''Ausktribosphenos'', '' Bishops'' from the Lower Cretaceous of Australia and Mid-Cretaceous of Argentina *†''Vincelestes'', sometimes recovered as an australosphenidan (when not inversely considered a cladotherian).Nicholas Chimento, Frederico Agnolin, Agustin Martinelli, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsupials
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a pouch. Marsupials include opossums, Tasmanian devils, kangaroos, koalas, wombats, wallabies, bandicoots, and the extinct thylacine. Marsupials represent the clade originating from the last common ancestor of extant metatherians, the group containing all mammals more closely related to marsupials than to placentals. They give birth to relatively undeveloped young that often reside in a pouch located on their mothers' abdomen for a certain amount of time. Close to 70% of the 334 extant species occur on the Australian continent (the mainland, Tasmania, New Guinea and nearby islands). The remaining 30% are found in the Americas—primarily in South America, thirteen in Central America, and one species, the Virginia opossum, in North America, nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kryoryctes
''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, ''K. cadburyi''. The holotype, NMV P20894, was described in 2005 and is currently housed in the Museums Victoria Palaeontological Collection. Etymology The genus name derives from Greek "kryo", meaning low temperature, in reference to the seasonal coldness common to the paleo-environment of Dinosaur Cove, and from the Greek "oryktes", meaning one who digs, referring to the robust humerus from which a fossorial lifestyle has been inferred. The species is named in honour of Cadbury chocolates, referring to the dark colour of the holotype, as well as for the "recognition and support provided" by Cadbury chocolates during the field work that resulted in discovery of the specimen. Morphology ''K. cadbury ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teinolophidae
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''. ''Teinolophos'' is deeply divergent within monotreme evolution, so Flannery ''et al.'' (2022) proposed to move it into its own family, Teinolophidae, and ''Stirtodon'' was also tentatively assigned to Teinolophidae in the same paper. The skulls of the two teinolophids differed from modern monotremes. Among the contrasts are that, unlike modern monotremes, the teinolophids lacked beaks, and the teinolophids had their ear bones connected to the jaw via the Meckel's cartilage, while modern monotremes have suspended ear bones much like placentals and marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prototherian
Prototheria (; from Greek πρώτος, ''prōtos'', first, + θήρ, ''thēr'', wild animal) is a subclass to which the orders Monotremata, Morganucodonta, Docodonta, Triconodonta and Multituberculata have been assigned, although the validity of the subclass has been questioned. Most of the animals in this group are extinct. The egg-laying monotremes are known from fossils of the Cretaceous and Cenozoic periods; they are represented today by the platypus and several species of echidna. The names Prototheria, Metatheria, and Eutheria (meaning "first beasts", "changed beasts", and "true beasts", respectively) refer to the three mammalian groupings of which we have living representatives. Each of the three may be defined as a total clade containing a living crown-group (respectively the Monotremata, Marsupialia and Placentalia) plus any fossil species which are more closely related to that crown-group than to any other living animals. The threefold division of living mammals in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotrematum
''Monotrematum sudamericanum'' is an extinct monotreme species from the Paleocene (Peligran) Salamanca Formation in Patagonia, Argentina. It is the only monotreme found outside Oceania. Taxonomy A species described in 1992 and assigned to a new genus ''Monotrematum'' as the type. It is currently the only known species of the genus. The authors compared their fossil material to the genus ''Obdurodon'', ornithorhynchid species first discovered at Australian fossil sites in 1975. Description ''Monotrematum sudamericanum'' is known only from two lower and one upper platypus-like teeth. It is the only known non-Australasian ornithorhynchid. The main difference, apart from continent and age, is its size: the teeth of ''Monotrematum'' are around twice as large as those of other similar species in the related genus ''Obdurodon ''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithorhynchidae
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'': *Family Ornithorhynchidae **Genus † ''Monotrematum'' ***†'' Monotrematum sudamericanum'' **Genus †''Obdurodon'' — an ancient branch of the platypus family ***†''Obdurodon dicksoni'' ***†''Obdurodon insignis'' ***†''Obdurodon tharalkooschild'' **Genus ''Ornithorhynchus'' ***''Ornithorhynchus anatinus'' (the modern platypus) Another two genera, ''Steropodon'' and ''Teinolophos'', were originally thought to belong to the Ornithorhynchidae. However, they were both placed into a new family, the Steropodontidae. This decision was made based on differences in the dentary recovered from the Griman Creek Formation, Lightning Ridge, New South Wales, Australia. This dentary is the holot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metatheria
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. There are three extant subclasses of mammals, one being metatherians: #monotremes: egg laying mammals like the platypus and the echidna, #metatheria: marsupials, which includes three American orders ( Didelphimorphia, Paucituberculata and Microbiotheria) and four Australasian orders (Notoryctemorphia, Dasyuromorphia, Peramelemorphia and Diprotodontia), and the # eutherians: placental mammals, consisting of four superorders divided into 21 orders. Metatherians belong to a subgroup of the northern tribosphenic mammal clade or Boreosphenida. They differ from all other mammals in certain morphologies like their dental formula, which includes about five upper and four lower incisors, a canine, three pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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