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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 echidna ... [...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 to eastern Australia, including Tasmania. The platypus is the sole living representative or monotypic taxon of its family ( Ornithorhynchidae) and genus (''Ornithorhynchus''), though a number of related species appear in the fossil record. Together with the four species of echidna, it is one of the five extant species of monotremes, mammals that lay eggs instead of giving birth to live young. Like other monotremes, it senses prey through electrolocation. It is one of the few species of venomous mammals, as the male platypus has a spur on the hind foot that delivers a venom, capable of causing severe pain to humans. The unusual appearance of this egg-laying, duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, and the first scientists to examine a preserved platypus body (i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Long-beaked Echidna
The eastern long-beaked echidna (''Zaglossus bartoni''), 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 . Description The eastern long-beaked echidna can be distinguished from other members of the genus by the number of claws on the fore and hind feet: it has five claws on its fore feet and four on its hind feet. Its weight varies from ; its body length ranges from ; it has no tail. It has dense black fur. It rolls into a spiny ball for defense. They have a lifespan of roughly 30 years. Like the closely related platypus, echidnas have spurs on their hind legs. Unlike the platypus, echidna spurs are not venomous. All eastern long-beaked echidnas start with spurs on their hind feet and spur sheaths that cover them. Females typically lose their spurs later in life while males keep them. Females are also generally larger than males. Body mass tends to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class (biology), class Mammalia (), characterized by the presence of mammary glands which in Female#Mammalian female, females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three ossicles, middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they Genetic divergence, diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant taxon, extant species of mammals have been described divided into 29 Order (biology), orders. The largest Order (biology), orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, Mole (animal), 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, pinniped, seals, and others). In terms of cladistic ... [...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 i ... [...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, solitar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutheria
Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are distinguished from noneutherians by various phenotypic traits of the feet, ankles, jaws and teeth. All extant eutherians lack epipubic bones, which are present in all other living mammals (marsupials and monotremes). This allows for expansion of the abdomen during pregnancy. The oldest-known eutherian species is ''Juramaia sinensis'', dated at from the early Late Jurassic ( Oxfordian) of China. Eutheria was named in 1872 by Theodore Gill; in 1880 Thomas Henry Huxley defined it to encompass a more broadly defined group than Placentalia. Characteristics Distinguishing features are: *an enlarged malleolus ("little hammer") at the bottom of the tibia, the larger of the two shin bones *the joint between the first metatarsal bone and the entocuneiform bone (the innermost of the three cunei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Long-beaked Echidna
The western long-beaked echidna (''Zaglossus bruijnii'') 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''. Description The western long-beaked echidna is an egg-laying mammal. Unlike the short-beaked echidna, which eats ants and termites, the long-beaked species eats earthworms. The long-beaked echidna is also larger than the short-beaked species, reaching up to ; the snout is longer and turns downward; and the spines are almost indistinguishable from the long fur. It is distinguished from the other ''Zaglossus'' species by the number of claws on the fore and hind feet: three (rarely four). It is the largest extant monotreme. Distribution and habitat The species is found in the Bird's Head Peninsula and Foja Mountains of West Papua and Papua provinces, Indonesia, respectively, in regions of elevation between ; it is absent from ... [...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 ... [...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. c ... [...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 Mart ... [...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 th ... [...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''. The teeth of ''M. sudamericanum'' presently reside in the collections of Museo de La Plata and Museo Paleontológico Egidio Feruglio The Museum of Pale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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