File:Monotreme reproductive negeriku.info - Wikimedia Commons
The earliest known fossilised monotreme was found in Australia and dated to Ma. Remember, that's monotremes in general, not the platypus itself, which. Monotremes are mammals that are best known for laying eggs, instead of giving In Australia, the earliest known marsupial fossils date to around million. Monotremes are one of the three main groups of living mammals, along with placentals . All these dates are more recent than the oldest known platypus fossils; and, if correct, suggest that both the short-beaked and long-beaked echidna.
Monotreme Monotremes are mammals that are best known for laying eggs, instead of giving birth to live young like marsupials and placental mammals eutheria. The word monotreme comes from the Greek words mono- and trema, meaning "one" and "hole. Like other mammals, monotremes are " warm-blooded " with high metabolic rates though not as high as other mammalssee below.
Ina fossil tooth of a million-year-old platypus was found in southern Argentinasince named Monotrematum.
In Australia, the earliest known marsupial fossils date to around million years ago. Platypus has only one genus comprising one species: There are three species of echidna in two genera: Tachyglossus aculeatus, Zaglossus bruijnii and Zaglossus attenboroughi.
Living monotremes lack teeth as adults.
Yinotheria - Wikipedia
Fossil forms and modern platypus young have the "tribosphenic" three-cusped molars which are one of the hallmarks of mammals. However, recent work suggests that monotremes acquired this form of molar independently of placental mammals and marsupials. As in all true mammals, the tiny bones that conduct sound to the inner ear are fully incorporated into the skull, rather than lying in the jaw as in cynodonts and other pre-mammalian synapsids.
However, the external opening of the ear still lies at the base of the jaw. The monotremes also have extra bones in the shoulder girdle, including an interclavicle, which are not found in other mammals. This figure is similar to that of other animals that eat ants and termites;  burrowing animals also tend to have low metabolism generally. Another hypothesis is that they are descended from ectothermic ancestors, but have taken to periodic endothermy for reproductive reasons, so that the young can develop more quickly.
Termites from the Rhinotermitidae family are avoided due to their chemical defences. Scarab beetle larvae are also a large part of the diet when and where available.
They may rapidly dig themselves into the ground if they cannot find cover when in danger. Instead, they use the colour of their spines, which is similar to the vegetation of the dry Australian environment, to avoid detection.
They have good hearing and tend to become stationary if sound is detected. In agricultural areas, they are most likely to be found in uncleared scrub; they may be found in grassland, arid areas, and in the outer suburbs of the capital cities. Little is known about their distribution in New Guinea. They have been found in southern New Guinea between Merauke in the west and the Kelp Welsh River, east of Port Moresbyin the east, where they may be found in open woodland. They have also been seen crossing streams and swimming for brief periods in seas off Kangaroo Island.
Short-beaked echidna - Wikipedia
They swim with only the snout above water, using it as a snorkel. Trains of up to 10 males, often with the youngest and smallest male at the end of the queue,  may follow a single female in a courtship ritual that may last for up to four weeks; the duration of the courtship period varies with location.
This process can take a few hours, and the female can reject the suitor by rolling herself into a ball. They can lie with heads facing one another, or head to rear. Sperm bundles of around each appear to confer increased sperm motility, which may provide the potential for sperm competition between males.
Gestation takes between 21 and 28 days after copulation,  during which time the female constructs a nursery burrow. The egg is ovoid, leathery, soft, and cream-coloured.
Between laying and hatching, some females continue to forage for food, while others dig burrows and rest there until hatching. Although newborns are still semitranslucent and still surrounded by the remains of the egg yolk, and the eyes are still barely developed, they already have well-defined front limbs and digits that allow them to climb on their mothers' bodies. There is no contact between the mother and young after this point.
At the moment of birth, the solution is dilute and contains 1. Mature milk has much more concentrated nutrients, with Lactose production is believed to proceed along the same lines as in the platypus. A year field study found the short-beaked echidna reaches sexual maturity between five and 12 years of age, and the frequency of reproduction varies from once every two years to once every six years.
Weak identity between chromosomes results in meiotic pairing that yields only two possible genotypes of sperm, X1X2X3X4X5 or Y1Y2Y3Y4, thus preserving this complex system.
However, areas where the land has been completely cleared for single crops that can be mechanically harvested, such as wheat fields, have seen extinctions. Goannas are known for their digging abilities and strong sense of smell, and are believed to have been the main predators of the echidna before the introduction of eutherian mammals. The killing of echidnas was a taboo in traditional culture, but since the tribespeople have become increasingly Westernised, hunting has increased, and the animals have been more easily tracked down due to the use of dogs.
This waterborne infection is contracted through sharing drinking areas with infected dogs, foxes, cats, and dingos, which do not die from the parasite. The infection is seen as being more dangerous in drier areas, where more animals are sharing fewer bodies of water, increasing the chance of transmission.
Echidnas are also known to be affected by other tapeworms, protozoans and herpes-like viral infections, but little is known of how the infections affect the health of the animals or the populations.
Skinny 'Shrew' Is Oldest True Mammal
InPerth Zoo managed to breed some captive short-beaked echidnas,  and in the first zoo-born echidnas were successfully bred there. The other four cases occurred in the Northern Hemisphere, two in the United States and the others in western Europe.
In these cases, breeding occurred six months out of phase compared to Australia, after the animals had adapted to Northern Hemisphere seasons. The species was a totem for some groups, including the Noongar people from Western Australia. Many groups have myths about the animal; one myth explains it was created when a group of hungry young men went hunting at night and stumbled across a wombat.El ex miembro de los Illuminati que rompió el silencio sobre la secta y reveló 8 de sus secretos
They threw spears at the wombat, but lost sight of it in the darkness.