Monotremes
Monotremes
The order Monotremata (one-holed creatures) is comprised of two families, the Ornithorhynchidae, including the platypus, and the Tachyglossidae, including the long- and short-beaked spiny anteaters or echidnas. Monotremes are found only in Australia, Tasmania, and New Guinea. Monotremes are a derivative of an ancient mammal stock but there is no direct evidence of what it might have been.
Monotremes are not closely related to marsupials or placental mammals, but rather they evolved from a distinct group of reptilian ancestors. Despite sharing some reptilian features, monotremes possess all the major mammalian characteristics: air breathing, en-dothermy (i.e., they are warm-blooded), mammary glands, a furred body, a single bone in the lower jaw, and three bones in the middle ear.
Monotremes have a reptilian-like shoulder girdle with distinct coracoid bones and a T-shaped interclavi-cle. Other reptilian-like skeletal features are present, including certain ribs and vertebral processes, as well as epipubic or "marsupium" bones. These bones are rudimentary and analogous to those that support a pouch in present-day marsupials. However, it seems more likely that these bones are a vestige from reptilian ancestors, associated with the attachment of strong abdominal muscles to support large hindquarters.
Unlike higher mammals with separate reproductive and excretory systems, monotremes have a cloaca, with only one external opening for excretion and reproduction, as in birds and reptiles. In male monotremes, the penis is used only for the passage of sperm and not for urination as in other mammals. The overall pattern of reproduction is mammalian with a brief, vestigial period of development of the young in an external, soft-shelled egg. Once fertilized in the oviduct, the egg is covered with albumen and a tough, leathery shell forms. The egg is rounded, large-yolked, and compressible, rather than brittle like the eggs of birds. Echidnas develop a temporary pouch to incubate the egg and care for the young. The platypus does not develop a pouch and typically lays a single egg in a leaf nest. The mammae lack nipples, so the young lick milk from two lobules in the echidna's pouch or from the abdominal fur of the platypus. A three to six month period of maternal care is typical for monotremes.
monotreme records
This post will discuss monotremes in evolution, but first a diversion… ) left are the monotremes , two species of echidna…
Monotremes are mammals that lay…addition to laying eggs, monotremes have just one opening for reproduction…
Yep. Monotremes and Monotrolls. Monotremes, because they lay eggs . …
Platypus, Ornithorhyncus anatinus
Short-beaked Echidna, Tachyglossus aculeatus
Western Long-beaked Echidna, Zaglossus brujinii
Sir David’s Long-beaked Echidna,
they lay eggs
think platypusMonotremes are egg-laying mammals..so they have hair or fur, not feathers. No, they do not live in trees either. The duck-billed
Yes, just the two of themwth are momotremes
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Marsupials have pouches
If I were to describe the courtship part of it among short-beaked echidnas, I could keep at it for about as long as they do. It’s fascinating, strange and not
While on a little drive with the family we came across an echidna so we stopped for a look. It was a bit harder to pick than we thought with its digging in and sharp spikes but I managed to pick it up
Echidnas are one of the most unique Australian animals. They are very unusual mammals because, like the platypus, they are one of the world’s last surviving monotremes .
Echidnas are one of two “Monotremes”, which are animals that lay eggs but feed their young with milk. The other monotreme is the platypus. What makes these animals “more unique” is that, they are also
Including oviparous, marsupials, viviparous and monotremes. I am a ND student studying animal management, I thought to help people and educate them I’ll put my notes up, but don’t copy if you use them
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Australia, Papua New Guinea, and eastern Indonesia together share all the monotremes (egg-laying mammals) of the world and all the marsupials (pouched
Photo Puzzle, Long-beaked Echidna – foraging. JPF-13158 Long-beaked Echidna – foraging Papua New Gunea, endemic, New guinea highland forests Zaglossus
…t converted into glandular integuments in case of mammals .The synapsids developed mammalian traits , the apocrine gland evolved into milk secreting gland .this apocrine gland is related to hair follicles .there after we see a brief evolutionary stop gap, after which evolved the true egg-laying mammals. These …
