The Monotremes in AE are much more diverse than in HE, but are found in two lines, the Platypus line (Ornithorhynchoidea) and the golden sea duck line (Venatotremata). Echidnas are not present, although one species dwelling in the Tasman might be an echidna, although this is dubious.
Ornithorhynchoidea (Platypus, Bunyip, Beaverpus etc.) Edit
The Ornithorhynchoides are perhaps the most diverse, and weird, of the Monotremes on AE. They range from the 5 species of Platypus (Ornithorhynchus sp.) to the medium sized browsing Chalicotreme (Chalicorostrum papua) of the Pacific islands. One order of Monotremes (the Venatotremata) even managed to colonise the water, proving the group to be much more successful in AE than HE.
Ornithorhynchidae (Platypus, Beaverpus, Bunyip) Edit
This family of Australian endemic Monotremes are perhaps the most familiar. However, the most extreme is the Bunyip (Bunyip Rapaxotaur). The family is found only in Australia, however, the other two families, the Rattornithorhynchidae and the Chalicorostridae, are not only found in Australia, but they are also found in the pacific and even Asia.
The Platypus (Ornithorhynchus anantius) and the Beaverpus (Ornithorhynchus casteroides), are the most familiar of the Monotremes, yet even these two out of five species (The others are the extinct Ornithorhynchus meganatus, and Ornithorhynchus Robustus), who lived in the Miocene–Pliocene. The Platypus is the same as in HE, while the Beaverpus is known to build dams, much like the Beaver of HE, hence its name.
The bunyip (Bunyip rapaxotaur) is the most carnivorous of the platypus line of the monotremes, actively hunting australiornithopods and their young, cooperating in a trio, somewhat like Wolves in HE, albeit with a serrated beak, like the Ichthyornithes. The Bunyip lives in the Australian continent and the Pacific islands, like its competitors, the heterovenators. It has a length of 3 metres and a weight of 50 kg, making it one of the larger mammals of the Dinosaurian Tertiary, at least in Carnivory. (Pic Below).
The Platycroc (Ornithorhynchosuchus australensis), on the other hand, fills the niche of Crocodiles, only in the Mainland, where there are none. In the Palaeocene, it was left vacant, because the last of the Stereospondyls (Descendants of Koolasuchus, however), disappeared in the Middle Palaeocene, the niche of Mainland crocodiles was quickly filled by different creatures. The most successful was that of the Ornithorhynchosuchinae, which looks similar to a already existing Salt Water Crocodile, of the genus Crocodylus, which only lives on the shore lines of various Pacific islands. The Platycroc is around 7 metres long, and can tolerate colder temperatures than its reptilian counterpart.
Chalicorostridae (Chalicotreme and Koalatreme) Edit
This extremely odd family of seemingly recent Monotremes appeared in the Oligocene, and reached their maximum in the Early Pleistocene with the Gigarostrum columbiformes, which reached massive sizes of 3 metres tall and 4 metres long, it was a pure oddity. It, however, represented its family in all their oddities. It had a beak, much like birds, and a body similar to that of a Gorilla. One branch of Chalicorostrids began to colonise the trees, thus producing the Arborotrematinae, which only lives as the Koalatreme.
Chalicorostrinae (Chalicotreme) Edit
The odd looking chalicotreme (Chalicorostrum papua) lives in the Pacific Eco region, and often is the largest herbivore of the islands, with a birds and reptiles usually being the only other tetrapod fauna. Surprisingly, it is one of many large mammalian herbivores of the Dinosaurian Tertiary. At 2 metres long, it browses the trees by lurching forward with its beak, and smashing the plants to a pulp before swallowing. One explorers comment says that it “Looks like a duck, mixed with a horse, and gobbles like turkeys around seeds. One crazy son of a gun”.
Arborotrematinae (Koalatreme) Edit
Its only living relative, the Koalatreme (Arborotrema australensis) is found across the south eastern reaches of the Australian continent. Double the size to a koala of HE, which has failed to exist, due to competition with Arboroorniths and Koalatremes. Like its marsupial counterpart, it is a slow moving animal, but often lives in the thicker branches of Eucalyptus bushes. (Pic Bottom Right).
Rattornithorhynchidae (Alleypus and the Tree Shrew) Edit
This odd family of Ornithorhynchoides first started out in the Miocene, in Australia, without the presence of Rats, which were Rodents, and those simply don’t exist. These Ornithorhynchoides are successful in every way possible, with the most notable forms being the Alleypus and the Tree Shrew.
The alleypus (Rattornithorhynchus graciloides) is one of the smallest Ornithorhynchoides in existence, second to the Tree Shrew. It is around 7cm long, at runs across the ground in swarms, much like its rodent counterpart of HE. It has a shaggy coat, with a thin beak, useful for pecking at insects, much like the Neoscanisoropterygians. However, the Alleypus can avoid competition by being small, and thin, enough to crawl inside the nests, where as there dinosaurian counterparts can’t, as the are simply to big.(Pic Left)
Its smaller relative, the tree shrew (Arborovenator ornithoratto), is the smallest monotreme ever. It is five centimetres long and is a cryptic animal. It is usually heard but not seen, with loud shrieking sounds that determine its existence. It is believed to eat just bees and wasps, plunging their necks and heads in, jabbing at the insects. (Pic above right).
Venatotremata (Golden Sea Ducks, Waitorekes, etc.) Edit
A fully aquatic family of Monotremes that diverged from the Platypus line from the Palaeocene, and proved to be successful. (Coming soon).