Yinotheria
| Yinotheria Temporal range: Late Triassic – Holocene, 210–0 Ma |
|
|---|---|
 |
|
| Ornithorhynchus anatinus (Platypus) | |
 |
|
| Ambondro mahabo jawbone | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Subclass: |
Yinotheria Chow and Rich, 1982 |
| Subgroups | |
Yinotheria is a proposed basal mammalian subclass clade that contains a few fossil of the Mesozoic and the extant monotremes. Today, there are only five surviving species, which live in Australia and New Guinea, but fossils have been found in England, China, Madagascar and Argentina. The surviving species consist of the platypus and four species of echidna.
According to genetic studies Yinotheria first diverge from other mammals around 220 to 210 million years ago, at some point in the Triassic or Early Jurassic. The oldest known fossils are a bit younger, dating around 168 to 163 million years in the Middle Jurassic. These fossils are the genera Pseudotribos of China,Shuotherium of both China and England, Itatodon of Siberia and Paritatodon of Kyrgyzstan and England. These belong to the family Shuotheriidae, and they are the only known northern hemisphere group of yinotherians.
Around the same time as Shuotheriidae, the infraclass Australosphenida first appeared. The family Henosferidae occupied in the southern hemisphere in Argentina and Madagascar with genera Henosferus, Ambondro, and Asfaltomylos. This suggests that this family could have been more widespread and diverse in Gondwana during that time, although due to their fragile state some species might have been destroyed due to geological events.
...
Wikipedia