What are Some Mesozoic Animals?
Mesozoic mammals are clearly not a natural taxonomic unit, including mammals of different classes before the beginning of the Cenozoic (about 5.5 million years ago).
Mesozoic mammals
discuss
- Chinese scientific name
- Mesozoic mammals
- boundary
- animal world
- door
- Chordoma
- Asia Gate
- Vertebrates
- Tsuna
- Lactation
- Classification
- Dozens of genera for six purposes
- Time
- About 5.5 million years ago
- Discovery area
- Yunnan Lufeng
- Mesozoic mammals are clearly not a natural taxonomic unit, including mammals of different classes before the beginning of the Cenozoic (about 5.5 million years ago).
- Mesozoic mammals
- According to the opinions of most recent scholars, excluding the ancestors of modern taxa (monopods, marsupials and placenta, etc.), Mesozoic mammals have six orders and dozens of genera. That is, Prototherians' Multituberculata, Tricondonta, and Docodonta; In addition, Symmetr-odonta, End of Beast Order (Eupantodonta) and Shu Beast Order. The last three orders are the most primitive true beasts, that is, they have not yet reached the level of marsupial structure, and the true beast model of the mandible and teeth (mainly cheek teeth) has not yet been established. Progressive reptiles have similarities.
The Shu beast is a newly established order, represented by the Shu beast found in the Jurassic in Sichuan, China. Its lower molars have a false heel, located before the triangle, which obviously represents another branch of mammal evolution.
The tumour-nosed order is the only protozoa that entered the Cenozoic (Oligocene), and it is the group with the largest variety of fossils, the most abundant fossils, wide distribution, and abnormal specialization in the Mesozoic mammals. The incisors approach rodents, and the cheek teeth are composed of three rows (upper jaw) or two rows (lower jaw), which are similar to the main cheek teeth of a three-row reptile. Tumorous beasts may be burrowing animals, which are ecologically equivalent to modern burrowing rodents. However, some people have recently thought that some species may be arboreal.
With the exception of a few species with more tumours, which are slightly larger (close to rabbits), all other Mesozoic mammals are close to mice or smaller. The period when they lived was the time when dinosaurs lived. They were "little beasts" living in the gaps where all kinds of dinosaurs and all kinds of reptiles lived.
Lufeng, Yunnan, China is the most complete and abundant area where the earliest tricuspid mammals were found (early Jurassic or earlier). Other types of Mesozoic mammalian fossils have also been found in China, but the materials are relatively sporadic. In recent years (1986), Miao Desui discovered that there are three typical mammalian ear bones in the middle ear of the Eocene tumorous mammals in Inner Mongolia, which is one of the important developments in this field.
There have been some changes in the classification of mammals above the taxonomic order (see table).