Trechnotheria
| Trechnotherians Temporal range: Late Triassic - Holocene, 216.5–0 Ma |
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| Kangaroo with her joey | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Clade: | Holotheria |
| Clade: |
Trechnotheria McKenna, 1975 |
| Subgroups | |
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| Synonyms | |
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Theriiformes Rowe, 1988 |
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Theriiformes Rowe, 1988
Trechnotheria is a group of mammals that includes the therians and some fossil mammals from the Mesozoic Era. In the Jurassic through Cretaceous periods, the group was endemic to what would be Asia and Africa.
Trechnotheria has been assigned various ranks, but was originally called a "superlegion" by the original author. One reference has defined the Trechnotheria as the clade comprising the last common ancestor of Zhangheotherium and living therian mammals, and all its descendants.
Like most Mesozoic mammal groups, early trechnotherians are known mainly from their teeth. Hence, one of the most prominent features of this group is the "hypertrophied postvallum/prevallid shearing mechanism", along with other dental characters. Features of the shoulder blade, tibia, humerus, and ankle joint also diagnose this clade.
A cladogram compiled by Mikko Haaramo and based on individual cladograms of after After Luo, Cifelli & Kielan-Jaworowska, 2001, Luo, Kielan-Jaworowska & Cifelli, 2002 and, Kielan-Jaworowska, Cifelli & Luo, 2004.
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