What is "trechnotheria"

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.