What is "diadectes"

Diadectes (meaning crosswise-biter) is an extinct genus of large, very reptile-like amphibians that lived during the early Permian period ( Cisuralian epochs, between 290 and 272 million years ago). Diadectes was one of the very first herbivorous tetrapods, and also one of the first fully terrestrial animals to attain large size.