Diadectidae

Diadectidae are a family of large reptile-like tetrapods that lived in Euramerica during the Carboniferous and early Permian periods. They are the very first herbivorous tetrapods to appear, and also the first fully terrestrial animals to attain large size. They represent an important stage in both vertebrate evolution and terrestrial ecosystems; the exploitation of plant material in the food chain.

The best known and also the largest representative of the family is Diadectes a heavily built animal that attained a maximum length of 3 meters. However several other genera, and various fragmentary fossil remains, are also known. Although well known genera like Diadectes only first appear in the Late Pennsylvanian, fragmentary remains of what may or may not be similar animals are known from much earlier, including a piece of lower jaw of a possibly herrbivorous tetrapod found in Mississippian (Chesterian) strata from Tennessee (probably the Bangor Formation).