Tropidostoma Assemblage Zone
The Tropidostoma Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 240 metres (790 ft), occur from east of Sutherland through to Beaufort West and Victoria West, to areas south of Graaff-Reinet. Its northernmost exposures occur west/north-west of Colesberg. The Tropidostoma Assemblage Zone is the fourth biozone of the Beaufort Group.
| Tropidostoma Assemblage Zone | |
|---|---|
| Stratigraphic range: Late Permian | |
Tropidostoma microtrema | |
| Type | Biozone |
| Unit of | Lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group |
| Underlies | Cistecephalus Assemblage Zone |
| Overlies | Pristerognathus Assemblage Zone |
| Thickness | up to 787.402 feet (240 m) |
| Location | |
| Region | Northern, Western & Eastern Cape |
| Country | South Africa |
| Extent | Karoo Basin |
| Type section | |
| Named for | Tropidostoma microtrema |
| Named by | Keyster & Smith |
| Year defined | 1978-79 |
The name of the biozone refers to Tropidostoma microtrema, a herbivorous dicynodont therapsid. This biozone is characterized by the presence of this species in association with another dicynodont species, Endothiodon uniseries.