| 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 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.[1] 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.[2][3][4]
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.
- ^ Rubidge, B. S. (ed.) 1995b. Biostratigraphy of the Beaufort Group (Karoo Supergroup). South African Committee of Stratigraphy. Biostratigraphic Series 1. Pretoria, Council for Geoscience.
- ^ Hancox, P.J; Rubidge, B.S (2001-01-01). "Breakthroughs in the biodiversity, biogeography, biostratigraphy, and basin analysis of the Beaufort group". Journal of African Earth Sciences. 33 (3–4): 563–577. Bibcode:2001JAfES..33..563H. doi:10.1016/S0899-5362(01)00081-1. ISSN 1464-343X.
- ^ Rubidge, Bruce S.; Day, Michael O.; Barbolini, Natasha; Hancox, P. John; Choiniere, Jonah N.; Bamford, Marion K.; Viglietti, Pia A.; McPhee, Blair W.; Jirah, Sifelani (2016), "Advances in Nonmarine Karoo Biostratigraphy: Significance for Understanding Basin Development", Origin and Evolution of the Cape Mountains and Karoo Basin, Regional Geology Reviews, Springer International Publishing, pp. 141–149, doi:10.1007/978-3-319-40859-0_14, ISBN 9783319408583
- ^ van der Walt, Merrill; Day, Michael; Rubidge, Bruce; Cooper, Antony; Netterberg, Inge (2010-12-31). "A new GIS-based biozone map of the Beaufort Group (Karoo Supergroup), South Africa". Palaeontologia Africana. 45: 1–6.