Tetragonias fossil map
Where fossils of Tetragonias have been found, shown on the Earth as it looked about 252 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 252 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Pre-mammals (synapsids) |
|---|---|
| Lived | 247–241.464 million years ago |
| Periods | Triassic |
| Family | Shansiodontidae |
| Named by | Cruickshank 1967 |
| Fossil records | 2 occurrences at 2 locations (PBDB) |
| Found in | Tanzania |
| Rock formations | Manda Beds |
About Tetragonias
Tetragonias is an extinct genus of dicynodont from the Anisian Manda Beds of Tanzania. With tetra meaning "four," and goni meaning "angle," the name references the square shape of the Tetragonias skull when viewed dorsally. Not to be confused with the plant Tetragonia, Tetragonias were dicynodont anomodonts discovered in the late 1960s by paleontologist A. R. I. Cruickshank in the Manda Formation. Only the type species, T. njalilus, has been recognized.
Originally thought to have existed during the lower Middle Triassic age, also called the Anisian age, Gay and Cruickshank (1999) later postulated that the Manda Formation may have actually been of the Ladinian age. This terrestrial herbivore was determined to have relation to the genera Lystrosaurus and Kannemeyeria.
Text in “About” is quoted from the Wikipedia article Tetragonias (revision 1321712699), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q2309862.
