The Early Triassic in Mesozoic spanned from
299 to
270 millon years ago. The explanation in brackets is the ages they lived in extinct species. Note that
Mya is million years ago. For example, "48.6~40.4 Mya" shows a range between 48.6 and 40.4 million years ago. The italic and bold figures, e.g.
488, show out of the range. The time range is shown in the
Geological Time Table. The followings are a part of the Evolutionary Tree.
Triassic, Early Triassic,
Middle Triassic,
Late TriassicThe right map is the continents at Early Triassic provided by
C. R. Scotese PALEOMAP Project.
| 251 Mya |
| 251~249.7 Mya |  | Mammal-like reptile | Ericiolacerta , Galesaurus |
 | Marine reptile | Hovasaurus |
 | Archosaurs | Proterosuchus |
| First frog fossil |
 | Frog | Triadobatrachus |
 | Coelacanth | Laugia |
| 251~245 Mya |  | Primitive turtle | Procolophon |
 | Lizard | Paliguana (Earliest Lepidosauromorpha) |
 | Archosaurs | Kalisuchus , Tasmaniosaurus , Chasmatosuchus |
 | Primitive amphibia | Uranocentrodon , Broomistega |
| 251~216.5 Mya |  | Vascular plant | Pleuromeia |
| 251~199.6 Mya |  | Marine reptile | Grippia |
 | Sea star | Aspiduriella |
| 251~183 Mya |  | Sea urchin | Eodiadema |
| 251~145.5 Mya |  | Cycad | Williamsoniella (Great Dying④) |
 | Ginkgo | Pachypteris (Great Dying④) |
| 251~136.4 Mya |  | Fern | Eboracia (Great Dying④) |
| 251~99.6 Mya |  | Cycad | Otozamites (Great Dying④) |
| 251~61.7 Mya |  | Sea lily | Pentacrinus (Great Dying④⑤) |
| 249.7 Mya |
| 249.7~245 Mya |  | Marine reptile | Chaohusaurus , Utatsusaurus , Hupehsuchus |
 | Primitive amphibia | Aphaneramma |
 | Coelacanth | Whiteia |
 | Shrimp | Litogaster , Ambilobeia |
| 249.7~228 Mya |  | Mammal-like reptile | Cynognathus |
 | Marine reptile | Cymbospondylus , Placodus |
| 249.7~203.6 Mya |  | Archosaurs | Paleorhinus |
| 249.7~199.6 Mya |  | Shell | Monotis |
| 247.2~99.6 Mya |  | Cycad | Williamsonia (Great Dying④) |
| 249.7~70.6 Mya |  | Lungfish | Ceratodus (Great Dying④) |