The Early Ordovician in Paleozoic spanned from
488 to
472 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.
Ordovician, Early Ordovician,
Middle Ordovician,
Late OrdovicianThe right map is the continents at Middle Ordovician provided by
C. R. Scotese PALEOMAP Project.
| 488.3 Mya |
| 488.3~449 Mya |  | Trilobite | Neseuretus |
| 488.3~445.6 Mya |  | Sea bud | Echinosphaerites |
 | Cephalopod | Cameroceras (9m) |
 | Trilobite | Remopleurides , Triarthrus |
| 488.3~443.7 Mya |  | Cephalopod | Endoceras |
| 488.3~418.7 Mya | | First coral fossil |
 | Coral | Catenipora (Great Dying①), Palaeophyllum (Great Dying①) |
| 488.3~359.2 Mya |  | Coral | Streptelasma (Great Dying①) |
| 488.3~345 Mya | | First bivalve fossil |
 | Bivalve | Ctenodonta (Great Dying①②) |
| 488.3~260.5 Mya |  | Mollusc | Tentaculites (Great Dying①) |
| 488.3~203.6 Mya |  | Gastropoda | Maclurites (Great Dying①②③) |
| 488.3~0 Mya |  | Lamp shell | (Lingula shells) (Great Dying①②③④⑤) |
| 488 Mya |
| 488~472 Mya |  | Aplacophora | Strophomenia |
 | Cephalopod | Estonioceras |
 | Trilobite | Opipeuterella |
| 488~443 Mya |  | Trilobite | Neoasaphus |
| 488~250 Mya |  | Green algae | Receptaculites (Great Dying①②) |
| 479 Mya |
| 479~466 Mya |  | Jellyfish | Eoconularia |
 | Jawless fish | Pircanchaspis |
| 479~460.5 Mya |  | Jawless fish | Arandaspis |
| 479~457.5 Mya |  | Hemichordata | Isograptus |
 | Sea bud | Mimocystites |
 | Trilobite | Reedocalymene |
 | Jawless fish | Sacabambaspis |
| 479~449 Mya |  | Cystoid | Hemicosmites |
 | Jawless fish | Anatolepis |
| 479~445.6 Mya |  | Hemichordata | Dicranograptus |
 | Echinoderm | Cothurnocystis |
 | Trilobite | Isotelus (72cm) |
| 479~443.7 Mya |  | Trilobite | Synhomalonotus |
| 479~422.9 Mya |  | Echinoderm | Hemicystites (Great Dying①) |
| 479~418.1 Mya |  | Hemichordata | Climacograptus (Great Dying①) |
| 479~203.6 Mya |  | Cephalopod | Michelinoceras , Orthoceras (Great Dying①②③) |
| 479~0 Mya |  | Bivalve | (Nut clams) (Great Dying①②③④⑤) |
| 476.8 Mya |
| 476.8~460.5 Mya |  | Jawless fish | Porophoraspis |
| 476.8~457.5 Mya |  | Trilobite | Colpocoryphe |
| 478.6 Mya |
| 478.6~466 Mya |  | Gastropoda | Euomphalopsis |
 | Cephalopod | Cassinoceras |
| 478.6~443.7 Mya |  | Cephalopod | Tarphyceras |
| 478.6~199.6 Mya |  | Gastropoda | Euomphalus (Great Dying①②③) |