II. Timescale and Horse Family Tree
|
|
| Recent |
10,000 years ago to present |
| Pleistocene |
2.5-0.01 My (million years ago) |
| Pliocene |
5.3-2.5 My |
| Miocene |
24-5.3 My |
| Oligocene |
34-24 My |
| Eocene |
54-34 My |
|
|
And here's the tree...note that the timescale is a bit weird (e.g. the
Oligocene is compressed almost to nothing) to keep it from being too long. All
the names on the tree are genus names, so recall that each genus encompasses a
cluster of closely related species.
2My Old & New World Equus
\ | /
\ | /
4My Hippidion Equus Stylohipparion
| | Neohipparion Hipparion Cormohipparion
| | Astrohippus | | |
| | Pliohippus ---------------------------
12My Dinohippus Calippus \ | /
| | Pseudhipparion \ | /
| | | |
------------------------------------------- Sinohippus
15My \ | / |
\ | / Megahippus |
17My Merychippus | |
| Anchitherium Hypohippus
| | |
23My Parahippus Anchitherium Archeohippus
| | |
(Kalobatippus?)-----------------------------------------
25My \ | /
\ | /
|
35My |
Miohippus Mesohippus
| |
40My Mesohippus
|
|
|
45My Paleotherium |
| Epihippus
| |
Propalaeotherium | Haplohippus
| | |
50My Pachynolophus | Orohippus
| | |
| | |
------------------------------
\ | /
\ | /
55My Hyracotherium
| 
