Vertebrate Life

Important Dates from vertebrate zoology that I don't want to erase but will probably never look at again:
Chengiang Fuana - soft bodied fossils - 520 MYA
Ostracoderms - Ordivician - 480 MYA
Gnathostomes - early Silurian
Placodonts - early Silurian to late Devonian - 440-360 MYA
Acanthodians - late Ordovician to early Permian - 443-300 MYA
Chondrichthyes - early Devonian
Oldest true frogs - early Jurassic - 190 MYA
Oldest salamanders and caecilians - Jurassic
Oldest turtles - Triassic - Proganochelys from Germany 210 MYA, Odontochlyes from Thailand, Argentina and China - 220 MYA