The Paleozoic
Import from Icebergcharts.com (old website).

Tier 1
Trilobites
Permian triassic extinction
Cambrian explosion
Anomalocaris
Dimetrodon
Tier 2
Placoderms
Brachiopods
Crinoids
Giant insects
Tiktaalik
Sea scorpions
Tier 3
Great Ordovician biodiversification event
Capitanian extinction
Ordovician-Silurian extinction
Conodonts
Tully monster
Paleozoic evoluionary fauna
Carbeniferous rainforest collapse
Tier 4
Blastoids
Tabulates
Stenolaemata
Graptolites
Rugose corals
Ostracoderms
Isoxys
Tier 5
Cystoids
Saccorhytida
Hyoliths
Paleo-tethys
Megacheira
Fusulinids
Paleodictyon
Paleozoic ammonoids
Lapetus ocean
Tier 6
Taghanic event
Palaeonisciformes
Eocrinoids
Archaeochyatha
Edrioasteroidea
Romer's gap
Hederellids
Stromatoporoids
Acanthodii
Silurian minor extinctions
Tier 7
Typhloesus
Protocoleoptera
Thylacocephala
Paleozoic stomatopods
Giuyu oneiras
Euthycarcinoidea
Qikiqtania
Ediacaran survivors
Tier 8
Parablastoids
Paterinata
Paracrinoids
Timerellida
Bear gulch
Bradoriida
Bellerophontida
Serpukhovian extinction
Dasberg event
Gogo reef
Ceratid takeover of Ammonoid fauna
Tomotiids