The Pridoli Epoch (423-419 Ma) is the Late Silurian, occurring after the Ludlow Epoch, and before Lochkovian (Early Devonian)
Climate becomes warmer
Plate tectonic activity shifts continents
Gondwana drifted farther across the South Pole
Siberia, Laurentia, and Baltica clustered around the equator.
Laurentia and Baltica collided at the end of the Silurian, forming a new supercontinent, Euramerica,
New mountain ranges extending from present-day Scandinavia through Britain and into North America formed through the Caledonian orogeny
Formation of extensive evaporite (salt) deposits near the equator.
Large glacier melt & sea levels rise
Nearly continuous sea from New York to Nevada, and other shallow seas still covered parts of other continents
~420 Ma, earliest unequivocal evidence of stomata in Cooksonia pertoni (Edwards et al. 1998)
Flora
Oldest land plant macrofossils found
Bryophytes diversify on landscape
Branched sporophytes on the landscape, possibly originating in the Early Silurian
Eophytes: no direct evidence but probably on the landscape
Horneophytes: Caia, Tortilicaulis
Vascular plants also on the landscape in the Late Silurian
Rhyniophytes: Eocooksonia (=Cooksonella), Eorhynia, Filiformorama, Pertonella, Salopella, Steganotheca
Cooksonioids: Aberlemnia, Cooksonia,
Zosterophylls: Jugumella, Zosterophyllum
Lycopsids: Lycopodolica
Euphyllophytes?: Hostinella, Psilophytites, Wutubulaka
Fungi
Diversification of land fungi
Fauna
Coral reefs first appear
Early arachnids, including relatives of spiders (trigonotarbids) & scorpions
Millipedes continue, and centipedes first appear
Evolution of fishes; diversification of jaw-less fish