Type
Zone
Age range
453.7–452.8 Ma
Late Ordovician
Katian
Sandbian
Plectodina tenuis
Phragmodus undatus
Belodina compressa
453.7453.6453.6453.6453.5453.4453.4453.4453.3453.3453.2453.1453.1453.1453.0452.9452.9452.9452.8