Middle Ordovician

Great Ordovician Biodiversity Event

The Middle Ordovician (470-459 Ma) is a time period that occurs after the Floian (Early Ordovician), and before the Sandbian (Late Ordovician)

Flora (plants, fungi, bacteria)

The earliest unambiguous fossil evidence of land plants can be traced to Dapingian, which is represented by dyads and tetrahedral tetrads (microfossils) from the Gondwana paleo-continent
Earliest known macrofossils of bryophytes from the late Middle Ordovician of Tennessee (Retallack 2019)
- Liverworts, mosses, and hornworts are all present at the site
Plant life existed on the margins of the land in the Dapingian
- By the Darriwilian, plants lived along river valleys and flood plains, far from open water
Fossilized fungi hyphae have been recovered from the middle Ordovician of Wisconsin
- These were mycorrhizal fungi: symbiotic fungi serve as, or are associated with, plants (Redecker et al. 2000)
- Retallack (2019) also found endomycorrhiza and lichens
- This suggests plants were growing in regions where they were not covered with water, and therefore required a method of extracting minerals from primitive soils, at least for substantial periods of time

Fauna

Great Ordovician Biodiversity Event (GOBE)
- Explosion of invertebrate life
- Evidence of very early vertebrates