Mississippian Epoch
Age of weedy pteridosperms and early tetrapods
The Mississippian (358.9–323 Ma) is a time period that demarcates the early Carboniferous, occurring after the Late Devonian, and before the Pennsylvanian (or Late Carboniferous)
Geologic Age
358.9–323.2 Ma
Subdivisions
Serpukhovian: 330.9±0.3–323.2±0.4 Ma
Visean: 346.7±0.4–330.9±0.3 Ma
Tournaisian: 358.9±0.4–346.7±0.4 Ma
Eon / Era / Period / Epoch
What happened during this time?
Geophysical
The climate in the Early Mississippian is hot and warm but becomes cooler and wetter toward the end
The Epoch begins with carbon dioxide levels around 3,500 ppm, and ends with ~700 ppm
Oxygen levels are some of the highest at around 31.9%
Biological
Flora
The earliest forests of the Devonian were devastated by the Late Devonian extinction
Shrubby pteridosperms now dominate the landscape where progymnosperms, like aneurophyte vines and archaeopterid trees stood
Seed ferns, like the Lyginopteridales and Medullosales diversify during the Mississippian
The progymnosperms, such as the Stenokoleales and the Noeggerathians are on the landscape; Stenokolales go extinct at the end of the Mississippian
Protolepidodenrids survive until the end of the Mississippian
The Late Mississippian begins the dominance of the arborescent lycopsids (e.g., Lepidodendron) and arborescent horsetails, (e.g. Calamites)
The Sphenophyllales dominate as understory, shrubby plants, as well as the Zygopteridales and Stauropteridales ferns
Some cladoxylopsid ferns still survive (e.g. Cladoxylon) until the Late Mississippian
Some modern leptosporangiate ferns (Polypodiidae) begin to appear
Fauna
Terrestrial invertebrates increase in new niches created by plants
Tetrapods radiate extensively, especially the Whatcheeriidae and Crassigyrinidae
The first 15 million years of the Carboniferous had very limited terrestrial fossils, known as Romer's gap
There is decrease of the Devonian fish-like ichthyostegalian labyrinthodonts, and an increase in the temnospondyl and reptiliomorphan amphibians
Detritivores pervasive with herbivory beginning at the end of Mississippian