Moscovian

From Palaeos.org

The Moscovian is in the ICS geologic timescale a stage or age in the Pennsylvanian, the youngest subsystem of the Carboniferous. The Moscovian age lasted from 311.7 ± 1.1 to 306.5 ± 1.0 Ma,[2] is preceded by the Bashkirian and is followed by the Kasimovian. The Moscovian overlaps with the European regional Westphalian stage.

The great tropical rainforests of Euramerica supported towering lycopsids and a heterogeneous mix of vegetation. These Lycopsid dominated forests, altered landscapes by creating organic-rich anastomosing river systems with multiple channels and stable alluvial islands.

Animal species distribution was very cosmopolitan at this time with the same species existing everywhere across tropical Pangaea. Invertebrates were abundant and diverse. Terrestrial vertebrates were predominantly amphibians and a few basal amniotes (‘reptiles’). Amphibians were tied to waterside habitats and were primarily piscivores, though a few had evolved insectivory. Almost unnoticed amongst the tetrapods, an important event was taking place. Alongside the Protorothyridid Captorhinids (Eureptilia), and barely distinguishable from them, was the earliest known Pelycosaur (Synapsida), Archaeothyris. The interplay between these two great divisions of amniotes - the Sauropsida (or Eureptilia) and the Theropsida (or Synapsida) will characterize tetrapod evolution up until the present day.

At the end of the Moscovian and continuing into the early Kasimovian, climate change affected the ecology of the rain forests resulting in a tree-fern dominated flora, replacing the lycopsids. The drier climate also affected amphibians resulting in a reduction in species, while the reptiles, better adapted to the drier conditions, diversified into more species.