Data from: Ecological continuity and transformation after the Permo-Triassic mass extinction in northeastern Panthalassa

The Permo-Triassic mass extinction (PTME) is often implicated in the
transition from the Paleozoic Evolutionary Fauna (PEF) to the Modern
Evolutionary Fauna (MEF). However the exact timing and details of this
progression are unknown, especially regarding the vacating and filling of
functional ecological space after the PTME. Here we quantify the
functional diversity of middle Permian and Early Triassic marine
paleocommunities in the western US to determine functional re-organization
in the aftermath of the PTME. Results indicate that while the PTME was
selective in nature, many new Triassic taxa either re-filled functional
roles of extinct Permian taxa or performed the same functional roles as
Permian survivors. Despite this functional overlap, Permian survivors and
new Triassic taxa differed significantly in their relative abundances
within those overlapping functions. This shift in numerical emphasis,
driven by an increase in abundance towards more MEF-style traits, may
represent a first step in the transition between the PEF and MEF. We
therefore suggest that the extreme impact of the PTME had significant and
permanent re-organizational effects on the intrinsic structure of marine
ecosystems. Early Triassic ecosystems likely bridged the gap between the
Paleozoic and Modern Evolutionary Faunas, as newly originated Triassic
taxa shared ecospace with Permian survivors, but shifted functional
emphasis.