Data from: Body length of bony fishes was not a selective factor during the biggest mass extinction of all time

The Permo-Triassic mass extinction devastated life on land and in the sea,
but it is not clear why some species survived and others went extinct. One
explanation is that lineage loss during mass extinctions is a random
process in which luck determines which species survive. Alternatively, a
phylogenetic signal in extinction may indicate a selection process
operating on phenotypic traits. Large body size has often emerged as an
extinction risk factor in studies of modern extinction risk, but this is
not so commonly the case for mass extinctions in deep time. Here, we
explore the evolution of non-teleostean Actinopterygii (bony fishes) from
the Devonian to the present day, and we concentrate on the Permo-Triassic
mass extinction. We apply a variety of time-scaling metrics to date the
phylogeny, and show that diversity peaked in the latest Permian and
declined severely during the Early Triassic. In line with previous
evidence, we find the phylogenetic signal of extinction increases across
the mass extinction boundary: extinction of species in the earliest
Triassic is more clustered across phylogeny compared to the more randomly
distributed extinction signal in the late Permian. However, body length
plays no role in differential survival or extinction of taxa across the
boundary. In the case of fishes, size did not determine which species
survived and which went extinct, but phylogenetic signal indicates that
the mass extinction was not a random field of bullets.