Detailed analysis of the stratigraphic ranges of Devonian rugose coral
genera within the Old World and Eastern Americas Realms gives new inf
ormation on faunal extinctions and other bioevents in both rearms. Var
ious origination and extinction metrics are calculated from tabulation
s of occurrences in each stage. The most significant faunal changes we
re near or at the ends of the Lochkovian and Frasnian stages. The form
er marks the gradual transition from dominance by Silurian families an
d genera to the characteristic Devonian coral assemblages; the latter
marks the virtual extinction of the Devonian families and genera. Othe
r coral events are related to the two major changes. The data provide
new bases for comparing the histories of the two realms. Most of the e
vents are recorded in both, giving support to previous suggestions tha
t the causes were worldwide. The coral record shows an increase (proba
bly episodic) in environmental deterioration persisting through the Mi
ddle Devonian and culminating in extinction at the end of the Frasnian
. Eustatic sea level fluctuations may have caused the precursor events
and a bolide impact may have caused the end-Frasnian extinction.