  The Eocene--Oligocene transition (EOT) represents a period of global
environmental changes particularly marked in Europe and coincides with a
dramatic biotic turnover. Here, using an exceptional fossil preservation, we
document and analyse the diversity dynamics of a mammal clade, Cainotherioidea
(Artiodactyla), that survived the EOT and radiated rapidly immediately after.
We infer their diversification history from Quercy Konzentrat--Lagerst{\"a}tte
(south-west France) at the species level using Bayesian birth--death models. We
show that cainotherioid diversity fluctuated through time, with extinction
events at the EOT and in the late Oligocene, and a major speciation burst in
the early Oligocene. The latter is in line with our finding that cainotherioids
had a high morphological adaptability following environmental changes
throughout the EOT, which probably played a key role in the survival and
evolutionary success of this clade in the aftermath. Speciation is positively
associated with temperature and continental fragmentation in a time-continuous
way, while extinction seems to synchronize with environmental change in a
punctuated way. Within-clade interactions negatively affected the cainotherioid
diversification, while inter-clade competition might explain their final
decline during the late Oligocene. Our results provide a detailed dynamic
picture of the evolutionary history of a mammal clade in a context of global
change.
