The ossicular chain of Cainotheriidae (Mammalia, Artiodactyla).

This work describes an unparalleled sample of isolated fossil auditory ossicles of cainotheriid artiodactyls from the Paleogene karstic infillings of Dams (Tarn-et-Garonne, Quercy, France). This collection comprises a total of 18 mallei, 28 incudes and three stapedes. It allows the documentation of both intra- and interspecific variability of ossicular morphology within Cainotheriidae. We show that despite considerable intraspecific variability, the malleus, the incus and the stapes appear to be taxonomically informative at the Cainotheriidae scale. This work further provides the first description of a reconstructed ossicular chain of a terrestrial Paleogene artiodactyl species, found in a basicranium of the late Oligocene cainotheriine Caenomeryx filholi (Pech Desse locality).