Print ISSN: 0031-0247
Online ISSN: 2274-0333
Werneburg et al. New Permian Caseid from France
Hypoplasia: CT-scan or naked eye?
Eocene otoliths (Clinchfield Formation), Georgia
New elephant cranium from early Pliocene Ileret, Kenya
Small sauropod tracks, Southern France
Fallen in a dead ear: intralabyrinthine preservation of stapes in fossil artiodactylsallometry; bony labyrinth; inner ear; middle ear ossicles
The stapes is the last of the middle ear ossicle chain and the smallest bone of the mammalian skeleton. Because it rests on the membrane of the fenestra vestibuli during life, the stapes may often fall within the bony labyrinth cavity when soft structures decay after death. In this work, we highlight the unexpected role that the bony labyrinth plays in the preservation of the stapes. Systematic investigation of the bony labyrinth of 50 petrosal bones of extinct and extant artiodactyls led to the discovery of eight cases of “intralabyrinthine” stapes. Three dimensional reconstructions of these stapes allow documenting stapes morphology of four extinct artiodactyl taxa: Microstonyx erymanthius (Suidae), Elomeryx borbonicus (Hippopotamoidea), ?Helohyus plicodon (Helohyidae), and an undetermined Cainotheriidae; and four extant ones Choeropsis and Hippopotamus (Hippopotamidae), and Tayassu and Phacochoerus (Suoidea). ?Helohyus plicodon from the Middle Eocene documents the oldest stapes known for the order Artiodactyla. Morphological study and metric analyses of our sample of artiodactylan stapes show that stapes are likely to carry relevant phylogenetic characters/signal within artiodactyls, and a potential Euungulata signature.
Published in Vol.40-1 (2016)