3D models related to the publication: The petrosal and bony labyrinth of Diplobune minor, an enigmatic Artiodactyla from the Oligocene of Western Europe

Abstract

Funding informationANR program SPLASH (ANR-15-CE32-0010-01) and to RA via the Fundação para a Ciência e Tecnologia fellowship SFRH/ BPD/96205/2013. This is ISE-M Publication no. ISEM 2017-004. AbstractAnoplotheriinae are Paleogene European artiodactyls that present a unique postcranial morphology with a tridactyl autopodium and uncommon limb orientation. This peculiar morphology led to various hypotheses regarding anoplotheriine locomotion from semiaquatic to partly arboreal or partly bipedal. The petrosal bone, housing the organs of balance, and hearing, offers complementary information to postcranial morphology on the ecology of this uncommon artiodactyl. Here, we investigate the middle ear and bony labyrinth of the small anoplotheriine Diplobune minor based on four specimens from the Early Oligocene locality of Itardies (Quercy, France). A macroscopic study coupled with a lCT scan investigation of the petrosal anatomy provides novel information on the bony labyrinth, stapes, and innervation and vasculature of the inner ear of this enigmatic taxon. The petrosal of D. minor exhibits a mosaic of plesiomorphic characters and peculiar features that shed new light into the anatomy of this poorly studied taxon of an obscure taxonomic clade. We can confidently reject that D. minor was a semiaquatic species based on the petrosal morphology: presence of a large mastoid process and nonpachyostotic tegmen tympani do not support underwater hearing. On the other hand, the average semicircular canal radius points to a slow or medium slow agility for D. minor, and fully rejects it was a fast moving animal, which is congruent with its postcranial anatomy. K E Y W O R D SAnoplotheriidae, bony labyrinth, lCT scan, Quercy, stapes

The petrosal and bony labyrinth of Diplobune minor, an enigmatic Artiodactyla from the Oligocene of Western Europe

“…Blood vessel canals and nerve pathways were also segmented as separate “labelfields” using AVIZO 9.0. The 3D‐models of the petrosals and bony labyrinths (Orliac, Araújo, & Lihoreau, ) are available in open access for visualization and download at http://MorphoMuseuM.com (DOI: ).…”

Virtual endocranial and inner ear endocasts of the Paleocene ‘condylarth’ Chriacus: new insight into the neurosensory system and evolution of early placental mammals

“…(AMNH VP 118359; Orliac & O'Leary, 2016;: fig. 2d) and in Diplobune minor (UM ITD 1081; Orliac et al, 2017: fig. 7c), the vena aquaeductus cochleae is a separate canal from the cochlear aqueduct in Ch.…”

“…(AMNH VP 118359; Orliac & O'Leary, : fig. 2d) or in Diplobune minor (UM ITD 1081; Orliac et al., : fig. 7c,d).…”

Petrosal and Basicranial Morphology of Leptoreodon major (Protoceratidae, Artiodactyla)

“…A similar ridge is present in several extant ruminants (Norris 2000), but its distribution among extinct ruminants has yet to be documented. Poebrotherium, a basal camelid, and anoplotheriids, a family of extinct endemic European artiodactyls, also appear to have this morphology (Dechaseaux 1969;Norris 2000;O'Leary 2010;Orliac et al 2017), and an endocranial ridge may be more common in artiodactyls than is currently known.…”

“…Based on this description, Leptoreodon and Protoceras have a similar bony labyrinth morphology. Both taxa share a vestibular aqueduct and cochlear aqueduct morphology that is typical of artiodactyls (e.g., Orliac et al 2012Orliac et al , 2017Mennecart and Costeur 2016a). Only the anterior semicircular canal was present in the described Protoceras specimen, but in both taxa, the anterior semicircular canal has a similar shape and lies in more than one plane (Robson et al 2021).…”