Text-fig. 7. Metacheiromys marshi, USNM-P 452349, basicranium isosurface from CT scans in oblique ventral view, showing middle ear ossicles as preserved. On the specimen's left side, the ossicles are essentially in life position, with the stapes largely hidden in the fenestra vestibuli; the left malleus is broken and represented largely by the mallear head. On the specimen's right side, most of the floor of auditory bulla has been removed to expose the malleus, which has shifted posteriorly from the life position. Abbreviations: aptt – anteroventral process of tegmen tympani, bo – basioccipital, bs – basisphenoid, eam – squamosal roof of external acoustic meatus, eo – exoccipital, gf – glenoid fossa, i – incus, m – malleus, mh – mallear head, oc – occipital condyle, pr – promontorium of petrosal, sh – stapedial head, tm – part of tubular external acoustic meatus. in Skeletal Anatomy Of The Basicranium And Auditory Region In The Metacheiromyid Palaeanodont Metacheiromys (Mammalia, Pholidotamorpha) Based On High-Resolution Ct Scans

Text-fig. 7. Metacheiromys marshi, USNM-P 452349, basicranium isosurface from CT scans in oblique ventral view, showing middle ear ossicles as preserved. On the specimen's left side, the ossicles are essentially in life position, with the stapes largely hidden in the fenestra vestibuli; the left malleus is broken and represented largely by the mallear head. On the specimen's right side, most of the floor of auditory bulla has been removed to expose the malleus, which has shifted posteriorly from the life position. Abbreviations: aptt – anteroventral process of tegmen tympani, bo – basioccipital, bs – basisphenoid, eam – squamosal roof of external acoustic meatus, eo – exoccipital, gf – glenoid fossa, i – incus, m – malleus, mh – mallear head, oc – occipital condyle, pr – promontorium of petrosal, sh – stapedial head, tm – part of tubular external acoustic meatus.