Figure 2.

Skull of Osteolaemus tetraspis (ROM R6533) illustrating the osteology of the MC of extant crocodyliforms. (A) Overview of the skull in lateral left view. (B) Detail of the posterior portion of the skull. (C) Detail of the posterior portion of the skull, with selected MC structures highlighted. Arrows indicate the extension of the sulcus for the attachment of the upper earlid. ADQ, anterodorsal process of the quadrate; BOA, bony otic aperture; DOI, dorsal otic incisure; EAM, external auditory meatus; IOC, incisure of the otic aperture of the cranioquadrate passage; MC, meatal chamber; OB, otic buttress; OI, otic incisure; PO, postorbital bone; QJ, quadratojugal; POF; periotic fossa; SF, subtympanic foramen; SQ, squamosal bone. Scale bars: 2 cm.