The braincase is where "Protoavis" comes close to being as avian as Chatterjee has maintained. The otic capsule is allegedly organized in avian fashion, with three distinct foramina arranged as such: fenestra ovalis, fenestra pseudorotunda, and the caudal tympanic recess, with a bony metotic strut positioned between the fenestra pseudorotunda and caudal tympanic recess. The claim that the full complement of tympanic recesses seen in ornithurines, are similarly observed in "Protoavis" is questionable, as the preservation of the braincase is not adequate to permit concrete observations on the matter. Chatterjee omits in his 1987 account of the braincase, the presence of a substantial post-temporal fenestra, which in all Aves (including "Archaeopteryx"), is reduced or absent altogether, and the lack of a pneumatic sinus on the paroccipital. Furthermore, the braincase possesses multiple characters symplesiomorphic of Coelurosauria, including an expanded cerebellar auricular fossa, and a vagal canal opening into the occiput. What is preserved of the preorbital skull curiously lacks apomorphic characters to be expected in a specimen, which is allegedly more closely allied to Pygostylia than is "Archaeopteryx lithographica". Most telling is the complete absence of accessory fenestrae in the antorbital fossa, leading to maxillary sinuses.