Kansasiella eatoni

Kansasiella eatoni

Otic inner and dorsal surfaces are more completely preserved than in Phoebeannaia , revealing the semicircular canals, ampullae and details of the neurocranial roof. There is a small midline tectosynotic fossa (t.syn.f; Fig. 9D) between the posterior semicircular canals, and a long anterior dorsal fontanelle (ant.d.fon; Fig. 9D) that stretches forward to the level of the basipterygoid processes. An expansive fossa bridgei (f.br; Figs 7C, 9D) houses an anterior spiracular fossa (spir.f; Fig. 9D) and a deep posterior depression containing poorly ossified intermural diverticula that do not appear to enter the intracranial space. The spiracular bridge (spir.br; Figs 7C, 9C, D) is deeper and more obliquely angled than that of Phoebeannaia , extending anterodorsally from the base of the hyoid facet. The enclosed spiracular canal is narrower. The lateral commissure curves sharply in to meet the post-orbital processes, forming a more hooked shape in lateral view than the smooth taper of Phoebeannaia . The vestibular fontanelle and the posterior descending ventral tongue are proportionately smaller than in Phoebeannaia , and the projection for articulation with the first suprapharyngobranchial (art.1 st.s; Fig. 7C) is located more anteriorly. Our reconstruction is more detailed than prior depictions of the area surrounding the hyomandibular articulation, revealing a facet (hm.fa; Fig. 7C) like that of Phoebeannaia and clearly delimited from the adjacent spiracular bridge and parampullary fossa.

ORBITAL