The pterygoids join anterior to the posterior interpterygoid vacuities, covering the
parasphenoid, as in most of the brachauchenine pliosaurids (Williston, 1903; Schumacher et al., 2013; Benson and Druckenmiller, 2014; Paramo-Fonseca et al., 2016).
From the region of the
parasphenoid bone (the parasphenoidale) we highlight the projection of the rostro-parasphenoidal (Rostrum parasphenoidale--RP, Figures.
The
parasphenoid is a triradial bone observed in the anterior region of the pituitary fenestra.
The rostral extremity (basi rostri parasphenoidalis, PjP, Figures 10-14) of the
parasphenoid region (PS, Figure 10) is larger and more rounded in N.
The third synapomorphy concerns the presence of a 'tongue-bite mechanism' with dorsal teeth on
parasphenoid, a feature that is homoplasy free within the fishes examined (261: 0 [right arrow] 1).
[7] Anterolateral process of
parasphenoid (Costa 1998a) (CI: 0.16; RI: 0.78): (0) short, free; (1) long, attached to pterosphenoid.
owstoni: "Cranium thin and papery; interorbital space and occiput flat, the former about 3.3 times in base of the cranium; preocular, postocular, tympanic and parietal spines present, but small and weak; nuchal spines sometimes present; supraocular and coronal spines absent; cranial ridges absent except for the parietal ridges which are low but never scaled over; parietals separated; mesethmoid processes never directed upward; base of cranium markedly curved; ventral process of basisphenoid feeble, never attached to the
parasphenoid; nasal spines low, but strong; preorbital lobes without spines; second suborbital bone much wider than long.
The toothplates consist of two elements; the basibranchial and
parasphenoid. The plates described herein are similar to those tentatively referred to Casierius heckelii by Huggins (1990) from the Trinity Group.
This character is problematic as the definition of '
parasphenoid wings' is not clear.
Vertical, complete laminar bony connection mesially to the eye between frontal, dorsally, and
parasphenoid, ventrally.
Anatomical abbreviations are:a-a, angular-articular; bo, basioccipital; de, dentary; fr, frontal; fv, facet on maxilla for articulation with vomer; ipr, internal (anterior) process of the maxilla; le, lateral ethmoid; mpr, maxillary (posterior) process of the maxilla; rex, maxilla(e); ha, nasal; nc, nutrient canal; pa,
parasphenoid; pd, predentary; pmx, premaxilla(e); pn, prenasal; pop, preopercle; pt, pterygoid; qu, quadrate; sph, sphenotic; tr, triangular region of maxilla; vo, vomer.