The parasphenoid and basisphenoid are fused, except for the most anterior / dorsal end of the fused bones, in which there is a slight separation in the trabecular attachment of the basisphenoid.
12.
The parasphenoid and basisphenoid are fused, except for the most anterior / dorsal end of the fused bones, in which there is a slight separation in the trabecular attachment of the basisphenoid.
13.
The vacuities in " Reithrodon ", formerly considered a phyllotine, are especially large . " Nyctomys " is special in having sphenopalatine vacuities restricted to the basisphenoid bone.
14.
In " Chaohusaurus " the width of basisphenoid is about 63 % of its length . " Chaohusaurus " has a combination of more pointed and bulbous teeth, that was probably separately evolved.
15.
The placement of " Itilochelys rasstrigin " in the family Cheloniidae is supported by the contact of the squamosal and parietal bones, an emarginated v-shaped crest on the underside of the basisphenoid, and features of the nasal bone structure.
16.
This specimen can be distinguished from " " A . magnus " " in having three exits for " N . hypoglossus " ( XII ) instead of two, by the lesser angle between ventral surfaces of basisoccipital and basisphenoid, and by the more caudally situated basispterygoid processes.
17.
The palatine bone and quadrate or to the articular extremity of the mandible; the pterygoid is connected with the maxillary by the ectopterygoid or transverse bone, which may be very long, and the maxillary often emits a process towards the palatine, the latter bone being usually produced inwards and upwards towards the anterior extremity of the basisphenoid.
18.
Defining characteristics of " Slaugenhopia " include a notch in the pterygoid bone of the palate called the pterygoid incisure; the wideness of a projection of bone in the palate called the cultriform process, a wide contact between the parasphenoid and basisphenoid bones on the underside of the skull, and uniquely " L "-shaped postparietal bones at the back of the skull.
19.
It's fossils are the most complete of any ichthyosaur in the Canadian Arctic . " A . chrisorum " has several features that separate it from the genus " Ophthalmosaurus ", including a highly angled articulation between the radius and ulna and the humerus and a foramen for the internal carotid artery ( a major artery that supplies blood to the brain ) on the posterior surface of the basisphenoid.
20.
A large hole may be present between the frontal bones and the basisphenoid ( Psammophis, Coelopeltis ); the maxillary may be much abbreviated and movable vertically, as in the Viperidae; the pterygoids may taper and converge posteriorly, without any connection with the quadrate, as in the Amblycephalidae; the supratemporal may be much reduced, and wedged in between the adjacent bones of the cranium; the quadrate may be short or extremely large; the prefrontals may join in a median suture in front of the frontals; the dentary may be freely movable, and detached from the articular posteriorly.
