One consequence has been Romer's suggestion of the alternative order Younginiformes to be applied strictly to those forms with the primitive diapsid form, in particular, a complete lowermost arch as the quadratojugal and jugal bones of the skull meet.
22.
They are most easily distinguished from other crocodylians by their short premaxilla and maxillas, a transversely broad shelf on the jugal bone, and a pair of posterolaterally divergent ridges on the fossa on the jugal, and a leaf-shaped palatine bone.
23.
The squamosal bone at the back of the skull reaches forward to connect with the jugal bone behind the eye, forming a thin arch between the temporal fenestrae . " Myrmecodaptria " also has fewer and more widely spaced teeth in its jaws than do most other lizards.
24.
Based on this range of proportions, " Hoburogekko " may have been anywhere between long . " Hoburogekko " appears primitive in having an open Meckelian groove in the lower jaw that is open at the back and a it is inferred that had a large jugal bone beneath the eye socket, but it is similar to living geckos in having a frontal bone that forms a tube along the midline of the skull.
25.
Together these specimens provide details on most of the skeleton . " " A . " depressifrons " can be distinguished from all other species of " Asiatosuchus " by a combination of several characteristics including a large hole and a depressed area on the jugal bone of the skull, a frontal bone that does not touch the supratemporal fenestrae ( two holes at the top of the skull behind the eye sockets ), and a postorbital bone behind the eye socket that is visible when the skull is viewed from the side.
26.
However, " Myrmecodaptria " has many features that are not found in gekkotans, such as the presence of a small hole at the top of the skull called the parietal foramen, a thick jugal bone forming a complete postorbital bar behind the eye socket, and a complete upper temporal arch closing off a pair of holes at the top of the skull called the supratemporal fenestrae . " Myrmecodaptria " was again included in a phylogenetic analysis authored by Jack Conrad in 2008, which placed it in an extinct group called Bainguidae.
27.
More recently however a non-invasive ?CT scanning allowed for the examination of MB . R . 4520 and assessment of much of its internal basal archosauromorph ( based on the results of several phylogenetic analyses ), with a distinct back-side portion of the frontal bone, maxillary tooth row that extends behind the back margin of eye socket, a jugal bone with free back process, a palatine ramus of the pterygoid bone with shagreen of teeth, an angular bone exposed along about one third of the side surface of mandibular ramus, dichocephalous chest ribs, a notched front margin of the interclavicle, and a spoon-shaped back projection of the interclavicle.
