Hook ridge on the posterodorsal margin of the dorsal procedure articulates when you look at the a position on the anteroventral osal. Posterior to that particular there is certainly a low fossa that’s overlapped of the anterolateral edge of brand new quadrate. New ventral tip of fossa ‘s the prior border from new quadrate foramen. New posteroventral corner of the quadratojugal versions a continuous epidermis that have this new lateral part of the quadrate, installing for the a great fossa for the lateral margin of latter feature. The brand new quadratojugal variations the new posteroventral part of the horizontal temporal fenestra in the Roentgen. callenderi.
Anteriorly, the fresh new tapered rear procedure of the newest jugal inserts into the a triangular position on the lateral surface of one’s quadratojugal (Shape 4o). This style of articulation is also within P. kirkpatricki (TTU P-9002; Weinbaum, 2011 : fig. 13). A comparable articulation style occurs in Good. ferratus and you may Paratypothorax andressorum (SMNS 19003; Schoch & Desojo, 2016 ), in which a sub-triangular posterior procedure of this new jugal inserts on an embayment inside the the latest anteroventral margin of quadratojugal ventral towards the horizontal temporal fenestra. Within these taxa, a little anteroventral process of this new quadratojugal underlaps the newest jugal (Schoch, 2007 ). A comparable articulation including happens in the newest doswelliid archosauriform Rugarhychos sixmilensis (Wynd mais aussi al., 2020 ) indicating this profile county may be plesiomorphic.
The newest postorbital is an excellent triradiate bones with an enthusiastic ornamented horizontal skin and you may around three collection of procedure (Data 4q, r). The fresh new anterodorsal procedure have a distinct horizontal slot one to gets the ventral and you can posterior part of the postfrontal, the new posterodorsal techniques articulates to your anterodorsal osal, while the ventral process suits on a slot into the prior and you may medial facial skin of the posterodorsal procedure of the jugal. Brand new dorsal margin try generally curved and contains a definite ridge you to forms the brand new anterolateral margin of one’s supratemporal fenestra. The fresh new curved anterior margin provides a weaker ridge, developing the brand new posterodorsal margin of your own orbit. The fresh solid dorsal ridge, and that extends posteriorly onto the squamosal, is not included in aetosaurs (elizabeth.g., Desmatosuchus smalli, TTU P9024-; T. coccinarum, PEFO 38001). It is very most likely missing in An effective. geoffreyi (UCMP 156046), and this cannot keep brand new postorbital, but has the brand new squamosal and you can does not have that it ridge. D. grallator provides an identical dorsal ridge into postorbital and squamosal (Sues ainsi que al., 2003 ).
The brand new anteroventral portion of the squamosal and you will posterodorsal means of the brand new jugal nearly matches along side posteroventral side of the fresh new postorbital, almost leaving out which function out of contribution regarding the horizontal temporary fenestra (Profile 3b). It near different is not book to help you R. callenderi as it as well as takes place in P. kirkpatricki (Weinbaum, 2011 ), additionally the involvement is extremely minimal inside aetosaurs (e.g., A great. ferratus) and crocodylomorph D. grallator (Nesbitt, 2011 ; Schoch, 2007 ).
The latest triangular ability in the first place interpreted due to the fact lacrimal of the Parker ainsi que al. ( 2005 : fig. 2) is actually an isolated postorbital recovered on the head off PEFO 33787. The new prior portion of the leftover squamosal in Parker mais aussi al. ( 2005 : fig. 2b) is largely an enthusiastic articulated postorbital.
New quadrate was preserved during the PEFO 34561 (Figure 4s, t), in addition to quadrates is obscured inside PEFO 38609 (Numbers 3c, d). The brand new quadrate body is a substantial, dorsoventrally high bone one lacks fenestration and hills posteroventrally, differing in the symptom in shuvosaurids and you can aetosaurs where the quadrate hills anteroventrally (Nesbitt, 2007 ).
A deep dorsoventrally depending fossa is available posterolateral into the lateral flange (Profile 4s). The pterygoid flange is not better-managed during the PEFO 34561, although thickened foot of the flange takes place off to the right function just dorsal on medial condyle over the medial boundary of quadrate.