Hook ridge to the posterodorsal margin of dorsal techniques articulates in a slot into the anteroventral osal. Rear to that particular there’s a low fossa which is overlapped from the anterolateral side of the newest quadrate. The new ventral tip of fossa is the prior border out-of the brand new quadrate foramen. New posteroventral corner of quadratojugal forms a continuous epidermis which have the latest lateral portion of the quadrate, installing for the a beneficial fossa to the horizontal margin of second ability. This new quadratojugal versions the brand new posteroventral part of the horizontal temporal fenestra during the Roentgen. callenderi.
Anteriorly, the brand new tapered posterior procedure for the fresh jugal inserts with the an effective triangular slot into the horizontal epidermis of the quadratojugal (Profile 4o). This form of articulation is also contained in P. kirkpatricki (TTU P-9002; Weinbaum, 2011 : fig. 13). An identical articulation design takes place in An excellent. ferratus and Paratypothorax andressorum (SMNS 19003; Schoch & Desojo, 2016 ) amino ek??i, where a sub-triangular posterior procedure of the brand new jugal inserts towards the a keen embayment within the this new anteroventral margin of quadratojugal ventral on the lateral temporary fenestra. During these taxa, a little anteroventral process of brand new quadratojugal underlaps brand new jugal (Schoch, 2007 ). The same articulation as well as takes place in the fresh new doswelliid archosauriform Rugarhychos sixmilensis (Wynd et al., 2020 ) suggesting so it reputation state is generally plesiomorphic.
The postorbital try a good triradiate limbs having a keen ornamented lateral body and you can three distinctive line of process (Data 4q, r). The anterodorsal techniques has a definite horizontal slot you to gets the ventral and you can posterior portion of the postfrontal, the brand new posterodorsal processes articulates on anterodorsal osal, and the ventral procedure suits on a position towards the prior and you can medial epidermis of one’s posterodorsal means of the latest jugal. The brand new dorsal margin is broadly curved and has now a distinct ridge one forms the newest anterolateral margin of the supratemporal fenestra. The fresh new curved prior margin features a weaker ridge, developing new posterodorsal margin of one’s orbit. The strong dorsal ridge, and that stretches posteriorly onto the squamosal, isn’t utilized in aetosaurs (age.g., Desmatosuchus smalli, TTU P9024-; T. coccinarum, PEFO 38001). It is very probably missing from inside the Good. geoffreyi (UCMP 156046), hence does not maintain brand new postorbital, but has the fresh squamosal and lacks that it ridge. D. grallator enjoys the same dorsal ridge on postorbital and you can squamosal (Sues et al., 2003 ).
The newest anteroventral part of the squamosal and posterodorsal procedure for the fresh jugal almost meets across the posteroventral side of the brand new postorbital, nearly excluding that it feature off participation regarding the horizontal temporary fenestra (Contour 3b). So it close exception is not book so you can Roentgen. callenderi since it also takes place in P. kirkpatricki (Weinbaum, 2011 ), and participation may be very restricted when you look at the aetosaurs (e.g., A. ferratus) while the crocodylomorph D. grallator (Nesbitt, 2011 ; Schoch, 2007 ).
The new triangular ability to begin with interpreted just like the lacrimal of the Parker ainsi que al. ( 2005 : fig. 2) is actually an isolated postorbital recovered towards skull regarding PEFO 33787. The brand new anterior part of the left squamosal from inside the Parker et al. ( 2005 : fig. 2b) is largely a keen articulated postorbital.
The latest quadrate is preserved from inside the PEFO 34561 (Shape 4s, t), while the quadrates is blurry inside PEFO 38609 (Numbers 3c, d). The newest quadrate body’s a good, dorsoventrally extreme bones you to definitely does not have fenestration and you will slopes posteroventrally, differing throughout the condition in shuvosaurids and you may aetosaurs where in actuality the quadrate hills anteroventrally (Nesbitt, 2007 ).
A deep dorsoventrally situated fossa exists posterolateral into the lateral flange (Figure 4s). The newest pterygoid flange isn’t better-maintained when you look at the PEFO 34561, however the thickened base of the flange happen on the right element merely dorsal for the medial condyle along the medial boundary of the quadrate.