The new L-shaped quadratojugal is included sideways of the good rugose trend similar to that brand new squamosal and you will jugal (Shape 4o)

5.2.10 Quadratojugal

A small ridge with the posterodorsal margin of one’s dorsal process articulates during the a slot to the anteroventral osal. Posterior to this you will find a low fossa that’s overlapped from the anterolateral edge of the newest quadrate. Brand new ventral suggestion of your own fossa is the anterior border out-of the quadrate foramen. New posteroventral part of one’s quadratojugal versions an ongoing body having the fresh lateral part of the quadrate, suitable on the good fossa toward horizontal margin of one’s latter element. This new quadratojugal variations the latest posteroventral corner of the lateral temporary fenestra for the Roentgen. callenderi.

Anteriorly, the newest tapering posterior process of the new jugal inserts into the an effective triangular position into lateral skin of your quadratojugal (Contour 4o). This form of articulation is even found in P. kirkpatricki (TTU P-9002; Weinbaum, 2011 : fig. 13). The same articulation build occurs in Good. ferratus and you can Paratypothorax andressorum (SMNS 19003; Schoch & Desojo, 2016 ), where a sandwich-triangular posterior means of the newest jugal inserts towards a keen embayment for the brand new anteroventral margin of your quadratojugal ventral on the horizontal temporary fenestra. Within these taxa, a small anteroventral means of this new quadratojugal underlaps the jugal (Schoch, 2007 ). A comparable articulation also occurs in the doswelliid archosauriform Rugarhychos sixmilensis (Wynd et al., 2020 ) suggesting which profile condition is generally plesiomorphic.

5.dos.eleven Postorbital

The fresh new postorbital are a beneficial triradiate bone that have a keen ornamented lateral body and three distinct process (Figures 4q, r). The new anterodorsal processes have a distinct lateral slot you to definitely receives the ventral and posterior part of the postfrontal, the new posterodorsal procedure articulates into the anterodorsal osal, and also the ventral processes fits to the a position on the prior and medial body of the posterodorsal procedure for the fresh jugal. The latest dorsal margin try broadly rounded and has now a distinct ridge you to versions the new anterolateral margin of one’s supratemporal fenestra. The newest curved prior margin provides a weaker ridge, creating the latest posterodorsal margin of one’s orbit. The fresh good dorsal ridge, hence runs posteriorly on the squamosal, is not used in aetosaurs (age.grams., Desmatosuchus smalli, TTU P9024-; T. coccinarum, PEFO 38001). It is also most likely absent during the A beneficial. geoffreyi (UCMP 156046), and therefore does not preserve new postorbital, but comes with this new squamosal and you can does not have it ridge. D. grallator features an equivalent dorsal ridge into postorbital and squamosal (Sues et al., 2003 ).

The fresh new anteroventral portion of the squamosal and you may posterodorsal process of the brand new jugal nearly fits over the posteroventral side of the latest postorbital, almost leaving out this element away from involvement throughout the horizontal temporal fenestra (Contour 3b). This close different is not unique in order to R. callenderi since it plus happens in P. kirkpatricki (Weinbaum, 2011 ), and also the contribution may be very minimal inside the aetosaurs (age.g., A beneficial. ferratus) as well as the crocodylomorph D. grallator (Nesbitt, 2011 ; Schoch, 2007 ).

New triangular element to begin with interpreted because the lacrimal by the Parker ainsi que al. ( 2005 : fig. 2) is largely a remote postorbital retrieved on the head out-of PEFO 33787. The fresh new prior portion of the kept squamosal for the Parker et al. ( 2005 : fig. 2b) is actually an enthusiastic articulated postorbital.

5.dos.twelve Quadrate

Brand new quadrate is actually managed into the PEFO 34561 (Figure 4s, t), in addition to quadrates try blurry for the PEFO 38609 (Figures 3c, d). This new quadrate person is a solid, dorsoventrally significant bone you to definitely lacks fenestration and slopes posteroventrally, differing on the condition in shuvosaurids and aetosaurs in which the quadrate mountains anteroventrally (Nesbitt, 2007 ).

An intense dorsoventrally mainly based fossa can be obtained posterolateral on the lateral flange (Figure 4s). New pterygoid flange is not well-preserved in PEFO 34561, nevertheless thickened base of the flange happens on the right feature only dorsal into medial condyle over the medial edge of quadrate.

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