15/08/2022
5.3 Mandible
Nearly the complete ana site mandible was illustrated inside the PEFO 34561 (Data 5d–j) and you will PEFO 38609 (Shape three-dimensional), including one another articulars, angulars, surangulars, splenials, and you may dentaries. callenderi.
5.3.step one Dentary
Over dentaries can be found during the PEFO 34561 (Contour 5d). White teeth are present toward anteriormost margin like the plesiomorphic reputation in the archosaurs and rather than brand new edentulous margin into the aetosaurs. The fresh dentary tooth number varies ranging from ten and 11. The brand new mesial-most alveoli have the tiniest diameter about feature and are generally slightly limited labiolingually; the alveolar diameters essentially improve distally. For the dorsal consider and you can doing mesially, the new tooth line curves medially so that it is lingual out-of new horizontal wall surface of the dentary. Enamel root try opened mostly on lingual area of the mandible and you can interdental plates occur. About regarding proper dentary off PEFO 34561, these are bonded regarding the mesial alveoli.
Anteriorly the brand new dentary tapers to help you a curved point in lateral view (Shape 5d). The fresh new weakly create dentary symphysis versions a rounded “mouth,” and also the ventral margin of your dentary was broadly circular close the new symphysis; it gets a sharper line so much more posteriorly. Short foramina shelter brand new horizontal skin of the prior part, and these reduced total of matter posteriorly. A-row of particularly higher foramina occurs close and you will synchronous in order to new dorsal margin; it is sometimes complicated to determine no matter if these have a great one-to-you to definitely connection with the fresh alveoli.
The medial surface was excavated by the good Meckelian groove that offers for most of the length of brand new function (Figure 5d). The groove are highest and you will greatest posteriorly, in which it covers around the whole medial section of the dentary, and you will constricts anteriorly, as a superficial groove around the new sixth dentary enamel and you can after that entirely disappears during the third otherwise last alveolus.
Posteriorly, around three type of tapered procedure offer not in the posterior margin of enamel line (Profile 5d). The fresh main and you may dorsalmost processes articulate with collection of grooves into anterolateral facial skin of surangular, whereas the low process matches towards the a good groove on anterolateral surface of your own angular. The essential dorsal and you can central processes group a keen anteriorly tapering sulcus into the horizontal body of one’s dentary that kept the main prior procedure on the surangular (pick lower than). The greater amount of dorsal process has actually a couple of preferred sharp ridges for the lateral skin; the fresh new dorsalmost one is proceeded having a lateral ridge to the surangular (select lower than). The latest central procedure talks about all of the or all of the area in which the brand new exterior mandibular fenestra is located in other archosaurs; ergo, the newest outside mandibular fenestra is smaller than average takes place ventral into the central process.
5.step 3.2 Surangular
The fresh surangular versions the newest dorsal area of the lateral wall surface regarding the hemimandible, and you will a beneficial rugose ornamentation covers the new lateral surface (Contour 5e). A-sharp ridge offers anteroposteriorly along side dorsolateral edge of the latest horizontal body (= surangular ridge) of surangular as with many other archosaurs, plus phytosaurs, P. kirkpatricki, A great. babbitti, and you will B. kupferzellensis (Gower, 1999 ; Nesbitt, 2005a , 2005b ; Stocker, 2012 ; Weinbaum, 2011 ).
This new prior edge of the brand new surangular have about three prior projections (Contour 5e). The newest main projection ‘s the premier and you may matches horizontal so you’re able to a keen anteriorly tapered sulcus within dorsal and you may main posterior procedure toward the latest dentary (find significantly more than). A deep concavity between the dorsal and central techniques of one’s surangular holds the fresh new dorsal rear projection on dentary. More ventral prior procedure for the latest surangular is set after that posteriorly along the ventral side of new ability and it has an excellent thin ventral flange that may were secure laterally by the angular.