5.6.cuatro Sacral spinal vertebrae
Numerous isolated sacral centra have been gathered (e.grams., PEFO 33875 and you may 33819), although sacral rib and sensory arc is busted away from. What amount of sacral vertebrae is set are a couple of mainly based on: (a) a couple of collection of sacral rib markings into ilia out of Roentgen. callenderi; (b) a couple of ankylosed centra (PEFO 36876) having obvious articulations getting ribs and you can sensory arches (Numbers 8i–k); and you will (c) there be seemingly merely two morphologies regarding sacral vertebrae certainly brand new separated specimens. Both ankylosed centra reveals that particular specimens out of Roentgen. callenderi may coossify its sacral vertebrae which which reputation was adjustable during the taxon. Given that all of the specimens of PFV 297 is regarding similar proportions, which coossification in a number of specimens does not seem to be dimensions related. As an alternative, because in the ventral view the lateral expansions of your own centra as much as the brand new ankylosed city commonly well shaped, this blend you certainly will depict a great pathology and extra specimens are needed to confirm so it.
The new sacral centra is elongate and you can mediolaterally wide than simply dorsoventrally extreme, and the centrum face is actually amphicoelous (Figures 8i–k). The following sacral rib articulates with a lot of of your horizontal surface of one’s centrum and you can the main ventrolateral body of one’s sensory arc (PEFO 36876). From https://datingranking.net/tr/chatrandom-inceleme/ inside the dorsal view, new sacral rib of your own second sacral vertebra expands considerably to your an enthusiastic anteroposteriorly elongate articulation on the ilium (Contour 8l). Inside lateral evaluate, that it articulation skin was cigar-shaped; which articulates with most of one’s period of new postacetabular techniques of one’s ilium. The fresh prior portion of the articulation are some convex which have good moderate dorsomedial expansion. Other articular surface was concave. The newest articular facial skin of your own centrum and also the second sacral rib is circular within the horizontal evaluate (Profile 8k). An excellent transverse ridge separates brand new articular surface on two fold, a lesser region that meets with the a slot into the lateral area of the next sacral centrum, and you may an upper part one articulates into the sensory arc. The brand new sensory arch is not well-managed in almost any specimen; the fresh new prezygapophysis is actually depending 60° out-of lateral additionally the postzygapophysis is mainly based only 10° away from lateral (whether or not these are typically slightly crushed).
The complete amount of caudal spinal vertebrae present in Roentgen. callenderi is unknown; however, discover at the 34–thirty six caudal vertebrae throughout the aetosaurian A good. ferratus (J.B. Desojo, private correspondence, 2021), and a similar count was found in the fresh new aetosauriform R. callenderi (Contour seven; Nesbitt, 2011 ; ).
5.six.5 Prior and mid-caudal spinal vertebrae
Prior caudal vertebrae (Figure 8m) possess hourglass-molded centra within the ventral glance at which might be anteroposteriorly more than mediolaterally broad and you can significantly grooved ventrally (e.g., PEFO 34561). Which groove expands on prior and you may rear finishes that is noted by distinct ridges. The brand new prior avoid merges having a couple posteriorly more likely face, which serve as the brand new articulation surfaces with the chevrons. Such change from the hook up-instance chevron facets of some rauisuchids (age.grams., UCMP 124890; Enough time & Murry, 1995 : fig. 130c). As the anteriormost caudal vertebra isn’t managed, that isn’t obvious at which position the chevrons initiate. New articular confronts was bullet and you will amphicoelous which have sharp wheels. The neural arch are reasonable, or about 50 % of the newest top of one’s centrum articular deal with. Brand new prezygapophysis are really-arranged developing good posteroventrally, and medially situated flat articular body. The fresh distal margins from one another prezygapophyses blend together with her and are generally confluent towards prior edge of the newest neural back. The fresh back are anteroposteriorly wider which have a level rear boundary and you can an anteroventrally slanting anterior line. The fresh top is not prolonged towards a properly-build spine dining table. The fresh new postzygapophysis is significantly large (approximately double new height) versus prezygapophysis. Their lateral margin is practically straight, and articular surface is actually more likely ventromedially in the forty five° and face slightly posteriorly.