Both PEFO 34561 and you can PEFO 34269 manage limited 2nd sacral vertebrae

5.6.cuatro Sacral vertebrae

Numerous separated sacral centra have been collected (e.g., PEFO 33875 and you may 33819), nevertheless sacral rib and you may neural arch try busted out of. How many sacral spinal vertebrae is decided become one or two centered on: (a) a couple of distinct sacral rib scars on the ilia from R. callenderi; (b) two ankylosed centra (PEFO 36876) with clear articulations to own ribs and sensory arches (Numbers 8i–k); and you will (c) here be seemingly merely a few morphologies from sacral spinal vertebrae certainly the new remote specimens. The two ankylosed centra demonstrates some specimens away from R. callenderi get coossify their sacral backbone and therefore it profile try variable from inside the taxon. Since the every specimens out of PFV 297 was from equivalent size, so it coossification in a few specimens does not seem to be dimensions related. As an alternative, while the inside ventral view the horizontal expansions of the centra to the latest ankylosed urban area are not perfectly symmetrical, which combo you certainly will portray a pathology and additional specimens are essential to confirm that it.

The latest sacral centra is elongate and you may mediolaterally greater than simply dorsoventrally tall, and centrum face are amphicoelous (Rates 8i–k). Next sacral rib articulates with many of the horizontal surface of your centrum and you can a portion of the ventrolateral body of one’s neural arc (PEFO 36876). Within the dorsal check, the fresh sacral rib of your 2nd sacral vertebra develops considerably with the a keen anteroposteriorly elongate articulation for the ilium (Shape 8l). Into the horizontal consider, this articulation facial skin is actually cigar-shaped; this articulates with most of amount of this new postacetabular procedure of one’s ilium. The new prior part of the articulation try slightly convex that have an effective limited dorsomedial expansion. The remainder articular skin are concave. The newest articular surface of one’s centrum together with second sacral rib is round during the lateral check (Shape 8k). A great transverse ridge separates the newest articular body with the two fold, a reduced area that fits to your a slot to the horizontal section of the second sacral centrum, and you can a higher region one to articulates for the sensory arch. The new sensory arc is not well-kept in just about any specimen; the new prezygapophysis was centered sixty° of lateral and also the postzygapophysis are dependent merely ten° out of horizontal (although they are a little surface).

The full quantity of caudal backbone contained in R. callenderi was unknown; although not, there are in the 34–thirty-six caudal spinal vertebrae about aetosaurian A great. ferratus (J.B. Desojo, private communications, 2021), and you can an identical number was within the fresh aetosauriform R. callenderi (Shape seven; Nesbitt, 2011 ; ).

5.6.5 Anterior and you can middle-caudal spinal vertebrae

Prior caudal spinal vertebrae (Figure 8m) has actually hourglass-designed centra in the ventral evaluate that will be anteroposteriorly more than mediolaterally large and you may seriously grooved ventrally (elizabeth.g, PEFO 34561). So it groove grows from the anterior and you will rear comes to an end that is noted from the line of ridges. New prior avoid merges which have a couple posteriorly inclined confronts, and therefore serve as the latest articulation counters towards the chevrons. This type of range from new link-such chevron areas of particular rauisuchids (age.g., UCMP 124890; A lot of time & Murry, 1995 : fig. 130c). Just like the anteriormost caudal vertebra is not maintained, that isn’t obvious of which position the chevrons initiate. The fresh new articular face is round and you can amphicoelous which have clear tires. New neural arch was low, or around 50 % of the brand new peak of centrum articular deal with. The fresh new prezygapophysis is actually really-setup developing a beneficial posteroventrally, and medially mainly based flat articular surface. The fresh distal margins out of both prezygapophyses combine with her and therefore are confluent for the prior edge of the brand new sensory lower back. The fresh new back is anteroposteriorly large that have a much posterior border and a keen anteroventrally slanting anterior edge. The top isn’t expanded on a highly-setup lower back desk. The fresh postzygapophysis is much tall (about double the fresh new peak) compared to prezygapophysis. Its horizontal margin is almost upright, in addition to articular skin is actually inclined ventromedially throughout the 45° and you will face a little posteriorly.