5.six.cuatro Sacral spinal vertebrae

Numerous separated sacral centra was in fact built-up (e.grams., PEFO 33875 and you may 33819), nevertheless sacral rib and sensory arch try broken off. The number of sacral spinal vertebrae is determined are a couple of situated on: (a) a couple of distinct sacral rib markings into ilia regarding Roentgen. callenderi; (b) two ankylosed centra (PEFO 36876) having obvious articulations to possess ribs and you will neural arches (Rates 8i–k); and you may (c) there seem to be just a couple morphologies out-of sacral backbone one of the fresh isolated specimens. The 2 ankylosed centra reveals that some specimens of Roentgen. callenderi will get coossify their sacral vertebrae which this reputation is changeable into the taxon. As the all the specimens away from PFV 297 are regarding comparable dimensions, it coossification in a few specimens does not appear to be dimensions related. Rather, once the from inside the ventral look at the horizontal expansions of one’s centra as much as the ankylosed urban area commonly very well symmetrical, so it combination you may portray a great cystic and extra specimens are expected to confirm that it.

The new sacral centra are elongate and you can mediolaterally wider than just dorsoventrally tall, therefore the centrum confronts was amphicoelous (Numbers 8i–k). The following sacral rib articulates with most of your lateral surface of your centrum and an element of the ventrolateral facial skin of neural arch (PEFO 36876). In the dorsal take a look at, the brand new sacral rib of one’s second sacral vertebra develops greatly for the an anteroposteriorly elongate articulation into ilium (Contour 8l). During the horizontal view, which articulation skin is cigar-shaped; which articulates with most of the duration of the newest postacetabular processes of one’s ilium. The new anterior part of the articulation is a little convex having a beneficial slight dorsomedial expansion. Other articular body was concave. The fresh articular facial skin of the centrum plus the second sacral rib are circular in lateral see (Profile 8k). A good transverse ridge distinguishes new articular epidermis for the two-fold, a reduced part that suits into the a position on the lateral region of the second sacral centrum, and a higher area one to articulates with the neural arc. New sensory arch isn’t really-managed in almost any sample; the newest prezygapophysis is depending sixty° of horizontal and postzygapophysis is actually oriented simply ten° from horizontal (regardless if these are generally somewhat crushed).

The complete amount of caudal backbone contained in Roentgen. callenderi was not familiar; not, you will find at 34–thirty six caudal vertebrae throughout the aetosaurian An effective. ferratus (J.B. Desojo, personal communication, 2021), and a similar matter was contained in the new aetosauriform Roentgen. callenderi (Profile 7; Nesbitt, 2011 ; ).

5.6.5 Prior and you can mid-caudal vertebrae

Anterior caudal vertebrae (Contour 8m) has actually hourglass-shaped centra within the ventral take a look at which can be anteroposteriorly longer than mediolaterally wide and you will significantly grooved ventrally (e.grams., PEFO 34561). So it groove grows on prior and you can posterior stops which can be noted of the collection of ridges. New prior avoid merges having one or two posteriorly more likely face, and therefore serve as the fresh articulation surfaces towards chevrons. This type of change from the new hook-including chevron areas of specific rauisuchids (e.grams., UCMP 124890; A lot of time & Murry, 1995 : fig. 130c). As anteriormost caudal vertebra is not preserved, this isn’t clear at which place the chevrons initiate. Brand new articular confronts was round and you will amphicoelous with evident rims. The neural arc is reasonable, or around 50 % of the latest level of your centrum articular face. The brand new prezygapophysis try really-install developing an excellent posteroventrally, and medially mainly based apartment articular surface. The fresh new distal margins out of both prezygapophyses combine with her and are also confluent with the prior side of the newest neural spine. This new spine are anteroposteriorly wider which have a much posterior edge and a keen anteroventrally slanting anterior line. New apex isn’t lengthened with the a properly-developed lower back desk. The fresh postzygapophysis is significantly large (around double the brand new level) than the prezygapophysis. The horizontal brazilcupid Гјcretsiz margin is practically upright, in addition to articular skin try more likely ventromedially about 45° and faces slightly posteriorly.