Each other PEFO 34561 and you will PEFO 34269 maintain limited next sacral spinal vertebrae

5.six.cuatro Sacral spinal vertebrae

Multiple separated sacral centra was in fact compiled (e.g., PEFO 33875 and you will 33819), however the sacral rib and you will neural arch are busted out-of. Just how many sacral spinal vertebrae is decided is several built on: (a) a couple distinctive line of sacral rib scars toward ilia out-of R. callenderi; (b) a couple of ankylosed centra (PEFO 36876) that have clear articulations for ribs and you may sensory arches (Rates 8i–k); and you can (c) there seem to be only several morphologies off sacral backbone certainly the fresh new remote specimens. Both ankylosed centra demonstrates that certain specimens out-of R. callenderi could possibly get coossify its sacral vertebrae hence that it profile is actually changeable in the taxon. Once the most of the specimens out of PFV 297 are from comparable size, so it coossification in a few specimens does not seem to be proportions associated. Rather, since in the ventral look at the horizontal expansions of the centra doing the brand new ankylosed city commonly very well symmetrical, which combination you will definitely show an effective pathology and extra specimens are expected to confirm this.

The newest sacral centra try elongate and you will mediolaterally greater than just dorsoventrally tall, and the centrum faces was amphicoelous (Data 8i–k). Another sacral rib articulates with most of the horizontal facial skin of your centrum and you can an element of the ventrolateral body of sensory arc (PEFO 36876). From inside the dorsal have a look at, the latest sacral rib of your 2nd sacral vertebra increases significantly with the an enthusiastic anteroposteriorly elongate articulation to the ilium (Shape 8l). In lateral have a look at, so it articulation facial skin is actually cigar-shaped; it articulates with most of duration of the latest postacetabular techniques of your own ilium. This new anterior portion of the articulation try slightly convex having an excellent slight dorsomedial extension. All of those other articular epidermis was concave. The brand new articular skin of one’s centrum and next sacral rib try circular during the horizontal check (Figure 8k). An excellent transverse ridge distinguishes the fresh articular https://datingranking.net/tr/cougar-life-inceleme/ body on the two-fold, a lowered area that meets on a position into the lateral area of the next sacral centrum, and you can a top area that articulates into the sensory arc. New sensory arch is not better-maintained in every specimen; the new prezygapophysis are created sixty° regarding lateral and the postzygapophysis try founded simply 10° of lateral (no matter if they’re some ground).

The full quantity of caudal vertebrae found in Roentgen. callenderi was unfamiliar; however, you’ll find within 34–thirty-six caudal spinal vertebrae from the aetosaurian A good. ferratus (J.B. Desojo, individual interaction, 2021), and you can a comparable count might have been within new aetosauriform Roentgen. callenderi (Shape eight; Nesbitt, 2011 ; ).

5.six.5 Anterior and mid-caudal vertebrae

Prior caudal spinal vertebrae (Profile 8m) keeps hourglass-formed centra during the ventral view that are anteroposteriorly longer than mediolaterally large and you may significantly grooved ventrally (e.g., PEFO 34561). So it groove grows within prior and you can posterior finishes that is marked because of the type of ridges. The newest prior stop merges having two posteriorly more inclined confronts, which serve as the new articulation surfaces towards the chevrons. These types of range from the new connect-instance chevron areas of particular rauisuchids (age.grams., UCMP 124890; Long & Murry, 1995 : fig. 130c). Given that anteriormost caudal vertebra is not preserved, it is not obvious from which place the chevrons begin. This new articular confronts is round and you will amphicoelous with clear tires. The brand new neural arch try reduced, or about half the brand new height of your centrum articular face. Brand new prezygapophysis are better-build developing an excellent posteroventrally, and you may medially based flat articular surface. The fresh distal margins out-of one another prezygapophyses merge along with her and are generally confluent towards prior side of the new neural spine. The newest back is anteroposteriorly wider which have a much rear border and you may an enthusiastic anteroventrally slanting prior edge. The brand new top is not expanded for the a proper-developed spine table. New postzygapophysis is much taller (about twice the latest level) compared to prezygapophysis. Its lateral margin is virtually upright, and articular surface are inclined ventromedially about forty-five° and you will faces some posteriorly.