Each other PEFO 34561 and you will PEFO 34269 keep limited next sacral vertebrae
5.6.4 Sacral spinal vertebrae
Numerous isolated sacral centra was gathered (age.g., PEFO 33875 and you will 33819), but the sacral rib and you can neural arch are damaged off. Exactly how many sacral backbone is decided become one or two built on: (a) a few type of sacral rib marks towards the ilia out of R. callenderi; (b) a couple https://datingranking.net/tr/beautifulpeople-inceleme/ of ankylosed centra (PEFO 36876) having obvious articulations to possess ribs and you can sensory arches (Data 8i–k); and (c) indeed there seem to be just two morphologies regarding sacral spinal vertebrae one of the newest separated specimens. The 2 ankylosed centra implies that particular specimens of Roentgen. callenderi will get coossify the sacral vertebrae hence so it reputation is varying within the taxon. Because all of the specimens regarding PFV 297 are of similar dimensions, it coossification in a few specimens does not be seemingly dimensions relevant. As an alternative, because the in ventral view the lateral expansions of your centra doing the newest ankylosed area commonly really well shaped, which fusion you’ll represent a good pathology and extra specimens are required to confirm so it.
The new sacral centra is elongate and you may mediolaterally greater than dorsoventrally extreme, while the centrum face try amphicoelous (Data 8i–k). The following sacral rib articulates with many of your lateral skin of your centrum and you may a portion of the ventrolateral epidermis of sensory arc (PEFO 36876). Inside the dorsal evaluate, new sacral rib of your own 2nd sacral vertebra expands significantly to your an anteroposteriorly elongate articulation into ilium (Figure 8l). Inside the lateral see, which articulation epidermis is actually cigar-shaped; that it articulates with a lot of of length of new postacetabular procedure of your ilium. This new prior portion of the articulation is a bit convex that have a good moderate dorsomedial expansion. All of those other articular facial skin are concave. Brand new articular skin of one’s centrum therefore the 2nd sacral rib is game into the lateral check (Shape 8k). Good transverse ridge separates the new articular body into the two fold, a lowered region that fits into the a position to the lateral region of the second sacral centrum, and you can a higher part you to definitely articulates into the sensory arc. The new sensory arch is not well-preserved in any sample; new prezygapophysis is mainly based sixty° off horizontal and the postzygapophysis try built just ten° out of lateral (whether or not they have been a bit floor).
The amount of caudal backbone found in R. callenderi are unknown; yet not, discover in the 34–thirty-six caudal vertebrae regarding aetosaurian A beneficial. ferratus (J.B. Desojo, personal communications, 2021), and you may a comparable matter may have been within the new aetosauriform Roentgen. callenderi (Shape 7; Nesbitt, 2011 ; ).
5.six.5 Anterior and you will mid-caudal spinal vertebrae
Prior caudal spinal vertebrae (Profile 8m) has actually hourglass-molded centra for the ventral consider which might be anteroposteriorly more than mediolaterally broad and you may profoundly grooved ventrally (age.grams., PEFO 34561). Which groove develops at the anterior and rear concludes and that’s noted of the type of ridges. The prior avoid merges which have a couple posteriorly more inclined faces, and that serve as the fresh new articulation counters towards the chevrons. These types of change from this new connect-instance chevron aspects of certain rauisuchids (elizabeth.g., UCMP 124890; Enough time & Murry, 1995 : fig. 130c). As the anteriormost caudal vertebra is not maintained, it is not obvious where put the chevrons begin. The brand new articular confronts is actually round and you will amphicoelous that have sharp tires. The fresh new sensory arch is actually lowest, or about 50 % of the fresh peak of the centrum articular face. The prezygapophysis was better-set-up forming a good posteroventrally, and you may medially established flat articular surface. The brand new distal margins off both prezygapophyses blend together with her and they are confluent into the prior edge of the newest sensory back. The new back is actually anteroposteriorly broad having a much posterior line and you may an anteroventrally sloping prior line. Brand new top isn’t prolonged towards a proper-created lower back table. The newest postzygapophysis is much taller (more or less double this new height) as compared to prezygapophysis. Its lateral margin is virtually upright, in addition to articular skin is more likely ventromedially in the 45° and you will faces somewhat posteriorly.