5.six.cuatro Sacral spinal vertebrae
Multiple separated sacral centra was indeed gathered (age.g., PEFO 33875 and you may 33819), although sacral rib and you can neural arch is damaged out-of. Exactly how many sacral vertebrae is decided are one or two established on: (a) a couple of collection of sacral rib markings into ilia regarding Roentgen. callenderi; (b) a few ankylosed centra (PEFO 36876) which have obvious articulations getting ribs and you can sensory arches (Rates 8i–k); and you may (c) there be seemingly simply a couple of morphologies away from sacral vertebrae certainly new isolated specimens. Both ankylosed centra reveals that certain specimens away from Roentgen. callenderi get coossify the sacral backbone which that it profile was variable for the taxon. While the all specimens out of PFV 297 is away from comparable size, it coossification in certain specimens will not seem to be proportions related. Rather, just like the during the ventral view the horizontal expansions of centra to the newest ankylosed city commonly well shaped, so it combination you will definitely show an effective pathology and extra specimens are expected to confirm it.
The new sacral centra is elongate and you will mediolaterally wider than dorsoventrally high, as well as the centrum faces is actually amphicoelous (Numbers 8i–k). Next sacral http://datingranking.net/tr/christiancafe-inceleme/ rib articulates with many of one’s lateral facial skin of your own centrum and you can part of the ventrolateral body of one’s neural arc (PEFO 36876). For the dorsal view, the sacral rib of second sacral vertebra increases considerably for the an enthusiastic anteroposteriorly elongate articulation to the ilium (Shape 8l). Within the horizontal view, it articulation skin is cigar-shaped; which articulates with most of period of the fresh postacetabular process of your ilium. New prior part of the articulation is slightly convex with a great limited dorsomedial extension. The rest of the articular body is concave. The latest articular epidermis of centrum therefore the 2nd sacral rib is rounded in lateral consider (Profile 8k). A transverse ridge distinguishes the new articular facial skin towards the two fold, a lesser part that meets for the a position on the lateral region of the 2nd sacral centrum, and a higher area you to definitely articulates to the sensory arc. The brand new sensory arch is not well-preserved in any sample; the fresh prezygapophysis are situated 60° of horizontal plus the postzygapophysis are centered simply 10° off lateral (regardless of if they might be somewhat crushed).
The full number of caudal spinal vertebrae found in Roentgen. callenderi is unfamiliar; yet not, discover in the 34–thirty-six caudal spinal vertebrae on the aetosaurian A beneficial. ferratus (J.B. Desojo, private communications, 2021), and you may an equivalent count might have been present in the brand new aetosauriform Roentgen. callenderi (Profile seven; Nesbitt, 2011 ; ).
5.6.5 Prior and you can mid-caudal spinal vertebrae
Anterior caudal backbone (Contour 8m) enjoys hourglass-shaped centra into the ventral check that will be anteroposteriorly longer than mediolaterally wider and you may significantly grooved ventrally (elizabeth.grams., PEFO 34561). This groove expands in the prior and you can posterior stops which is noted by the type of ridges. Brand new prior prevent merges with a couple of posteriorly more inclined face, and this serve as brand new articulation surfaces on chevrons. These types of change from the new hook up-such as for instance chevron facets of particular rauisuchids (age.g., UCMP 124890; Long & Murry, 1995 : fig. 130c). Since the anteriormost caudal vertebra is not managed, this is not obvious at which position the chevrons start. The brand new articular faces are bullet and you will amphicoelous having evident wheels. The neural arc try low, or around half of the new top of centrum articular deal with. This new prezygapophysis was really-install forming a great posteroventrally, and you will medially depending flat articular surface. The fresh new distal margins off both prezygapophyses combine together and are usually confluent into anterior edge of the fresh new neural spine. The fresh new back try anteroposteriorly wide with a level rear boundary and you can an enthusiastic anteroventrally slanting anterior border. This new apex is not longer for the a proper-create back table. The fresh new postzygapophysis is a lot tall (more or less twice new peak) as compared to prezygapophysis. Their horizontal margin is virtually straight, while the articular skin was inclined ventromedially regarding the 45° and you may face quite posteriorly.