5.6.cuatro Sacral vertebrae
Several separated sacral centra were amassed (elizabeth.grams., PEFO 33875 and 33819), nevertheless sacral rib and sensory arch try broken of. The amount of sacral spinal vertebrae is set to get one or two mainly based on: (a) a couple of distinctive line of sacral rib marks to your ilia away from R. callenderi; (b) a couple of ankylosed centra (PEFO 36876) which have obvious articulations to have ribs and you can sensory arches (Figures 8i–k); and you may (c) around be seemingly simply several morphologies of sacral backbone certainly new separated specimens. The two ankylosed centra demonstrates that some specimens out of Roentgen. callenderi will get coossify its sacral backbone hence which character try adjustable during the taxon. Once the the specimens from PFV 297 is away from equivalent proportions, which coossification in certain specimens will not be seemingly dimensions associated. Instead, just like the inside ventral view the horizontal expansions of centra as much as the ankylosed urban area aren’t really well symmetrical, that it blend you’ll portray a good cystic and extra specimens are needed to verify which.
The latest sacral centra is actually elongate and you may mediolaterally wider than dorsoventrally tall, and centrum faces is actually amphicoelous (Rates 8i–k). The second sacral rib articulates with many of your lateral body of the centrum and you may an element of the ventrolateral body of your own neural arc (PEFO 36876). When you look at the dorsal look at, the newest sacral rib of the 2nd sacral vertebra increases significantly on the an anteroposteriorly elongate articulation with the ilium (Shape 8l). During the lateral look at, so it articulation body is cigar-shaped; which articulates with many of your own period of brand new postacetabular process of the ilium. The fresh new anterior part of the articulation try some convex that have good limited dorsomedial extension. The remainder articular surface try concave. The newest articular surface of your centrum together with 2nd sacral rib is circular inside lateral examine (Contour 8k). A transverse ridge separates the new articular epidermis toward two fold, a lesser part that suits towards the a position towards the lateral section of cougar life ekЕџi the next sacral centrum, and you will a top area you to definitely articulates towards the neural arc. Brand new neural arc isn’t better-maintained in any sample; the prezygapophysis is oriented 60° from lateral therefore the postzygapophysis try oriented simply ten° from lateral (even in the event these include slightly surface).
The full number of caudal spinal vertebrae found in R. callenderi is unknown; although not, discover in the 34–36 caudal vertebrae from the aetosaurian An effective. ferratus (J.B. Desojo, personal interaction, 2021), and you will a similar matter may have been present in this new aetosauriform Roentgen. callenderi (Contour seven; Nesbitt, 2011 ; ).
5.6.5 Prior and mid-caudal vertebrae
Anterior caudal backbone (Profile 8m) keeps hourglass-molded centra in ventral have a look at that will be anteroposteriorly longer than mediolaterally large and you can deeply grooved ventrally (e.g., PEFO 34561). This groove develops during the prior and you can rear ends and is marked by the distinctive line of ridges. The fresh prior prevent merges with two posteriorly much more likely face, and that act as the articulation surfaces toward chevrons. These types of range from the latest hook-instance chevron elements of specific rauisuchids (age.g., UCMP 124890; Enough time & Murry, 1995 : fig. 130c). Since anteriormost caudal vertebra is not kept, that isn’t clear from which put the chevrons initiate. Brand new articular face is bullet and amphicoelous with sharp wheels. The newest sensory arch was reduced, or about 1 / 2 of the latest level of one’s centrum articular deal with. Brand new prezygapophysis try really-set-up forming good posteroventrally, and you can medially established apartment articular epidermis. The latest distal margins away from both prezygapophyses combine together with her and generally are confluent on the prior edge of the fresh new sensory lower back. The fresh back was anteroposteriorly wider that have a much posterior line and you can an anteroventrally slanting anterior edge. New apex isn’t stretched into the a proper-install spine desk. New postzygapophysis is much taller (about twice the newest top) as compared to prezygapophysis. Their horizontal margin is virtually straight, and the articular surface try more inclined ventromedially regarding forty five° and you can faces somewhat posteriorly.