Each other PEFO 34561 and PEFO 34269 preserve partial 2nd sacral vertebrae
5.6.4 Sacral backbone
Several separated sacral centra had been amassed (elizabeth.grams., PEFO 33875 and 33819), nevertheless sacral rib and you will sensory arc are busted out of. What amount of sacral backbone is determined to-be two dependent on: (a) a couple of distinct sacral rib scars towards ilia away from R. callenderi; (b) two ankylosed centra (PEFO 36876) which have obvious articulations to have ribs and you will neural arches (Figures 8i–k); and you can (c) there seem to be only several morphologies out of sacral backbone among the fresh new separated specimens. The 2 ankylosed centra shows that some specimens of Roentgen. callenderi may coossify their sacral spinal vertebrae and that it character is variable in the taxon. Due to the fact the specimens out of PFV 297 is actually of comparable size, it coossification in a few specimens will not seem to be www.datingranking.net/tr/chathour-inceleme proportions associated. As an alternative, while the when you look at the ventral view the horizontal expansions of your centra doing this new ankylosed town aren’t perfectly symmetric, it combination you certainly will portray a beneficial pathology and additional specimens are needed to confirm it.
The latest sacral centra was elongate and you may mediolaterally wide than simply dorsoventrally significant, therefore the centrum confronts is actually amphicoelous (Numbers 8i–k). Next sacral rib articulates with many of the lateral surface of centrum and part of the ventrolateral surface of the neural arc (PEFO 36876). Inside the dorsal check, the newest sacral rib of 2nd sacral vertebra grows significantly to the a keen anteroposteriorly elongate articulation towards the ilium (Profile 8l). For the horizontal glance at, which articulation body are cigar-shaped; so it articulates with a lot of of length of this new postacetabular processes of your own ilium. The latest anterior part of the articulation was some convex having an effective limited dorsomedial extension. Other articular epidermis was concave. The articular body of your own centrum therefore the second sacral rib is actually game from inside the lateral look at (Figure 8k). An excellent transverse ridge separates the newest articular body on two parts, a lesser area that fits towards the a position into the lateral side of the 2nd sacral centrum, and you will a top region one to articulates to your neural arch. Brand new sensory arch is not better-kept in virtually any sample; brand new prezygapophysis try depending sixty° off horizontal and postzygapophysis try mainly based just 10° regarding lateral (regardless of if they’ve been quite surface).
The total level of caudal backbone within Roentgen. callenderi are not familiar; yet not, there are from the 34–thirty-six caudal vertebrae in the aetosaurian A good. ferratus (J.B. Desojo, individual telecommunications, 2021), and an equivalent count was contained in the fresh aetosauriform Roentgen. callenderi (Contour eight; Nesbitt, 2011 ; ).
5.6.5 Anterior and you will mid-caudal vertebrae
Anterior caudal spinal vertebrae (Shape 8m) has hourglass-designed centra inside ventral glance at which might be anteroposteriorly longer than mediolaterally greater and deeply grooved ventrally (elizabeth.g., PEFO 34561). This groove develops at anterior and you will rear closes which will be marked by the type of ridges. The newest anterior stop merges with a few posteriorly much more likely faces, which serve as the newest articulation counters towards the chevrons. Such range from the brand new hook-instance chevron elements of particular rauisuchids (e.g., UCMP 124890; A lot of time & Murry, 1995 : fig. 130c). Since anteriormost caudal vertebra isn’t preserved, this is simply not clear at which place the chevrons begin. The brand new articular faces is round and you may amphicoelous having evident tires. Brand new neural arc was lowest, or about 50 % of the newest top of centrum articular face. The prezygapophysis try well-put up forming a great posteroventrally, and you will medially created apartment articular facial skin. New distal margins away from each other prezygapophyses merge with her and are confluent on the prior edge of new neural lower back. The new back is anteroposteriorly wider that have a level posterior boundary and you will an anteroventrally sloping prior edge. The fresh new top isn’t extended with the a well-put up lower back desk. The newest postzygapophysis is significantly taller (more or less twice the brand new peak) compared to the prezygapophysis. Its lateral margin is close to straight, and articular body was more inclined ventromedially about 45° and you may confronts somewhat posteriorly.