5.6.4 Sacral spinal vertebrae
Numerous isolated sacral centra was obtained (e.grams., PEFO 33875 and you can 33819), although sacral rib and you may sensory arch was damaged from. How many sacral spinal vertebrae is decided become several based on: (a) a few distinctive line of sacral rib marks towards ilia regarding Roentgen. callenderi; (b) two ankylosed centra (PEFO 36876) with obvious articulations to have ribs and neural arches (Rates 8i–k); and you may (c) indeed there seem to be merely a couple of morphologies away from sacral backbone one of the new isolated specimens. The two ankylosed centra implies that particular specimens of Roentgen. callenderi can get coossify their sacral spinal vertebrae and that so it character is variable from inside the taxon. Just like the most of the specimens of PFV 297 try of comparable proportions, this coossification in a number of specimens doesn’t appear to be proportions relevant. Instead, as within the ventral view the lateral expansions of the centra to the new ankylosed town are not very well symmetrical, so it combination you may show a good pathology and additional specimens are essential to verify so it.
Brand new sacral centra are elongate and you will mediolaterally wider than dorsoventrally significant, plus the centrum faces was amphicoelous (Numbers 8i–k). The next sacral rib articulates with many of the horizontal facial https://datingranking.net/tr/321chat-inceleme/ skin of one’s centrum and you may an element of the ventrolateral surface of your own sensory arch (PEFO 36876). During the dorsal view, the brand new sacral rib of your 2nd sacral vertebra expands considerably toward an anteroposteriorly elongate articulation into ilium (Shape 8l). Into the horizontal have a look at, this articulation body are cigar-shaped; it articulates with a lot of of your period of brand new postacetabular process of ilium. This new anterior part of the articulation are a bit convex with a beneficial limited dorsomedial expansion. Other articular surface is concave. The fresh new articular epidermis of centrum plus the 2nd sacral rib is round inside lateral check (Shape 8k). A transverse ridge distinguishes the new articular skin towards the two fold, a reduced region that fits for the a slot towards horizontal side of the second sacral centrum, and you may an upper area one to articulates toward neural arch. New neural arch isn’t well-preserved in almost any sample; new prezygapophysis are mainly based 60° of lateral together with postzygapophysis are created simply ten° of horizontal (regardless of if they have been a bit floor).
The entire level of caudal spinal vertebrae found in Roentgen. callenderi are unfamiliar; not, you will find at 34–36 caudal vertebrae regarding aetosaurian Good. ferratus (J.B. Desojo, private correspondence, 2021), and you may the same number was within this new aetosauriform Roentgen. callenderi (Figure 7; Nesbitt, 2011 ; ).
5.six.5 Prior and you will middle-caudal vertebrae
Prior caudal backbone (Contour 8m) have hourglass-designed centra within the ventral evaluate that will be anteroposteriorly longer than mediolaterally wide and profoundly grooved ventrally (e.grams., PEFO 34561). This groove increases from the anterior and you may rear closes and is noted from the type of ridges. This new prior avoid merges which have several posteriorly more likely face, and that serve as the articulation counters to the chevrons. Such change from the hook-such as for example chevron facets of particular rauisuchids (age.g., UCMP 124890; Long & Murry, 1995 : fig. 130c). While the anteriormost caudal vertebra is not kept, this isn’t obvious from which place the chevrons initiate. The fresh new articular face try bullet and you will amphicoelous with clear tires. The newest sensory arch is actually low, or just around 1 / 2 of the latest peak of one’s centrum articular deal with. This new prezygapophysis is actually well-set-up developing a beneficial posteroventrally, and you can medially centered apartment articular body. The fresh new distal margins away from both prezygapophyses mix together and they are confluent on the anterior side of the fresh neural spine. The fresh lower back is actually anteroposteriorly greater that have a level rear line and you will a keen anteroventrally sloping anterior edge. The apex isn’t offered to your a well-install lower back table. New postzygapophysis is a lot tall (around twice the fresh new top) than the prezygapophysis. Its horizontal margin is practically straight, and the articular skin is inclined ventromedially throughout the 45° and faces a bit posteriorly.