5.6.4 Sacral spinal vertebrae
Several remote sacral centra was in fact compiled (e.grams., PEFO 33875 and you can 33819), although sacral rib and you will neural arch was damaged off. Exactly how many sacral backbone is set becoming several mainly based on: (a) several distinct sacral rib markings toward ilia out of R. callenderi; (b) two ankylosed centra (PEFO 36876) which have obvious articulations for ribs and you can sensory arches (Rates 8i–k); and you may (c) around appear to be simply two morphologies regarding sacral vertebrae one of new remote specimens. Both ankylosed centra demonstrates certain specimens from Roentgen. callenderi could possibly get coossify their sacral backbone hence that it reputation are variable in the taxon. Once the all specimens out of PFV 297 try regarding comparable size, this coossification in certain specimens doesn’t seem to be proportions associated. Instead, as during the ventral look at the horizontal expansions of your centra to the fresh ankylosed town commonly very well symmetrical, this mix you may portray a cystic and extra specimens are required to confirm which.
This new sacral centra are elongate and you may mediolaterally broad than simply dorsoventrally significant, therefore the centrum confronts was amphicoelous (Numbers 8i–k). The next sacral rib articulates with most of one’s lateral body of the centrum and you can an element of the ventrolateral body of your own neural arc (PEFO 36876). In the dorsal consider, brand new sacral rib of next sacral vertebra expands greatly towards the a keen anteroposteriorly elongate articulation for the ilium (Shape 8l). Inside lateral check, that it articulation body try cigar-shaped; it articulates with a lot of of duration of the new postacetabular process of your own ilium. The new anterior part of the articulation is a little convex that have a good slight dorsomedial extension. The remainder articular epidermis try concave. The newest articular epidermis of the centrum in addition to 2nd sacral rib was rounded when you look at the horizontal glance at (Shape 8k). An effective transverse ridge separates this new articular skin on the two fold, a diminished area that meets towards the a slot toward horizontal side of the next sacral centrum, and an upper region one to articulates for the neural arch. This new neural arc is not really-managed in virtually any specimen; the newest prezygapophysis was dependent 60° regarding horizontal while the postzygapophysis is mainly based simply 10° out of horizontal (regardless if they are quite surface).
The complete number of caudal vertebrae within Roentgen. callenderi is actually not familiar; but not, you’ll find at 34–thirty-six caudal vertebrae regarding the aetosaurian A great. ferratus (J.B. Desojo, personal telecommunications, 2021), and a comparable number might have been found in the fresh aetosauriform https://datingranking.net/tr/blendr-inceleme/ R. callenderi (Shape seven; Nesbitt, 2011 ; ).
5.6.5 Anterior and you may mid-caudal spinal vertebrae
Anterior caudal vertebrae (Contour 8m) provides hourglass-shaped centra from inside the ventral evaluate which can be anteroposteriorly longer than mediolaterally wider and you will significantly grooved ventrally (e.g., PEFO 34561). That it groove expands from the anterior and you will posterior stops in fact it is noted from the collection of ridges. The fresh anterior prevent merges with a couple of posteriorly much more likely faces, hence serve as the fresh articulation counters to your chevrons. Such differ from the fresh connect-such as chevron facets of specific rauisuchids (e.grams., UCMP 124890; Much time & Murry, 1995 : fig. 130c). Given that anteriormost caudal vertebra isn’t maintained, it is not obvious at which position the chevrons begin. The fresh new articular confronts try bullet and amphicoelous which have evident wheels. The neural arch is reasonable, or just around half of the latest height of the centrum articular deal with. The new prezygapophysis are better-put up creating a good posteroventrally, and you can medially situated apartment articular body. This new distal margins off both prezygapophyses mix along with her and generally are confluent with the prior side of the new sensory lower back. The new back try anteroposteriorly large having a level rear line and you may an anteroventrally sloping anterior line. Brand new apex is not prolonged on the a proper-developed spine desk. The brand new postzygapophysis is a lot high (approximately twice brand new top) versus prezygapophysis. Its lateral margin is close to straight, therefore the articular facial skin try much more likely ventromedially from the 45° and face quite posteriorly.