5.6.dos Postaxial cervical vertebrae
PEFO 34561 will not uphold any article-axial anterior cervical backbone, and this description primarily is based on PEFO 33861, PEFO 34269, and you may PEFO 34833 (Profile 8e). The fresh centra was anteroposteriorly brief; the fresh anteroposterior amount of the brand new centrum was a couple-thirds the level. The fresh new diapophysis is for the dorsolateral body of the centrum while the latest parapophysis is located for the ventrolateral facial skin. Among you can find moderately so you can really-developed non-pneumatic fossae. Ventrally, all of the centra has better-arranged keels. This new sensory arc and you may spine try dorsoventrally taller than the centrum; testing of PEFO 33861 and you will PEFO 34833 shows that the sensory spine screens self-confident allometry relative to brand new centrum. The fresh new neural spine are posteriorly put and a bit overhangs the fresh centrum. It is sideways compacted and you may anteroposteriorly narrow, with a highly limited expansion during the dorsal idea. The latest zygapophyses is actually created 50°–55° of lateral. The new postzygapophysis and it has a proper-set up epipophysis by way of at the least the newest last cervical vertebra (based on PEFO 34833). The current presence of article-axial epipophyses is very important because this character possess a restricted delivery when you look at the archosaurs, and are merely found in R. callenderi, saurischian dinosaurs, B. kupferzellensis, V. campi (elizabeth.grams., PEFO 33978), X. sapingensis (IVPP V6026), E. okeeffeae (AMNH FR 30587), and Hesperosuchus agilis (AMNH FR 6758; Langer & Benton, 2006 ; Nesbitt, 2011 ).
The morphology of center in order to posterior cervical spinal vertebrae is similar for the so much more prior cervical vertebrae compared to trunk area backbone when you look at the they’ve faint ventral keels and you may use up all your line of spine laminae; not, the newest centrum is far more equant in its proportions (Contour 8f). Also, this new diapophysis exists towards neural arc, the new zygapophyses try proportionally larger than much more anterior spinal vertebrae, the newest postzygapophyses run out of epipophyses, and also the transverse expansion of dorsal margin of the sensory lower back is most beneficial set-up. Hence, the brand new rear cervical vertebrae is actually transitional when you look at the morphology amongst the anterior cervical and middle-trunk area spinal vertebrae.
5.6.step 3 Trunk backbone
Persisted the latest trend observed in this new cervical collection, the original two trunk area spinal vertebrae (determined by the newest related rib type) are also transformation in morphology (Figure 8g) amongst the cervical spinal vertebrae together with trunk area backbone nearer to new sacrum. The new centra was anteroposteriorly more than dorsoventrally tall, together with centrum confronts try amphicoelous. The trunk centra use up all your ventral ridges to your midline (= ventral keels). This new prezygapophysis is created 29° off horizontal, whereas the bookofsex fresh new postzygapophysis are built merely 20° regarding lateral. The sensory spine is far more expanded anteroposteriorly compared to brand new cervical vertebrae; this expansion comes from really-developed dorsoventral laminae into anterior and you may rear sides of sensory back. Brand new dorsal part of the sensory back is actually extended laterally towards the a thorough “lower back dining table” which have a condo dorsal epidermis, similar to that of aetosaurs (age.g.,D. spurensis, MNA V9300). Into the dorsal evaluate, such back tables was center-shaped into top of one’s center pointing posteriorly. The diapophysis and you may parapophysis was linked because of the a proper-set-up paradiapophyseal lamina; that it lamina is found in other archosaurs (age.g., Nesbitt, 2005b ), however it is particularly highest within these spinal vertebrae regarding R. callenderi. The parapophysis is for the neural arc, but it is perhaps not dorsal to the dorsalmost extension of the centrum. The initial a couple trunk area spinal vertebrae enjoys meagerly create centroprezygapophyseal, centropostzygapophyseal, spinoprezygapophyseal, spinopostzygapophyseal, prezygodiapophyseal, postzygodiapophyseal, and you will intrapostzygapophyseal laminae distinguishing her or him on the cervical vertebrae (Wilson, 1999 ).
step 1.25pared for the first two trunk spinal vertebrae, this new parapophysis is a lot closer to the latest diapophysis; the newest parapophysis is just anteromedial towards the diapophysis and tend to be connected by a little paradiapophyseal lamina. The fresh centrozygapophyseal and you can spinozygapophyseal laminae commonly once the pronounced regarding much more posterior trunk spinal vertebrae, though the intrapostzygapophyseal lamina stays distinct, and you can a great intrina can be obtained. The newest sensory spines are cardio-designed like the transitional backbone, however they are some so much more anteroposteriorly elongate.
