According to our investigation, Roentgen
The initial three character states reinforce this new articulations between your face elements of mouth musculature (Schumacher, 1973 ). The location of your abducens nerve foramen is actually to start with hypothesized since the a prospective synapomorphy supporting a great crocodylomorph + aetosaur clade personal away from most other pseudosuchians (Gower, 2002 ), however, more recent phylogenetic analyses, and ours, recommend that it apomorphy evolved twice-immediately following during the aetosauriforms as soon as from inside the crocodylomorphs. not quantified contained in this data, good dorsoventrally thickened skull roof (i.age., nasals, frontals, and you will parietals) is additionally shared by the Roentgen. callenderi, erpetosuchids, and you may aetosaurs.
callenderi and you may aetosaurs express similarities from the size of the new hindlimb so you can forelimb and you will form of the fresh humerus and you can proximal foot elements, whether or not people parallels were not unambiguous synapomorphies. Especially, Roentgen. callenderi and you will aetosaurs share a shortened distance according to the humerus, and good concave rear skin of one's calcaneal tuber, regardless if these types of apomorphies features a common shipping one of Archosauria. Roentgen. callenderi and aetosaurs display center trunk area spinal vertebrae with diapophyses and you may parapophyses you to develop sideways in which one another articulations originate on the good transverse process. Large aetosaurs (elizabeth.g., D. spurensis, MNA V9300; T. coccinarum, NMMNH P-12964; Parker, 2008 ; Heckert ainsi que al., 2010 ) expand these procedures laterally and you will partially or entirely coossify these to the latest particular rib to create a broad dorsal body. This new expansion of one's transverse procedure in Roentgen. callenderi or other aetosaurs seems to correlate into presence of greater osteoderms. In addition, but not quantified throughout the phylogenetic investigation, Roentgen. callenderi and you can aetosaurs show an excellent hypertrophied 4th trochanter of your femur, a nature state before sensed novel in order to aetosaurs (Short, 2002 ).
The latest parallels of the osteoderms of Roentgen. callenderi, aetosaurs, and you will A. geoffreyi promote most support for the this new clade, Aetosauriformes, demonstrated right here. callenderi, A good. geoffreyi, and aetosaurs display the second carapacial synapomorphies (Shape a dozen): (a) the presence of horizontal osteoderms at the least from the trunk region (and additionally present in erpetosuchids); (b) a keen anterior bar located on the prior edge of the new osteoderm (including distributed to Elizabeth. olseni and you may crocodylomorphs); (c) a beneficial ventral carapace from the trunk; and (d) presacral dorsal osteoderms which might be broad than a lot of time. Wrapped in a full set of paramedian, horizontal, and ashley madison promo kodlarД± you will ventral osteoderms, the new osteoderm agreements regarding Roentgen. callenderi and you may A great. geoffreyi each other resemble compared to aetosaurs ( ).
Demonstrably discover nevertheless a huge morphological pit involving the skeletal morphology regarding R. callenderi hence from aetosaurian members of Aetosauriformes given the large service on monophyly of all of the most other aetosaurs within analysis although some (e.grams., ). Pursuing the divergence regarding Roentgen. callenderi + An effective. geoffreyi and you will aetosaurs from their popular predecessor, the new head, carapace, and you may postcranial bones away from aetosaurs underwent next evolutionary transformations relative to other diapsids. The fresh skulls off aetosaurs display modifications of one's prior portion of brand new head by the elongating the new premaxillae in order to create a keen anteroposteriorly increased outside naris; the newest supratemporal fenestra turned into sideways dependent, plus the new mandible the latest anterior dentition is smaller and you will turned “slipper-shaped” (Desojo ainsi que al., 2013 ; Reyes mais aussi al., 2020 ). The fresh carapace from aetosaurs turned into so much more comprehensive, level even the ventral portion of the tail (Heckert mais aussi al., 2010 ). The brand new postcranial bones is actually subsequent altered to pay to your heavier carapace having hypertrophied limb points (just like ankylosaur dinosaurs) including the robust humeri and tibiae and a great noticable olecranon procedure for the fresh ulna. That have a very nearly identical armor carapace could it be no surprise this type of same facets when you look at the R. callenderi are particularly equivalent inside their degree of robustness.