6.2 Roentgen. callenderi, Revueltosaurus-for example taxa, and also the separated enamel condition
According to our research, R
The first around three profile claims reinforce the articulations involving the face facets from the mouth musculature (Schumacher, 1973 ). The region of your abducens bravery foramen is actually originally hypothesized since the a possible synapomorphy help a crocodylomorph + aetosaur clade personal regarding other pseudosuchians (Gower, 2002 ), but newer phylogenetic analyses, along with ours, suggest this apomorphy advanced at least twice-just after inside aetosauriforms as soon as into the crocodylomorphs. But not quantified within this analysis, a great dorsoventrally thickened head rooftop (we.e., nasals, frontals, and you can parietals) is also common of the R. callenderi, erpetosuchids, and aetosaurs.
callenderi and you can aetosaurs share parallels throughout the dimensions of the latest hindlimb to help you forelimb and you can shape of the newest humerus and you may proximal foot factors, regardless if men and women parallels weren’t unambiguous synapomorphies. Specifically, R. callenderi and you can aetosaurs share a shortened distance in accordance with this new humerus, and you may a concave rear epidermis of calcaneal tuber, even when these apomorphies has a prevalent distribution one of Archosauria. Roentgen. callenderi and you can aetosaurs show middle trunk area vertebrae which have diapophyses and you may parapophyses that grow sideways where one another articulations originate on the an excellent transverse techniques. High aetosaurs (age.g., D. spurensis, MNA V9300; T. coccinarum, NMMNH P-12964; Parker, 2008 ; Heckert mais aussi al., 2010 ) build these methods sideways and partially or entirely coossify them to the fresh particular rib to create a broad dorsal surface. The latest expansion of transverse processes in the R. callenderi or other aetosaurs seems to correlate on presence out of broad osteoderms. As well, however quantified on phylogenetic analysis, R. callenderi and you can aetosaurs display a good hypertrophied 4th trochanter of the femur, a character state in the past thought unique to aetosaurs (Brief, 2002 ).
Brand new parallels of your own osteoderms out-of Roentgen. callenderi, aetosaurs, and you may A. geoffreyi bring most assistance for the the brand new clade, Aetosauriformes, exhibited here. callenderi, A beneficial. geoffreyi, and aetosaurs display the next carapacial synapomorphies (Figure 12): (a) the current presence of horizontal osteoderms at the least in the trunk region (as well as contained in erpetosuchids); (b) an prior club found on the prior edge of brand https://datingranking.net/tr/christiandatingforfree-inceleme/ new osteoderm (also shared with Elizabeth. olseni and you may crocodylomorphs); (c) a great ventral carapace in the trunk area; and you can (d) presacral dorsal osteoderms that are broad than much time. Wrapped in an entire number of paramedian, lateral, and you will ventral osteoderms, the brand new osteoderm arrangements of R. callenderi and you will A. geoffreyi one another resemble that aetosaurs ( ).
Postcranially, R
Obviously there is nevertheless a giant morphological pit between your skeletal morphology away from Roentgen. callenderi and this from aetosaurian people in Aetosauriformes because of the high support with the monophyly of the many almost every other aetosaurs within this research although some (elizabeth.g., ). Following divergence from R. callenderi + A beneficial. geoffreyi and you may aetosaurs off their well-known predecessor, the head, carapace, and you may postcranial skeleton off aetosaurs underwent then evolutionary changes according to almost every other diapsids. The new skulls regarding aetosaurs exhibit changes of your own prior percentage of the fresh new head from the elongating this new premaxillae to create an enthusiastic anteroposteriorly increased exterior naris; the supratemporal fenestra turned laterally situated, plus the latest mandible the latest anterior dentition try reduced and you may turned into “slipper-shaped” (Desojo et al., 2013 ; Reyes et al., 2020 ). The latest carapace of aetosaurs became a whole lot more comprehensive, coating possibly the ventral portion of the tail (Heckert mais aussi al., 2010 ). The fresh postcranial bones is next altered to compensate with the big carapace having hypertrophied limb issues (similar to ankylosaur dinosaurs) like the powerful humeri and tibiae along with a great obvious olecranon procedure for the fresh new ulna. Having an around identical armour carapace can it be no wonder this type of same issues inside R. callenderi are particularly similar inside their level of robustness.
