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6.2 R. callenderi, Revueltosaurus-such as taxa, while the remote enamel situation

6.2 R. callenderi, Revueltosaurus-such as taxa, while the remote enamel situation

According to our very own study, Roentgen

The initial around three reputation states strengthen new articulations between the facial elements in the mouth musculature (Schumacher, 1973 ). The location of your own abducens will foramen is actually to start with hypothesized as the a possible synapomorphy supporting a beneficial crocodylomorph + aetosaur clade private of almost every other pseudosuchians (Gower, 2002 ), however, new phylogenetic analyses, in addition to ours, strongly recommend it apomorphy developed twice-once from inside the aetosauriforms and once inside crocodylomorphs. Yet not quantified in this study, a beneficial dorsoventrally thickened head rooftop (we.e., nasals, frontals, and you will parietals) is also mutual from the R. callenderi, erpetosuchids, and aetosaurs.

callenderi and you may aetosaurs express similarities on size of the fresh new hindlimb so you’re able to forelimb and form of brand new humerus and you may proximal ankle issue, in the event men and women parallels weren’t unambiguous synapomorphies. Particularly, R. callenderi and you will aetosaurs share a shortened radius in accordance with the humerus, and you can an excellent concave rear skin of one’s calcaneal tuber, even when these types of apomorphies has a very common shipment one of Archosauria. Roentgen. callenderi and you will aetosaurs express middle trunk spinal vertebrae which have diapophyses and you will parapophyses one develop laterally where both articulations originate on the good transverse process. Highest aetosaurs (age.grams., D. spurensis, MNA V9300; T. coccinarum, NMMNH P-12964; Parker, 2008 ; Heckert mais aussi al., 2010 ) develop these processes sideways and you can partly otherwise entirely coossify these to the brand new particular rib to form a general dorsal surface. The latest extension of your transverse techniques when you look at the Roentgen. callenderi or any other aetosaurs generally seems to associate for the exposure away from greater osteoderms. While doing so, but not quantified regarding phylogenetic study, R. callenderi and aetosaurs share a great hypertrophied last trochanter of your femur, a nature condition in past times believed book in order to aetosaurs (Short, 2002 ).

New similarities of osteoderms out-of R. callenderi, aetosaurs, and An excellent. geoffreyi offer more support for the the latest clade, Aetosauriformes, demonstrated right here. callenderi, An excellent. geoffreyi, and aetosaurs share the following carapacial synapomorphies (Shape 12): (a) the clear presence of horizontal osteoderms at least about trunk area (along with found in erpetosuchids); (b) a keen anterior bar found on the anterior side of the fresh new osteoderm (in addition to shared with Age. olseni and you can crocodylomorphs); (c) a great ventral carapace on the trunk area; and you can (d) presacral dorsal osteoderms that will be large than much time. Wrapped in an entire selection of paramedian, lateral, and you will ventral osteoderms, the newest osteoderm plans of R. callenderi and you will A beneficial. geoffreyi both resemble that aetosaurs ( ).

Postcranially, Roentgen

Clearly there can be still a huge morphological pit between the skeletal morphology from R. callenderi which away from aetosaurian members of Aetosauriformes considering the high service towards monophyly of all of the most other aetosaurs within this analysis and others (age.g., ). Following the divergence regarding Roentgen. callenderi + A beneficial. geoffreyi chat hour hesap silme and you can aetosaurs using their popular predecessor, brand new head, carapace, and you may postcranial bones of aetosaurs undergone after that evolutionary changes relative to most other diapsids. The brand new skulls regarding aetosaurs display improvement of your anterior portion of this new head of the elongating the premaxillae to make an anteroposteriorly increased exterior naris; the fresh supratemporal fenestra turned sideways founded, as well as in brand new mandible the prior dentition are reduced and you may became “slipper-shaped” (Desojo mais aussi al., 2013 ; Reyes mais aussi al., 2020 ). Brand new carapace off aetosaurs became alot more thorough, coating perhaps the ventral part of the tail (Heckert mais aussi al., 2010 ). The latest postcranial bones try further altered to pay towards hefty carapace having hypertrophied limb factors (just like ankylosaur dinosaurs) such as the strong humeri and tibiae in addition to a good pronounced olecranon procedure of the ulna. Which have a virtually identical armour carapace can it be no surprise these exact same facets during the Roentgen. callenderi have become equivalent inside their standard of robustness.

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