Several other wider-level research out-of archosaur dating because of the Nesbitt et al


None Parker ainsi que al. ( 2005 ) nor Check et al. ( 2005 ) attempted a great phylogenetic study off R. callenderi according to research by the the new skeletal procedure. However, one another communities detailed several popular features of this new hindlimb that have been unambiguous synapomorphies away from Pseudosuchia. Parker et al. ( 2005 ) hypothesized a possible aunt-category reference to aetosaurs, noting new morphological parallels of one’s squamosal and you may paramedian osteoderms. An identical position try suggested because of the Check mais aussi al. ( 2005 ) based on unspecified profile states of the tarsus in addition to osteoderms. Brusatte et al. ( 2010 ) integrated Roentgen. callenderi in their studies out-of very early archosaur matchmaking, programming on typed data and descriptions regarding Parker et al. ( 2005 ) and you can Search ainsi que al. ( 2005 ). You to studies retrieved Roentgen. callenderi due to the fact sis taxon for the very early-diverging suchian clade Ornithosuchidae. ( 2011 ) recovered Roentgen. callenderi during the a proper-offered updates because sibling taxon so you can aetosaurs, an outcome backed by newer studies (e.g., Butler et al., 2014 ; ; Nesbitt & Butler, 2013 ; Nesbitt ainsi que al., 2014 ; Nesbitt mais aussi al., 2020 ; Nesbitt, Stocker, ainsi que al., 2018 ).

It sum totally identifies brand new osteology of Roentgen. callenderi according to no less than a dozen someone (predicated on femora amount) off PEFO along with three well-maintained relevant partial skeletons compiled between 2005 and you will 2015, brings osteohistological framework, and talks about new taxon’s characteristics for insights very early suchian development.

dos.1 Stratigraphic status

This malfunction off R. callenderi was mainly according to thing out of numerous localities regarding the Chinle Development off Petrified Tree Federal Playground (PEFO), Arizona, You (Shape step 1; discover Medical Paleontology). The top Triassic Chinle Formation in this region comprises mainly fluvial and floodplain strata out of alternating claystones, siltstones, sandstones, and you may conglomerates (Billingsley, 1985 ; Heckert & Lucas, 2002a ; ). The latest Chinle Creation in the Petrified Forest National Playground town preserves well-known fossil assemblages from flowers (palynomorphs, actually leaves, wood), invertebrates, and you will vertebrates (age.g., Ash, 2005 ; Baranyi ainsi que al., 2018 ; A beneficial, 1998 ; Irmis, 2005 ; Litwin, Traverse, & Ash, 1991 ; Parker, 2005b , 2006 ; Reichgelt et al., 2013 ). Really non-dentigerous and low-osteoderm specimens off Roentgen. callenderi of PEFO, and men and women explained right here, have been found quickly more than Coated Wasteland Sandstone step three (sensu Billingsley, 1985 ; Lithodendron Wash Sleep sensu Heckert & Lucas, 2002a ) among the main Petrified Tree Associate (sensu Woody, 2006 ) of upper area of the Chinle Formation (Heckert & Lucas, 2002a ; Irmis, 2005 ; Padian, 1990 ; Parker, 2005b , 2006 ; Parker ainsi que al., 2005 ; Parker & ). Separated teeth regarding Roentgen. callenderi had been recovered from microvertebrate assemblages away from low in the fresh Chinle Formation at the PEFO, stretching the fresh stratigraphic range of this taxon with the Sonsela Member and you may uppermost Bluish Mesa Associate (get a hold of Medical Paleontology).

The three head localities one brought brand new specimens regarding Roentgen. callenderi explained here (Studies S1) are definitely the Revueltosaurus Quarry (PFV 297), Revueltosaurus Quarry SW (PFV 414), and also the Providing Website (PFV 231). The internet sites exists given that paleosols during the a piled fluvial succession inside the the midst of the newest Petrified Tree Affiliate (Atchley mais aussi al., 2013 ; Loughney mais aussi al., 2011 ; Parker ainsi que al., 2005 ; Parker & ). PFV 297 and PFV 414 is actually broke up spatially by the 20 meters and are also subsequently regarding the two hundred meters into the the southern area of off PFV 231 (Shape 1a). Decorated Wasteland Sandstone step three, and this immediately underlies every about three localities, are stratigraphically


40–fifty meters over the root of the Petrified Tree Associate (Profile 1b; Parker & ), and you may is short for a piece sandstone transferred of the perennial circulate in good high sinuosity river channel (Johns, 1988 ). PFV 297 and you may PFV 414 occur somewhat highest in the sequence than just PFV 231 (Parker & ).