6.2.step 1 Diagnosis the Genus Revueltosaurus
The brand new holotypes of R. callenderi (NMMNH P-4957), “Revueltosaurus” hunti (NMMNH P-29357), while the recently charged varieties “Revueltosaurus” (= Pekinosaurus) olseni (YPM 7666; Heckert ainsi que al., 2012 ) for every happened to be one separated tooth which was the cornerstone to own the certain analysis. Of late, Heckert ainsi que al. ( 2012 ) detected the fresh genus Revueltosaurus (spanning Roentgen. callenderi, R. hunti, and Roentgen. olseni) with the following blend of character says: proportions (enamel crowns as much as 7 in order to fifteen-mm extreme); multiple small denticles (more seven for every single carina) that are counterbalance (sub-perpendicular) toward tooth margin; denticles proportionately small and often used with the enamel by the precise occlusion; lack of a true cingulum; premaxillary enamel crowns that are whenever two times as tall as maxillary/dentary enamel crowns and weakly recurved; and you will maxillary/dentary tooth crowns phyllodont (leaf-shaped). g., Ezcurra, 2016 ). Such as for example, the blend of your measurements of one’s teeth, just how many brand new denticles, together with orientation of the denticles overlap along with other distantly related taxa (elizabeth.g., Silesaurus opolensis, Dzik, 2003 ; Azendohsaurus madagaskarensis, Flynn ainsi que al., 2010 ). The character “denticles proportionately short and sometimes used towards enamel because of the right occlusion” lacks reliability with respect to what’s experienced “brief,” together with wear trend is difficult to help you exclude in other taxa and relies on a certain age of tooth when you look at the replacement stage (we.age., more youthful pearly whites wouldn’t be diagnosable because there wouldn’t be worn). In addition, the absence of apomorphic profile claims (age.g., absence of cingulum) shouldn’t be included in an analysis, as they are symplesiomorphies. At exactly the same time, the latest task away from enamel updates centered on one tooth (age.g., premaxillary enamel crowns is whenever two times as tall because maxillary/dentary tooth crowns and weakly recurved; maxillary/dentary enamel crowns leaf molded) can not be calculated on the fresh types of situation, and even with more pearly whites regarding the same locality, simply craniodental matter which have teeth provide the brand new association of tooth shape and enamel updates. For this reason, the new suggested enamel status of the holotype teeth regarding K. hunti and you will P. olseni is believed according to an enthusiastic inferred romantic connection with R. callenderi, that is recognized from craniodental question that have white teeth (pick significantly more than). To conclude, new genus Revueltosaurus sensu lato cannot be acceptably and sustainably identified according to research by the sort of information away from Roentgen. callenderi, K. hunti, and P. olseni therefore we ergo limitation the newest genus to one varieties, R. callenderi. As such, we suggest that “R”. hunti keep up with the personal junior synonym Krzyzanowskisaurus hunti given that erected by the Heckert ( 2005 ) and you can “R”. olseni maintain the subjective older synonym Pekinosaurus olseni. I next warning the new assignment of any existing separated tooth taxa so you’re able to Revueltosaurus.
I do realize that subsequently, with additional complete procedure, Roentgen. callenderi, Krzyzanowskisaurus hunti, and you will Pekinosaurus olseni get portray a great monophyletic genus Revueltosaurus, however, an assignment of all three variety to just one genus isn’t currently you’ll be able to whilst helps make an a priori expectation regarding the matchmaking (come across lower than) that is parallel for the modern argument your Revueltosaurus pearly whites have been assignable so you’re able to Ornithischia to begin with. This could has unwanted cascading outcomes into the further macroevolutionary studies (age.g., biogeography and you will paleocology). Rather, it’s very possible these taxa may begin away as distantly related.
six.dos.2 What exactly is Krzyzanowskisaurus hunti?
Heckert ( 2002 ) demonstrated “Revueltosaurus” hunti, after allotted to brand new genus Krzyzanowskisaurus (Heckert, 2005 ), considering separated white teeth from the Los Esteros Member of brand new Santa Rosa Creation (Dockum Group) into the central Brand new Mexico and also the Bluish Mesa Person in this new Chinle Formation from inside the eastern Washington (particular locality away from A great. geoffreyi-get a hold of ), features also been recognized throughout the all the way down Chinle Development inside the southeastern Utah ( , p. 16). Krzyzanowskisaurus hunti pearly whites is distinguished of R. callenderi white teeth by the exposure off an excellent ridge (“cingulum”) on the bottom of your own tooth crown, and that connects toward carinae that’s have a tendency to denticulated (Heckert, 2002 , 2005 ; Irmis, Parker, ainsi que al., 2007 ; Numbers 14a anastasiadate ekЕџi, b). To start with, Krzyzanowskisaurus are named given the disparate morphology of your own white teeth ranging from both versions and the conflict that the Krzyzanowskisaurus teeth nevertheless were assignable to an enthusiastic ornithischian in place of an effective pseudosuchian (Heckert, 2005 ). Irmis, Parker, ainsi que al. ( 2007 ) disagreed into the task out of Krzyzanowskisaurus hunti into Ornithischia mainly based towards equivalent objections describing the issues from assigning isolated white teeth to help you ornithischians as exhibited in earlier times therefore the design that Heckert ( 2002 , 2005 ) defined as an excellent “cingulum” was not homologous with similar formations during the ornithischian dinosaurs. Also, Irmis, Parker, et al. ( 2007 ) in addition to listed that a good Revueltosaurus-including squamosal, quadrate, and you will osteoderms were plus available at the same Washington area once the Krzyzanowskisaurus hunti pearly whites, just as got took place at the type locality to own Roentgen. callenderi (Hunt et al., 2005 ).