6.dos.1 Diagnosing the fresh new Genus Revueltosaurus
The new holotypes out-of R. callenderi (NMMNH P-4957), “Revueltosaurus” hunti (NMMNH P-29357), and also the has just attributed species “Revueltosaurus” (= Pekinosaurus) olseni (YPM 7666; Heckert mais aussi al., 2012 ) per were just one isolated tooth which was the foundation getting its specific medical diagnosis. Lately, Heckert et al. ( 2012 ) detected the fresh new genus Revueltosaurus (comprising R. callenderi, Roentgen. hunti, and you may Roentgen. olseni) utilizing the following blend of character states: proportions (tooth crowns up to 7 in order to fifteen-mm high); numerous short denticles (over eight for every carina) that are counterbalance (sub-perpendicular) to your enamel margin; denticles proportionately small and sometimes worn towards the enamel by the accurate occlusion; not enough a real cingulum; premaxillary enamel crowns which might be everything two times as extreme because the maxillary/dentary tooth crowns and you can weakly recurved; and you may maxillary/dentary tooth crowns phyllodont (leaf-shaped). g., Ezcurra, 2016 ). Such, the mixture of one’s sized tooth, the amount of the fresh denticles, additionally the direction of the denticles convergence with other distantly related taxa (e.grams., Silesaurus opolensis, Dzik, 2003 ; Azendohsaurus madagaskarensis, Flynn et al., 2010 ). The type “denticles proportionately quick and regularly used toward enamel by the right occlusion” does not have accuracy when it comes to what’s considered “quick,” together with wear pattern is hard to eliminate in other taxa and you may relies on a certain ages of tooth when you look at the substitute for period (i.elizabeth., young pearly whites would not be diagnosable because there wouldn’t be worn). Furthermore, its lack of apomorphic character states (e.g., lack of cingulum) shouldn’t be used in a diagnosis, since they are symplesiomorphies. Additionally, the fresh new project of tooth reputation based on a single tooth (elizabeth.grams., premaxillary tooth crowns is actually everything doubly extreme due to the fact maxillary/dentary enamel crowns and weakly recurved; maxillary/dentary enamel crowns leaf designed) can not be determined from the completely new particular procedure, as well as with an increase of teeth on same area, simply craniodental topic with pearly whites offer the latest relationship out of tooth shape and tooth position. Hence, this new recommended enamel position of holotype pearly whites from K. hunti and you can P. olseni is believed based on an enthusiastic inferred intimate connection with Roentgen. callenderi, which is recognized of craniodental procedure with white teeth (get a hold of above). To summarize, new genus Revueltosaurus sensu lato can’t be adequately and sustainably detected in accordance with the form of materials away from R. callenderi, K. hunti, and P. olseni and then we hence maximum the fresh new genus to just one kinds, R. callenderi. As a result, we suggest that “R”. hunti take care of the subjective junior synonym Krzyzanowskisaurus hunti since the erected because of the Heckert ( 2005 ) and you may “R”. olseni take care of the subjective elder word Pekinosaurus olseni. I further alerting the assignment of every present isolated tooth taxa to Revueltosaurus.
We perform understand that later, with increased over question, R. callenderi, Krzyzanowskisaurus hunti, and you can Pekinosaurus olseni get show a good monophyletic genus Revueltosaurus, but a project of all the three variety to at least one genus is not already you’ll because it helps make an a priori presumption regarding the dating mennation kuponlarД± (discover lower than) that’s parallel for the unique argument that the Revueltosaurus pearly whites were assignable so you’re able to Ornithischia to begin with. This could has undesired flowing outcomes towards the subsequent macroevolutionary education (e.grams., biogeography and you will paleocology). As an alternative, it can be possible that these taxa may begin away getting distantly relevant.
six.2.2 What is Krzyzanowskisaurus hunti?
Heckert ( 2002 ) demonstrated “Revueltosaurus” hunti, after assigned to the genus Krzyzanowskisaurus (Heckert, 2005 ), centered on separated teeth throughout the Los Esteros Person in brand new Santa Rosa Development (Dockum Class) in the main The fresh Mexico and also the Blue Mesa Member of the fresh Chinle Creation during the eastern Washington (sort of locality from A beneficial. geoffreyi-look for ), features also been accepted in the straight down Chinle Creation into the southeastern Utah ( , p. 16). Krzyzanowskisaurus hunti pearly whites is actually celebrated off Roentgen. callenderi white teeth of the exposure out-of a ridge (“cingulum”) on the bottom of your enamel top, which connects into carinae and is commonly denticulated (Heckert, 2002 , 2005 ; Irmis, Parker, ainsi que al., 2007 ; Numbers 14a, b). To begin with, Krzyzanowskisaurus is called because of the different morphology of teeth ranging from the 2 versions additionally the conflict that the Krzyzanowskisaurus pearly whites nevertheless were assignable in order to an ornithischian unlike good pseudosuchian (Heckert, 2005 ). Irmis, Parker, ainsi que al. ( 2007 ) disagreed towards project from Krzyzanowskisaurus hunti for the Ornithischia dependent to the equivalent objections detailing the difficulties regarding assigning remote white teeth so you can ornithischians given that displayed in the past therefore the build that Heckert ( 2002 , 2005 ) identified as an excellent “cingulum” was not homologous with the exact same formations for the ornithischian dinosaurs. Additionally, Irmis, Parker, et al. ( 2007 ) as well as noted you to definitely an excellent Revueltosaurus-such squamosal, quadrate, and you can osteoderms were as well as available at an identical Arizona locality just like the Krzyzanowskisaurus hunti white teeth, exactly as got occurred from the particular area to possess R. callenderi (Seem ainsi que al., 2005 ).