six.2.step 1 Diagnosing new Genus Revueltosaurus
The holotypes away from R. callenderi (NMMNH P-4957), “Revueltosaurus” hunti (NMMNH P-29357), in addition to recently charged varieties “Revueltosaurus” (= Pekinosaurus) olseni (YPM 7666; Heckert et al., 2012 ) for each and every happened to be an individual isolated tooth which had been the cornerstone getting its specific diagnosis. Most recently, Heckert et al. ( 2012 ) detected the new genus Revueltosaurus (comprising R. callenderi, Roentgen. hunti, and Roentgen. olseni) utilizing the after the mix of profile says: proportions (enamel crowns just as much as 7 to help you 15-mm high); multiple small denticles (more seven for each carina) which might be counterbalance (sub-perpendicular) into the tooth margin; denticles proportionately brief and sometimes used on the tooth from the perfect occlusion; insufficient a real cingulum; premaxillary enamel crowns that will be as much as doubly tall because the maxillary/dentary enamel crowns and weakly recurved; and you will maxillary/dentary tooth crowns phyllodont (leaf-shaped). g., Ezcurra, 2016 ). Including, the mixture of your own size of tooth, exactly how many the latest denticles, together with positioning of denticles overlap with other distantly associated taxa (e.g., Silesaurus opolensis, Dzik, 2003 ; Azendohsaurus madagaskarensis, Flynn ainsi que al., 2010 ). The type “denticles proportionately quick and often used towards tooth of the exact occlusion” lacks accuracy with regards to what’s noticed “brief,” and also the wear pattern is hard so you can exclude various other taxa and you will depends on a particular ages of tooth inside replacement for stage (we.elizabeth., datingranking.net/tr/latinamericancupid-inceleme/ young pearly whites would not be diagnosable as there would not be worn). Furthermore, the absence of apomorphic profile says (elizabeth.grams., lack of cingulum) really should not be utilized in a diagnosis, because they are symplesiomorphies. On the other hand, new task off tooth updates considering a single tooth (e.g., premaxillary enamel crowns try whenever two times as extreme since maxillary/dentary enamel crowns and weakly recurved; maxillary/dentary enamel crowns leaf formed) can’t be computed in the fresh type matter, and even with more white teeth regarding same locality, just craniodental material having teeth also provide the new connection regarding tooth contour and you can tooth position. Therefore, the brand new suggested enamel position of holotype white teeth off K. hunti and you may P. olseni is thought predicated on a keen inferred intimate connection with Roentgen. callenderi, that is understood off craniodental material that have pearly whites (see over). In conclusion, the brand new genus Revueltosaurus sensu lato can not be effectively and you will sustainably diagnosed based on the style of product out-of R. callenderi, K. hunti, and P. olseni therefore ergo limitation the fresh genus to a single types, Roentgen. callenderi. As a result, i suggest that “R”. hunti keep up with the personal junior word Krzyzanowskisaurus hunti as erected because of the Heckert ( 2005 ) and you will “R”. olseni maintain the subjective senior word Pekinosaurus olseni. We further caution this new project of any present separated tooth taxa in order to Revueltosaurus.
I create keep in mind that subsequently, with more complete question, R. callenderi, Krzyzanowskisaurus hunti, and you can Pekinosaurus olseni get represent a beneficial monophyletic genus Revueltosaurus, but a project of all around three variety to a single genus is not currently you’ll be able to as it renders a the priori assumption about relationship (get a hold of less than) that is parallel into the brand-new argument the Revueltosaurus teeth were assignable in order to Ornithischia first off. This may keeps unwelcome streaming consequences into the further macroevolutionary education (age.grams., biogeography and you may paleocology). Alternatively, it is reasonably possible these taxa may begin away are distantly associated.
6.dos.dos What is actually Krzyzanowskisaurus hunti?
Heckert ( 2002 ) revealed “Revueltosaurus” hunti, afterwards allotted to the new genus Krzyzanowskisaurus (Heckert, 2005 ), centered on isolated pearly whites on Los Esteros Member of the newest Santa Rosa Formation (Dockum Category) in the central New Mexico and Bluish Mesa Member of the Chinle Creation into the eastern Washington (types of area regarding A great. geoffreyi-come across ), and contains been already recognized regarding straight down Chinle Creation within the southeastern Utah ( , p. 16). Krzyzanowskisaurus hunti teeth are well-known from R. callenderi white teeth because of the visibility out of good ridge (“cingulum”) toward the base of one’s tooth crown, which connects to the carinae and that is often denticulated (Heckert, 2002 , 2005 ; Irmis, Parker, et al., 2007 ; Figures 14a, b). To begin with, Krzyzanowskisaurus was called considering the different morphology of white teeth between the 2 variations plus the dispute the Krzyzanowskisaurus pearly whites nonetheless was basically assignable so you’re able to an ornithischian instead of a pseudosuchian (Heckert, 2005 ). Irmis, Parker, mais aussi al. ( 2007 ) disagreed towards the project out-of Krzyzanowskisaurus hunti towards Ornithischia founded towards the comparable objections outlining the problems away from assigning isolated pearly whites so you’re able to ornithischians once the shown in the past and design that Heckert ( 2002 , 2005 ) identified as a good “cingulum” wasn’t homologous with the same structures inside ornithischian dinosaurs. Furthermore, Irmis, Parker, ainsi que al. ( 2007 ) as well as detailed that good Revueltosaurus-such squamosal, quadrate, and you may osteoderms was indeed together with available at an equivalent Washington locality as the Krzyzanowskisaurus hunti pearly whites, exactly as got happened on variety of area to own Roentgen. callenderi (Take a look ainsi que al., 2005 ).