N ▁( which ▁gover ns ▁the ▁scientific ▁names ▁of ▁animals ), ▁the ▁name ▁A pat osa urus , ▁having ▁been ▁published ▁first , ▁has ▁priority ▁as ▁the ▁official ▁name ; ▁Br ont osa urus ▁was ▁considered ▁a ▁junior ▁syn onym ▁and ▁was ▁therefore ▁long ▁disc arded ▁from ▁formal ▁use . ▁Despite ▁this , ▁at ▁least ▁one ▁pale ont ologist Ro bert ▁T . ▁Bak ker arg ued ▁in ▁the ▁ 1 9 9 0 s ▁that ▁A . ajax ▁and ▁A . ex c els us ▁were ▁in ▁fact ▁sufficiently ▁distinct ▁for ▁the ▁latter ▁to ▁mer it ▁a ▁separate ▁genus . ▁ ▁In ▁ 2 0 1 5 ▁E manuel ▁Tsch opp , ▁Oct áv io ▁Mate us , ▁and ▁Roger ▁B enson ▁released ▁a ▁paper ▁on ▁di pl od oc oid ▁system at ics , ▁and ▁proposed ▁that ▁gener a ▁could ▁be ▁diagn osed ▁by ▁th ir teen ▁differ ing ▁characters , ▁and ▁species ▁separated ▁based ▁on ▁six . ▁The ▁minimum ▁number ▁for ▁generic ▁separation ▁was ▁chosen ▁based ▁on ▁the ▁fact ▁that ▁A . ajax ▁and ▁A . lou is ae ▁differ ▁in ▁twelve ▁characters , ▁and ▁Di pl od ocus ▁car neg iei ▁and ▁D . hall orum ▁differ ▁in ▁eleven ▁characters . ▁Thus , ▁th ir teen ▁characters ▁were ▁chosen ▁to ▁validate ▁the ▁separation ▁of ▁gener a . ▁The ▁six ▁differ ing ▁features ▁for ▁specific ▁separation ▁were ▁chosen ▁by ▁counting ▁the ▁number ▁of ▁differ ing ▁features ▁in ▁separate ▁spec im ens ▁generally ▁agreed ▁to ▁represent ▁one ▁species , ▁with ▁only