ation , ▁not ▁sc av eng ing , ▁given ▁its ▁size ▁relation ▁to ▁the ▁pre y , ▁as ▁s ph ages aur ids ▁were ▁usually ▁much ▁smaller ▁than ▁about ▁one ▁fourth ▁of ▁derived ▁b aur us uch ids . ▁▁ ▁A pl est os uch us ▁is ▁distinguished ▁form ▁all ▁other ▁known ▁Cro c ody l iformes ▁by ▁a ▁unique ▁combination ▁of ▁trait , ▁including ▁four ▁aut ap omorph ies . ▁It ▁poss esses ▁an ▁aut ap omorphic ▁nas al ▁b one ▁with ▁d ors al ▁mid line ▁cr est , ▁and ▁an ▁aut ap omorphic ▁front al ▁longitud inal ▁r idge ▁that ▁reaches ▁the ▁mid line ▁contact ▁between ▁the ▁pre front als . ▁Its ▁med ial ▁su pr at empor al ▁rim ▁is ▁cr est - sh aped , ▁and ▁the ▁r idge ▁along ▁the ▁e ct opter y go id - j ug al ▁s uture ▁is ▁not ched ▁at ▁its ▁ca ud al ▁portion . ▁A ▁later al ▁de pression ▁is ▁present ▁on ▁the ▁quadr ate ▁b one . ▁The ▁pal at ine ▁bar ▁is ▁aut ap omorph ically ▁cr ested ▁on ▁its ▁vent ral ▁surface , ▁and ▁cyl ind rical ▁in ▁its ▁d ors al ▁portion . ▁The ▁cho anal ▁sept um ▁is ▁also ▁rid ged ▁on ▁the ▁vent ral ▁surface . ▁An ▁aut ap omorphic ▁single ▁par ach o anal ▁f ossa ▁ro st rol ater al ▁to ▁the ▁par ach o anal ▁fen estra e ▁is ▁present ▁at ▁the ▁base ▁of ▁the ▁p tery go id ▁wing