8 7 ▁Category : 1 9 8 7 ▁establish ments ▁in ▁New ▁Zealand <0x0A> </s> ▁D ana oc eras ▁is ▁a ▁na util oid ▁ce phal op od ▁from ▁the ▁middle ▁Sil ur ian ▁of ▁central ▁Europe ▁included ▁in ▁the ▁on c oc ero id ▁family ▁Poly el asm oc er at idae . ▁Similar ▁spec im ens ▁from ▁the ▁middle ▁Dev onian ▁of ▁North ▁America ▁may ▁belong . ▁ ▁D ana oc eras ▁has ▁a ▁later ally ▁com pressed ▁shell ▁cur ved ▁such ▁that ▁the ▁vent ral ▁or ▁si ph unc ular ▁side ▁is ▁longitud in ally ▁con ca ve , ▁i . e . ▁is ▁end og ras tr ic . ▁The ▁si ph un cle , ▁which ▁is ▁vent r ally ▁subm arg inal , ▁contains ▁l amin ar ▁act in osi phon ate ▁depos its . ▁ ▁D ana oc eras ▁is ▁the ▁ancest ral ▁genus ▁of ▁the ▁Poly el asm oc er at idae ▁and ▁is ▁possibly ▁derived ▁from ▁either ▁O on oc eras ▁or ▁O oc er ina ▁of ▁the ▁On c oc er at idae ▁based ▁on ▁similar ities ▁of ▁the ▁si ph un cle ▁ ▁References ▁▁ ▁Walter ▁C . ▁S weet , ▁ 1 9 6 4 . ▁N aut ilo idea ▁- ▁On c oc er ida ; ▁Tre at ise ▁on ▁In verte br ate ▁Pale ont ology , ▁Part ▁K . ▁Ge ological ▁Society ▁of ▁America . ▁ ▁Category : Pre histor ic ▁na util oid ▁gener a <0x0A> </s> ▁Lith