▁This ▁brought ▁Od ont og ri ph us ▁into ▁the ▁center ▁of ▁a ▁debate ▁that ▁had ▁been ▁going ▁on ▁since ▁ 1 9 9 0 , ▁when ▁But ter field ▁denied ▁that ▁W iw ax ia ▁was ▁a ▁for er un ner ▁of ▁m oll us cs ▁and ▁argued ▁that ▁it ▁was ▁an ▁evolution ary ▁" a unt " ▁of ▁ann el ids . ▁In ▁particular ▁he ▁had ▁argued ▁that : ▁W iw ax ia ’ s ▁s cler ites ▁were ▁internally ▁much ▁more ▁like ▁the ▁br ist les ▁of ▁pol ych a ete ▁ann el ids ▁such ▁as ▁Canad ia ▁than ▁like ▁any ▁for er un ner ▁of ▁m oll us can ▁shell ▁pl ates ; ▁and ▁in ▁his ▁opinion ▁W iw ax ia ’ s ▁feed ing ▁appar atus ▁was ▁more ▁similar ▁to ▁that ▁of ▁some ▁pol ych a etes ▁than ▁to ▁a ▁m oll us can ▁rad ula . ▁Car on , ▁Sch el tem a , ▁et ▁al . ▁( 2 0 0 6 ) ▁thought ▁W iw ax ia ▁bore ▁little ▁res embl ance ▁to ▁pol ych a etes ▁as ▁it ▁showed ▁no ▁signs ▁of ▁segment ation , ▁append ages ▁in ▁front ▁of ▁the ▁mouth , ▁or ▁" leg s " ▁– ▁all ▁of ▁which ▁are ▁typical ▁pol ych a ete ▁features . ▁ ▁A ▁few ▁months ▁later ▁in ▁ 2 0 0 6 ▁But ter field ▁returned ▁to ▁the ▁f ray . ▁As ▁in ▁ 1 9 9 0 , ▁he ▁argued ▁that ▁W iw ax ia