ull ; ▁absence ▁of ▁flo oring ▁of ▁the ▁cav um ▁ac ust ico - j ug ul are ; ▁process us ▁inter fen est ral is ▁of ▁the ▁op is th otic ▁more ▁sl ender ▁than ▁that ▁of ▁more ▁bas al ▁forms ▁but ▁more ▁robust ▁than ▁that ▁of ▁crown - group ▁t urt les ; ▁separate ▁open ings ▁of ▁the ▁can alis ▁ca vern os um ▁and ▁can alis ▁st aped io - tem por alis ▁present ▁within ▁the ▁cav um ▁ac ust ico - j ug ul are ; ▁a ▁reduced ▁thick ness ▁of ▁the ▁basic ran ium ▁floor ▁compar able ▁with ▁that ▁of ▁crown - group ▁t urt les ; ▁well - develop ed ▁an tr um ▁post otic um ; ▁flat ▁and ▁horizontal ▁vom er ▁that ▁is ▁free ▁of ▁contacts ▁for ▁most ▁of ▁its ▁length ▁except ▁at ▁its ▁extrem ities ▁and ▁along ▁a ▁short ▁s uture ▁with ▁the ▁pre front al ; ▁absence ▁of ▁process us ▁tro ch lear is ▁ot icum ; ▁poster ov entr ally ▁open ▁in cis ura ▁col um ella e ▁aur is ; ▁at ▁least ▁eight ▁neur als ▁( an ▁additional ▁plate ▁between ▁neural ▁ 8 ▁and ▁sup ra py gal ▁ 1 ▁may ▁be ▁a ▁nin th ▁neural ▁or ▁a ▁super numer ary ▁sup ra py gal ), ▁two ▁broad ▁sup ra py g als , ▁and ▁eight ▁cost als ▁present ; ▁absence ▁of ▁car apa cial ▁or ▁pl astr al ▁font an elle ▁in ▁adult ▁individuals ; ▁one ▁short ▁but ▁broad ▁cer v