. ▁ ▁The ▁ext ant ▁species ▁are ▁closely ▁related ▁and ▁thought ▁to ▁be ▁descend ants ▁of ▁birds ▁that ▁surv ived ▁a ▁gen etic ▁bott l ene ck ▁caused ▁by ▁the ▁marine ▁trans gression ▁during ▁the ▁O lig oc ene , ▁when ▁most ▁of ▁New ▁Zealand ▁was ▁under ▁water . ▁The ▁earliest ▁known ▁foss il ▁is ▁K ui orn is ▁indicator ▁from ▁the ▁Mi oc ene ▁Saint ▁Bath ans ▁Fa una . ▁K ui orn is ▁is ▁thought ▁to ▁be ▁more ▁closely ▁related ▁to ▁A can this it ta ▁than ▁to ▁other ▁A can this itt ids ▁▁ ▁The ▁relationships ▁between ▁the ▁gener a ▁and ▁species ▁were ▁formerly ▁poor ly ▁understood . ▁The ▁ext ant ▁genus ▁A can this it ta ▁has ▁one ▁species , ▁the ▁rif le man ▁and ▁the ▁other ▁surv iving ▁genus , ▁X en icus , ▁includes ▁the ▁New ▁Zealand ▁rock ▁w ren ▁and ▁the ▁recently ▁ext inct ▁bush w ren . ▁Some ▁authorities ▁have ▁retained ▁Ly all ' s ▁w ren ▁in ▁X en icus ▁as ▁well , ▁but ▁it ▁is ▁often ▁afford ed ▁its ▁own ▁monot yp ic ▁genus , ▁Tra vers ia . ▁The ▁st out - leg ged ▁w ren ▁( gen us ▁P ach y pl ich as ) ▁was ▁originally ▁split ▁into ▁two ▁species , ▁but ▁more ▁recent ▁research ▁disput es ▁this . ▁The ▁final ▁genus ▁was ▁D end ro sc ans or , ▁which ▁had ▁one ▁species , ▁the ▁long - bil led ▁w ren . ▁A ▁M ito ch ond rial ▁DNA