2 0 1 5 , ▁the ▁bi olog ists ▁Juan ▁C . ▁Gar cia - R . ▁and ▁Steve ▁A . ▁T rew ick ▁anal ys ed ▁the ▁DNA ▁of ▁the ▁pur ple ▁sw am ph ens . ▁They ▁found ▁that ▁the ▁Lord ▁How e ▁sw am phen ▁was ▁most ▁closely ▁related ▁to ▁the ▁Philipp ine ▁sw am phen ▁( P . ▁pul ver ul ent us ), ▁and ▁the ▁black - back ed ▁sw am phen ▁( P . ▁indic us ) ▁more ▁closely ▁related ▁to ▁both ▁than ▁to ▁other ▁species ▁in ▁its ▁region . ▁Gar cia - R . ▁and ▁T rew ick ▁used ▁DNA ▁from ▁the ▁Vienna ▁spec imen , ▁but ▁were ▁unable ▁to ▁obtain ▁us able ▁DNA ▁from ▁the ▁Liverpool ▁spec imen . ▁They ▁suggested ▁that ▁the ▁Lord ▁How e ▁sw am phen ▁may ▁have ▁desc ended ▁from ▁a ▁few ▁migr ant ▁Philipp ine ▁sw am ph ens ▁during ▁the ▁late ▁Ple ist oc ene ▁( about ▁ 5 0 0 . 0 0 0 ▁years ▁ago ), ▁dispers ing ▁over ▁other ▁islands . ▁This ▁indicates ▁a ▁complex ▁history , ▁since ▁their ▁line ages ▁are ▁not ▁recorded ▁on ▁the ▁islands ▁between ▁them ; ▁according ▁to ▁the ▁bi olog ists , ▁such ▁results ▁( based ▁on ▁ancient ▁DNA ▁sources ) ▁should ▁be ▁treated ▁with ▁ca ution . ▁Although ▁many ▁pur ple ▁sw am phen ▁tax a ▁had ▁been ▁considered ▁sub species ▁of ▁the ▁species ▁P . ▁por phy rio , ▁they ▁considered ▁this ▁a ▁par ap hy let ic ▁(