▁O ax aca ▁in ▁southern ▁Mexico , ▁Th re aten ed ▁by ▁def or est ation ▁and ▁water ▁poll ution , ▁it ▁is ▁listed ▁as ▁End anger ed ▁by ▁the ▁International ▁Union ▁for ▁Conserv ation ▁of ▁Nature ▁( I U CN ). ▁ ▁Tax onomy ▁The ▁Mexican ▁water ▁mouse ▁was ▁first ▁described ▁as ▁R he om ys ▁mex ican us ▁in ▁ 1 9 5 9 ▁by ▁the ▁American ▁zo ologist ▁George ▁Gilbert ▁Good win . ▁He ▁was ▁the ▁assistant ▁cur ator ▁of ▁m amm als ▁at ▁the ▁American ▁Museum ▁of ▁Natural ▁History ▁in ▁New ▁York ▁City , ▁and ▁went ▁on ▁a ▁number ▁of ▁collect ing ▁exped itions , ▁including ▁one ▁to ▁Iran ▁in ▁ 1 9 3 8 . ▁ ▁Distribution ▁The ▁species ▁is ▁en demic ▁to ▁Mexico ▁and ▁has ▁a ▁very ▁restricted ▁range ▁in ▁the ▁state ▁of ▁O ax aca ▁on ▁the ▁Pacific ▁slope ▁of ▁the ▁mountains , ▁being ▁known ▁from ▁sites ▁in ▁the ▁vic inity ▁of ▁San ▁Pablo ▁Gu el ata o , ▁San ▁José ▁L ach igu ir í , ▁Un ión ▁H idal go ▁and ▁Te hu ante pec . ▁ ▁E col ogy ▁This ▁rod ent ▁is ▁found ▁in ▁and ▁near ▁the ▁head water ▁streams ▁of ▁rivers ▁in ▁tropical ▁for ested ▁areas . ▁Its ▁natural ▁history ▁is ▁poor ly ▁known , ▁but ▁it ▁seems ▁to ▁rely ▁on ▁finding ▁its ▁food ▁in ▁the ▁small ▁streams ▁among ▁closed ▁can opy ▁for ests ▁in ▁which ▁it ▁lives . ▁Other ▁members ▁of ▁R he om ys ▁are ▁also ▁sem ia qu