ISLAMABAD-A pair of newly discovered aquatic mice species - with elongated feet and water resistant fur - are amongst the ‘world’s rarest mammals’, a new study found. Researchers from the Field Museum, Chicago, say the mice are native to the remote Congo basin and evaded scientific detection due to political unrest in the area.  The two species, previously unknown to science, are related to a mouse known as ‘Nilopegamys’ - or mouse from the source of the Nile found 93 years ago in ethiopia.