The web-footed tenrec otter shrew, or aquatic tenrec (Limnogale mergulus), is an semiaquatic species of tenrec (the African otter shrews have similar habits), and is found in eastern Madagascar, especially in and around Ranomafana National Park. It grows to between 25 and 39 cm, and was once thought to be extinct. It feeds on crabs, water insects, and crayfish. It weighs between 40 and 60 grams, and the population is considered vulnerable. It is the only species in the genus Limnogale.