Megalomys desmarestii
Megalomys desmarestii, also known as the Martinique muskrat, Desmarest's pilorie, or the Martinique giant rice rat, is an extinct rice rat from Martinique in the Caribbean. Description
It was among the largest species of West Indian rice rats, as big as a cat, and was one of the first Caribbean mammals to become extinct during the 20th century. It may have been semi-aquatic, as it was known to escape into the sea when pursued by predators, but it never swam away from the island. Extinction
It was common on Martinique until the end of the 19th century, when attempts were made to exterminate it because it was considered to be a pest of the island's coconut plantations. It was also hunted for food; however, due to its strong musky odor, this was uncommon. On 8 May 1902, the volcano Mount Pelée erupted, completely destroying the island's principal city of Saint-Pierre. It has been speculated that the rice rat became extinct then or during a later eruption in 1902, but predation by introduced small Indian mongooses is more likely to have been the primary cause of its extinction. References 

Rodent extinctions since 1500
Endemic fauna of Martinique
Megalomys
Mammals described in 1829
Taxa named by Johann Baptist Fischer
Mammals of Martinique