Terebralia palustris

Terebralia palustris, commonly known as the giant mangrove whelk, is a species of brackish-water snail, a mollusk in the family Potamididae. This tropical species which inhabits mangrove environments of the Indo-West Pacific region, has the widest geographic distribution amongst the potamidids extending from eastern Africa to northern Australia. Terebralia palustris is the largest mangrove gastropod, with a maximum shell length of 190 mm recorded from Arnhem Land, Australia.