Mud Creeper / Mangrove Whelk

Description:

Terebralia palustris (Linnaeus, 1767) is the largest snail species commonly reaching 120mm in length, and occasionally as much as 190mm.The shell is thick and heavy, sculptured by 4 flat, spiral ribs on each whorl, and by longitudinal ribs that become indistinct on the final whorl.When maximum size is reached the aperture becomes slightly flared, and there is a short, open canal at the anterior end.The columellar pillar bears 2 spiral folds, but these are not visible from the aperture. Opposite the aperture there is a thick longitudinal boss (varix) with internal teeth, and smaller varices are scattered on the spire whorls.The operculum is round, corneous and multispiral.The foot is dark brown, and the broad snout and cephalic tentacles are black. The edge of the mantle forming the inhalent siphon bears a light-sensitive pit, and the gills are reduced.The sexes are separate, and there is no penis.In addition to its larger size, it can be distinguished from other similar potamidid snails by the flared aperture of the adult shell, which does not fully enclose the anterior canal, leaving the canal as a deep groove (rather than an encircled tube).Juveniles can be distinguished from adult snails not only by their smaller size, but by the thin growing edge of the shell - the aperture becomes thickened and flared only when final adult size is attained.

Habitat:

These snails are found in mangrove habitats - these were in iSimangaliso Wetland Park, a huge protected area along the coast of South Africa’s KwaZulu-Natal Province.

Notes:

aka - the giant mangrove whelk, a species of brackish-water snail, a gastropod 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.