shelled snails text index | photo index
Phylum Mollusca > Class Gastropoda > Family Neritidae
Grey mangrove nerite snail
Nerita undulata
Family Neritidae
updated Sep 2020
Where seen?This snail is sometimes seen in large numbers in mangroves. The study by Tan & Clements (2008) found this snail on mangrove tree trunks and roots, among and under rocks in interior or coastal fringes in mangroves. Sites included: Seletar Dam, Khatib Bongsu, Lim Chu Kang, Punggol and Pulau Ketam. It was previously known as Nerita grayana.

Features: 1.5-2cm. Shell thick heavy, hemispherical, the spire sticks out more prominently than other nerites found in Singapore. Thin, regular well-developed spiralling ribs. Shell colour purplish brown also pale, often with a pattern of three darker spirals.
The flat underside may be smooth or wrinkled, white to yellowish or with orange tinge. Square notched 'teeth' (3-4) on the straight edge at the shell opening, the uppermost one is squarish. Tiny or no 'tooth' on one side of the shell opening. Operculum thick, evenly covered in tiny bumps, grayish with beige patches. Body creamy white with dark tentacles.

Sometimes confused with Waved nerites which are not found in mangroves and have one distinctly large 'tooth' on one side of the shell opening which the Grey mangrove nerite does not.

Kranji, Mar 13

Grey mangrove nerite snails on Singapore shores
On wildsingapore flickr


  • Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore (pdf), Raffles Museum of Biodiversity Research, National University of Singapore.
  • Tan, S.K. & Clements, R. (2008) Taxonomy and distribution of the Neritidae (Mollusca: Gastropoda) on Singapore. Zoological Studies 47(4): 481-494.
  • Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008