|A shell of Amphibola crenata|
Amphibola crenata (tītiko in the Māori language or mud-flat snail in English) is a species of air breathing snail with an operculum, a pulmonate gastropod mollusc which lives in a habitat that is intermediate between the land and the sea, not entirely terrestrial and not entirely marine. 
The thick shell of this species is about 20 mm in size.
Amphibola crenata is a curiosity, as it seems to represent a transitional state between marine and terrestrial gastropods. The mantle is employed as a lung, and therefore immersion of the animal in sea water is of secondary importance, and occurs for not more than an hour at each high tide.
This snail is a detritus or deposit feeder. It extracts bacteria, diatoms and decomposing matter from the surface sand. It egests the sand and a slimy secretion that is a rich source of food for bacteria.
In the past this species was an important food for the Māori.
- Schumacher H. C. F. (1817). Essai Vers test. 58: 190.
- Rosenberg, G. (2011). Amphibola crenata (Gmelin, 1791). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=590660 on 2012-04-06
- Powell A. W. B. (1979). William Collins Publishers Ltd, Auckland, New Zealand, ISBN 0-00-216906-1
- Rosenberg, G. 1992. Encyclopedia of Seashells. Dorset: New York. 224 pp. page(s): 125
- Golding R.E., Ponder W.F. & Byrne M. 2007. Taxonomy and anatomy of Amphiboloidea (Gastropoda: Heterobranchia: Archaeopulmonata). Zootaxa 1476: 1-50