| 
        
          
            | Knobbly 
            periwinkle snail Echinolittorina malaccana
 Family Littorinidae
 updated Aug 2020
 Where 
            seen? This tiny snail with a knobbly shell is sometimes 
            seen on some of our rocky shores. In  groups on boulders near 
            the high water mark, often wedged into crevices and cracks at low 
            tide. It was previously known as  Nodilittorina trochoides and Nodilittorina pyramidalis.
 
 Features: 0.8-1cm. Shell thin with spirals of tiny knobs. 
            Colours variable, often bleached white. Operculum  thin, circular, made 
            of a horn-like material.
 
 Tiny but tough: This tiny snail is able to withstand high temperatures. It is even hardier than  
            other kinds of periwinkles. 
            It is believed that the knobbly texture of the 
            shell helps to keep the animal cool. It is often found so high up on 
            the rocks that it is only wet for a few hours for the few days 
            of high spring tides every two weeks or so. This tough snail feeds 
            only during these high spring tides or perhaps when it rains.
 |  
         
          |  St. John's Island, Feb 11
 |  |  
        
          |  Lazarus Island, Jul 04
 |  Chek Jawa, 
              May 05
 |  Chek Jawa, 
          May 05
 |  
        
          
            | Human 
                    uses: Surprisingly, even though it is so tiny, this snail is said to be collected 
                    for food and the shell trade especially in Vietnam and the 
            Gulf of Thailand. |  
 
        
          
            | Knobbly 
      periwinkle snails on Singapore shores |  
 
         
          | Links References 
                
              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 SingaporeTan, K. S. 
                & L. M. Chou, 2000. A 
                Guide to the Common Seashells of Singapore. Singapore 
                Science Centre. 160 pp. |  |  |