shelled snails text index | photo index
Phylum Mollusca > Class Gastropoda
Sundial snails
Family Architectonicidae
updated Oct 2016

Where seen? These beautiful snails are rarely seen on our shores. They are found in tropical to warm-temperate regions near their prey.

Features: An unmistakable snail, the shell coils usually forming a flat disc-shaped with a flat base. This shape allows the snails to burrow through sand. The operculum is made of a horn-like material. Head with a short snout and a pair of long, tapering and very slender tentacles bearing eyes at their outer bases.The end of the the foot has two pointed lobes. The body is striped to match the shell.

What do they eat? They feed on sea anemones, corals and zoanthids. The mouth region is lined with a tough cuticle as a protection against stings of their prey.

Sundial babies: The snails are simultaneous hermaphrodites. Eggs are numerous, laid in capsules and embedded in a gelatinous mass anchored to the substrate, hatching as planktonic larvae. Pelagic larval stages often long, hence the snails have a very wide distribution.

Human uses: They are occasionally collected by shrimp trawlers, consumed by fishermen and used as decorative items in the shellcraft industry.

Status and threats: The Clear sundial snail (Architectonica perspectiva) is listed as 'Endangered' in the Red List of threatened animals of Singapore. The original shores where they were found have been lost to reclamation.
   

Family Architectonicidae recorded for Singapore
from Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore..
in red are those listed among the threatened animals of Singapore from Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. Nature Society (Singapore). 285 pp.
+from our observation

  Family Architectonicidae
  Architectonica perdix (Partridge sundial snail)
Architectonica perspectiva
(Clear sundial snail) (EN: Endangered)

Heliacus caelatus
Heliacus costatus
Heliacus stramineus

+Heliacus variegatus (Variegated sundial snail)

Links
  • Family Architectonicidae on The Gladys Archerd Shell Collection at Washington State University Tri-Cities Natural History Museum website: brief fact sheet with photos.
  • Family Architectonicidae in the Gastropods section by J.M. Poutiers in the FAO Species Identification Guide for Fishery Purposes: The Living Marine Resources of the Western Central Pacific Volume 1: Seaweeds, corals, bivalves and gastropods on the Food and Agriculture Organization of the United Nations (FAO) website.

References

  • Tan Siong Kiat & Chan Sow-Yan. 31 Aug 2017. Recent sightings of two species of sundial shells at eastern Singapore. Singapore Biodiversity Records 2017: 116-118.
  • 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.
  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. Nature Society (Singapore). 285 pp.
  • Abbott, R. Tucker, 1991. Seashells of South East Asia. Graham Brash, Singapore. 145 pp.
  • Gosliner, Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii exclusive of the vertebrates Sea Challengers. 314pp.
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