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Phylum Mollusca > Class Gastropoda > Family Muricidae
Dark drill
Semiricinula fusca
Family Muricidae
updated Oct 2016

Where seen? This small drill is sometimes seen on large boulders on some of our shores. 'Fuscus' means dusky, dark or swarthy, probably referring to the dark coloured shell opening. According to Tan, it has a patchy distribution in Singapore but can be common where it occurs. It is also known as Morula fusca.

Features: 2-3cm. Shell thick with squarish bumps. Shell opening is wide and usually dark to dark purple. One of the identifying features is its yellow foot.

What does it eat? According to Brian Ong's study, those on St. John's Island were found to eat false limpets: Siphonaria javanica and Siphonaria guamensis. They also rarely ate small bivalves and barnacles. In Brian's study, found that the snail drills a hole through the shell of the false limpet, or by slipping its proboscis under the shell of the false limpet. Brian found that they were not selective about the size of their prey.

Baby drills: This snail lays stalked, globular egg cases. Tiny crawling juvenile snails emerge from these egg cases.

Chek Jawa, May 05

Labrador, May 06

Sisters Island, Feb 11

Chek Jawa, May 05

Photo shared by Brian Ong.

Photo shared by Brian Ong.

Hole drilled into a false limpet, by the drill.
Photo shared by Brian Ong.

*Species are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.

Dark drills on Singapore shores

Photos of Dark drills for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Acknowlegement
With grateful thanks to Brian Ong for identification and information about these fascinating snails.

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 Singapore.
  • Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
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