Photograph by Ria Tan

A Blue Button (Porpita pacifica) at Sisters Islands

Location, date and time: Singapore Straits, Big Sister Island (Pulau Subar Laut); 20 April 2014; 0845 hrs

Observation: An example with disc of about 1.5 cm diameter was found washed ashore on the beach at the mid-tide line with other flotsam. When placed into a bucket of seawater, all the blue appendages fell off the flat, white central disk. It was assumed that the animal was freshly dead.

Remarks: The Blue Button is a highly modified hydrozoan that inhabits the open seas and oceanic waters, drifting about at or near the surface. The occasional examples are stranded on reefs and beaches when brought inshore by winds or currents (Colin & Arneson, 1995: 72-73).


  • Colin, P. L. & C. Arneson, 1995. Tropical Pacific Invertebrates. A Field Guide to the Marine Invertebrates Occurring on Tropical Pacific Coral Reefs, Seagrass Beds and Mangroves. Coral Reef Press, Beverly Hills, California, USA. vii + 296 pp.

Source: Singapore Biodiversity Records 2014: 151

Giant Top Shell

Giant Top Shell (Tectus niloticus)
Pulau Subar Laut (Big Sister’s Island), 20th August 2012

Although traditionally classified as a top shell (F. Trochidae), recent studies have shown that this species is actually more closely related to the turban snails (F. Turbinidae), and may warrant inclusion in a separate family (known as Tegulidae).

This is one of many species inhabiting shores that will be surveyed as part of the Southern Expedition of the Comprehensive Marine Biodiversity Survey. Taking place from 20th May to 7th June, researchers and volunteers will be involved in collecting samples and surveying various marine habitats, in an attempt to catalogue the marine life that lives in the waters to the south of Singapore.