On the Underwater Trail of Venomous Snails

SCIENTISTS ESTIMATE that there are 300 to 400 different species of terebrid snails — a type of venomous marine snail — that live in tropical environments around the globe. So far, only 150 species have been identified from DNA analysis. Some terebrids are equipped with a venom apparatus that produces compounds that could be used for drug development.

Mandë Holford boarding plane to Madang, Papua New Guinea, for the expedition. Below, assortment of cone snails collected.

Mandë Holford boarding plane to Madang, Papua
New Guinea, for the expedition. Below, assortment of cone snails collected.

Hunter College chemistry professor Mandë Holford spent a month in the fall in Papua New Guinea searching for new species of the snails for molecular analysis. The expedition was in collaboration with the Paris Museum of Natural History.

fieldconessiloHolford and her research partners are working on building a family tree of marine snails, which could be used as a road map to identify lineages that produce toxins. They had found 30 new terebrid snail species for molecular analysis on another expedition to Mozambique in 2009.

“We can use the family tree on an expedition as a road map to try to target the specific snails that we need,” says Holford, a York College graduate who has a doctorate in synthetic protein chemistry from Rockefeller University.

In Papua New Guinea, Holford dived, snorkeled and dredged the waters to discover 17 new species for molecular analysis. But to find which of the terebrids had venom, Holford had to crack open the shell of each one, searching for a venom gland. Of the new species, she found eight that had a gland to produce peptide toxins.

“We had to sacrifice them all because they were new species and we didn’t know which ones are toxic,” says Holford, also a research scientist at the American Museum of Natural History. “But that’s good progress for our research. We’re getting closer to total representation of the 400 estimated species in our snail family tree.”

The Papua New Guinea expedition was part of a larger, “Our Planet Reviewed” project, partly funded by Prince Albert II of Monaco, who visited with the 120 scientists who participated in the latest expedition.


Sorting through the dredge sample in the Madang lagoon. Holford with local
Papua New Guinea students and a student from New Caledonia.


The laboratory at the Divine Word University where specimens collected in the field are analyzed daily.


Banana boats filled with scientists ready to go into the field


Holford shows Prince Albert II of Monaco, a funder of the expedition, how venom is extracted from a snail’s glands with the aid of a microscope.