Rare Shiny Snail Reappears Off Israel’s Shores

The creature was last seen nearly 40 years ago and shines at night as a way to communicate and spook predators.

A shiny snail of the genus Plocamopherus, off Achziv in northern Israel, April 2015.
Shevy Rothman

One of the rarest types of snail in the Mediterranean and Red Sea, the shiny Plocamopherus, has been photographed near Israel’s coast for the first time in nearly four decades. Only 30 have been documented since the genus was designated almost 200 years ago.

The recent sightings have been reported by Dr. Bella Galil of the Israel Oceanographic and Limnological Research Institute in Haifa and Shevy Rothman of Tel Aviv University’s Zoology Department. Their findings have been reported in this month’s edition of Marine Biodiversity Records.

According to Galil and Rothman, the snail, which originates in the Red Sea, was spotted off the coast of Nahariya and near the breakwater at Ashdod. In 1977, Galil saw one dozens of meters deep near the Nitzanim beach north of Ashkelon. This time rows of eggs were on hand, suggesting the population was stable and managing to reproduce.

The Plocamopherus is a slug without an external shell; it has an endoskeleton instead. It also shines at night, a fact discovered by researchers a hundred years ago in the Suez Canal. This helps the creatures communicate, but it also deters predators.

The snail feeds on invertebrates that stick to rocks or the hulls of boats. The snails apparently relied on ships in the Mediterranean for food and spreading their reach.

In recent decades, the snails probably spread from Israel to Lebanon and Turkey. Since their number is small they eluded researchers and photographers until they started multiplying more rapidly.

It’s possible the original population disappeared and the new ones reached the Mediterranean through the Suez Canal.