Gastropods · Cephalaspidea · Hydatinidae

Brown-line Paperbubble

Hydatina physis

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

A bubble snail with a pink mantle with a wavy edge and a translucent shell crossed by fine brown lines. Its body is so bulky that it does not fit inside the shell. It feeds on polychaete worms, which it finds by following their trails through the sand.

Size

2 cm – 7 cm

Diet

Carnivore

Feeds mainly on other animals.

Activity

Nocturnal

Active mainly at night.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Unknown

OceanCarnivore Nocturnal Solitary Ocean Mollusc

61countries 161dive sites

Fun facts

The mantle, deep pink with a bluish-white margin, wraps almost the whole shell when the animal is active.
Its shell is extremely thin and translucent, with brown spiral bands, and it is almost covered by a pink, ruffled mantle with a shining edge, which gives it an appearance very unlike a snail's.
It is a specialised predator: it eats polychaete worms, above all from the cirratulid group, which it locates beneath the sand and swallows whole.
Its body is too big to fit in the shell, so it cannot retract: it depends on burying itself to escape.
It is a hermaphrodite, and its egg masses are coiled gelatinous strings that it fixes to the sand.
Like the striate bubble, it illustrates the evolutionary transition towards the loss of the shell in the opisthobranchs.