Sealife guideThe green spoon wormBonellia viridis
Last updated on 09/03/2025 at 11:25 PM
Taxonomy
- Common name: Green spoon worm
- French name: Bonellie verte
- Scientific name: Bonellia viridis (Rolando, 1821)
- Family name: Bonelliidae
- Order name: Echiuroidea
- Class name: Echiura
Description
The green spoon worm belongs to the phylum Echiura, a separate group of
marine worms.
The female green spoon worm only reveals its extensible proboscis, which ends in a T-shaped fork
Due to sexual dimorphism, females and males have completely different morphologies ! The female's body looks like an elongated sausage about 4 inches long on average, with a mouth that extends into a proboscis ending in a T-shaped fork. The male, on the other hand, is oval-shaped and barely a few millimeters long.
The green spoon worm produces a chemical substance called bonellin, a bright green pigment that gives it its overall color.
Geographic range
The green spoon worm is found in the Mediterranean sea and the northeastern Atlantic ocean.
Habitat
The green spoon worm lives on the seabed, with its body sheltered in rocky crevices and, more rarely, buried in sand. The male lives attached to the female. Green spoon worms are found down to depths of about 130 feet.
Diet
To feed, the green spoon worm stretches its proboscis outside its hiding place, and like a vacuum cleaner, explores the area around its shelter in search of organic debris.
Reproduction
The main characteristic of the green spoon worm is its sexual dimorphism: the female is enormously larger than the male. In fact, the male lives in symbiosis, attached to the female.
The sex of the green spoon worm is not determined at birth. After a brief planktonic stage, the larvae settle on the seabed. If they fall within the reach of a female's proboscis and come into contact with it, they become males otherwise they develop as females !
The larva attaches to the proboscis before migrating into the female's intestine and uterus, where it spends its life fertilizing eggs, becoming a true sexual slave to the female. Very often, a single female hosts many males !
Did you know ?
The green spoon worm can stretch its proboscis up to 6.5 feet long.
The green pigment of the green spoon worm has therapeutic properties that are of interest to medical researchers.
Tips for observing
There is no chance of observing a male green spoon worm while diving, since it is tiny and lives inside the female's uterus. As you've probably guessed, all the green spoon worms you'll encounter while diving are females !
The green spoon worm can stretch its proboscis up to 6.5 feet long
In most cases, you'll only see part of its anatomy, specifically, the proboscis, which stretches across the seabed in a T-shape. The rest of the female's body remains hidden in rocky crevices. Be careful: at the slightest touch, the proboscis instantly retracts !
The marine species from Mediterranean sea
Compass jellyfish
(Chrysaora hysoscella)
Cylinder anemone
(Cerianthus membranaceus)
Damselfish
(Chromis chromis)
Green spoon worm
(Bonellia viridis)
Painted comber
(Serranus scriba)
Red starfish
(Echinaster sepositus)
Ringneck blenny
(Parablennius pilicornis)
Stony sea urchin
(Paracentrotus lividus)
