Prof. Dr. Peter Wirtz, Madeira
Info
The green Bonellia viridis has a smooth surface.
The worm is dioecious. The female's egg-shaped body grows to a length of 15 cm. In contrast, the proboscis is thin like a ribbon and reaches an impressive length of 1.50 m. The end of the long proboscis is forked.
The color of Bonellia viridis ranges from intense green to dark green. It is also described as emerald green.
The male is built very differently from the female. Males only grow to a size of 2.5-3 mm. The worms we see are all female, because the tiny male worm swims in the female's body cavity and fertilizes the eggs there. After fertilization, the females release the eggs into the open water.
The worm itself is often hidden under stones. Plankton is filtered out of the water with its long proboscis.
The green sea cucumber is predominantly nocturnal.
This bright green marine creature contains a toxic pigment that protects it from predators, kills bacteria, and determines the sex of the larvae by turning males into a “living testicle sac.”
Name: Green spoon worm (Bonellia viridis)
Habitat: Seafloors in the northeast Atlantic, from the Mediterranean to northern Norway
Food: Organic matter and small invertebrates filtered from the water
Why it's so cool: Green spoon worms are named for their spoon-shaped proboscis—a long, sucking mouthpart used for feeding—which extends into the water to catch passing food.
“They basically look like a tentacle monster from a science fiction movie,” Trond Roger Oskars, a researcher specializing in marine invertebrates at the Møreforsking Research Institute, said in an email to Live Science.
The rest of their thick, sausage-shaped bodies remain buried in the seafloor — sometimes in burrows created by other animals — while their ribbon-like proboscis flutters in the water to fish for tiny bits of organic matter to eat, including algae, decaying material, and even feces. “They're like vacuum cleaners sweeping across the seafloor,” Oskars said.
While green spoonworms' bodies are about 6 to 7 inches long, “that wavy proboscis can be up to ten times longer,” he said.
Their iconic bright green color, which comes from a toxic pigment called bonellin, warns predators to stay away. But not all green spoon worms look like this. “Here's the kicker!” Oskars said. “The green ones you see are only the females.”
An individual's sex depends more on chemistry than genetics. When a larva swims through the ocean and settles on the sea floor, it develops into a female. However, if a larva lands on a female, it reacts to the bonellin in her body and turns into a male. Like some species of anglerfish, these males are microscopic and are absorbed into her body, where they become parasites whose sole purpose is to fertilize her eggs. “Basically, it's reduced to a living testicle,” he said.
Related topics: “Parasitic sperm supplier”: Why the sex lives of deep-sea animals require extreme solutions
Bonellin not only protects spoon worms from predators and turns males into living gonads, but also kills bacteria.
“It is being considered as a potential new antibiotic, but it could also offer a whole range of other interesting applications,” Oskars said. “They are a prime example of why we need to know more about strange creatures and their habitats ... We only know 10% of the species in the ocean. Who knows what other creatures are hiding there and offering additional benefits?”
The worm is dioecious. The female's egg-shaped body grows to a length of 15 cm. In contrast, the proboscis is thin like a ribbon and reaches an impressive length of 1.50 m. The end of the long proboscis is forked.
The color of Bonellia viridis ranges from intense green to dark green. It is also described as emerald green.
The male is built very differently from the female. Males only grow to a size of 2.5-3 mm. The worms we see are all female, because the tiny male worm swims in the female's body cavity and fertilizes the eggs there. After fertilization, the females release the eggs into the open water.
The worm itself is often hidden under stones. Plankton is filtered out of the water with its long proboscis.
The green sea cucumber is predominantly nocturnal.
This bright green marine creature contains a toxic pigment that protects it from predators, kills bacteria, and determines the sex of the larvae by turning males into a “living testicle sac.”
Name: Green spoon worm (Bonellia viridis)
Habitat: Seafloors in the northeast Atlantic, from the Mediterranean to northern Norway
Food: Organic matter and small invertebrates filtered from the water
Why it's so cool: Green spoon worms are named for their spoon-shaped proboscis—a long, sucking mouthpart used for feeding—which extends into the water to catch passing food.
“They basically look like a tentacle monster from a science fiction movie,” Trond Roger Oskars, a researcher specializing in marine invertebrates at the Møreforsking Research Institute, said in an email to Live Science.
The rest of their thick, sausage-shaped bodies remain buried in the seafloor — sometimes in burrows created by other animals — while their ribbon-like proboscis flutters in the water to fish for tiny bits of organic matter to eat, including algae, decaying material, and even feces. “They're like vacuum cleaners sweeping across the seafloor,” Oskars said.
While green spoonworms' bodies are about 6 to 7 inches long, “that wavy proboscis can be up to ten times longer,” he said.
Their iconic bright green color, which comes from a toxic pigment called bonellin, warns predators to stay away. But not all green spoon worms look like this. “Here's the kicker!” Oskars said. “The green ones you see are only the females.”
An individual's sex depends more on chemistry than genetics. When a larva swims through the ocean and settles on the sea floor, it develops into a female. However, if a larva lands on a female, it reacts to the bonellin in her body and turns into a male. Like some species of anglerfish, these males are microscopic and are absorbed into her body, where they become parasites whose sole purpose is to fertilize her eggs. “Basically, it's reduced to a living testicle,” he said.
Related topics: “Parasitic sperm supplier”: Why the sex lives of deep-sea animals require extreme solutions
Bonellin not only protects spoon worms from predators and turns males into living gonads, but also kills bacteria.
“It is being considered as a potential new antibiotic, but it could also offer a whole range of other interesting applications,” Oskars said. “They are a prime example of why we need to know more about strange creatures and their habitats ... We only know 10% of the species in the ocean. Who knows what other creatures are hiding there and offering additional benefits?”
