Bearded Fireworm

“Each body segment of the bearded fireworm has hollow venom-filled bristles, which break off after penetrating flesh.”

Summary

The bearded fireworm (Hermodice carunculata) is a flat, segmented bristle worm that lives in the tropical waters of the Atlantic Ocean and the Mediterranean Sea. You can find them resting under stones in rocky areas or seagrass or feeding on corals near the water’s surface. These worms are venomous and produce a powerful neurotoxin that can debilitate their predators and cause adverse reactions in humans. Discover everything there is to know about the bearded fireworm, including where it lives, what it eats, and how it threatens a sensitive marine species.

5 Amazing Bearded Fireworm Facts

• People who accidentally brush past a bearded fireworm can exhibit symptoms like irritation, burning, nausea, and dizziness. You can remove the spines by covering them with adhesive tape.
• They emit bioluminescence during their mating ritual.
• The bearded fireworm is a distinctive creature featuring colorful segmented bodies and white silks.
• The white bristles that protrude from their bodies are hollow and filled with venom.
• They remove the tissue from the coral, leaving them exposed to algae and disease.

Classification and Scientific Name

The bearded fireworm (Hermodice carunculata) belongs to the Annelida phylum (segmented worms) in the Polychaeta class, which encompasses marine worms known as bristle worms. Their Aciculata order is a subspecies of bristle worm found in aquatic environments and brackish water. The Amphinomidae family comprises the marine polychaetes, with many species featuring stiff bristles mineralized with carbonate. And lastly, they belong to the Hermodice genus, a group of annelids with a cosmopolitan distribution.

Appearance

Bearded fireworms are flattened segmented worms with an average length of 6 inches. But they can grow as large as 12 inches. Their coloring varies and can range from yellow to red, green, and white. They look similar to a centipede and feature white silks, lateral body protrusions (parapodia), and red or orange gills on the side of their body. Each body segment (there are between 60 to 150) has hollow white bristles filled with venom, which break off after penetrating flesh. They also feature small growths called caruncles on the anterior portion that are also red or orange, like the gills. 

These worms get their name from the burning sensation they produce in their victims upon contact with their bristles. These bristles flare out when they are disrupted, so they are further exposed. While their toxin is effective in debilitating their marine predators, they are relatively harmless to humans. However, coming in contact with their neurotoxin can produce extreme irritation and a painful burning sensation around the injection site.

Distribution, Population, and Habitat

It is native to the tropical waters of the Atlantic Ocean and the Mediterranean Sea, primarily around the coasts, from Algeria to Liberia and along the United States’ southeast coast down to South America’s northern tip. You can also find them in the Gulf of Mexico and the Caribbean Sea. They live on reefs, rocky areas, seagrass, and muddy bottoms. Look for them under stones or resting on top of reef beds in shallow water near the surface and as deep as 130 feet. 

Evolution and History

The first polychaetes date back 505 million years ago, during the Cambrian Period. Their ancestors also featured feather-like bristles and sensory tentacles attached to their heads. But what’s truly fascinating is that these creatures survived five mass extinctions, making way for the abundance of marine worms that exist today. 

Predators and Prey

Bearded fireworms are marine predators that eat coral (hard and soft), small crustaceans, and anemones. They place coral tips into their inflated pharynx and remove the tissue, spending around five minutes at each branch. This species can be quite damaging, feeding on endangered coral and exposing them to disease. Fireworms prefer to prey on corals but they will also consume squid, krill, shrimp, clam, and mussels in captivity. Most marine creatures ignore these worms, but several species, like white grunts and sand tilefish, feast on bearded fireworms when encountered.

Reproduction and Lifespan

The bearded fireworm can reproduce through asexual and sexual means. They can undergo fragmentation, where their bodies divide into separate parts and regenerate to become new individuals. But they can also reproduce through regular spawning, which typically occurs two to five days after a full moon. Females emit a phosphorescent glow, attracting males to the surface, where they flash their colors, as well. As they move toward each other, they shed and combine their sex cells. They live for an average of two to three years.

Threats and Conservation Status

The conservation status of the bearded fireworm is not listed in the International Union for Conservation of Nature database. Their status and population size are unknown. Not enough research has been conducted on this species to know what threatens them. However, bearded fireworms are a known threat to coral reef systems in their range.

Locations:

• Atlantic Ocean
• Mediterranean Sea
• Gulf of Mexico
• Caribbean Sea

Related Animals

• Antarctic Scale Worm
• Coral
• Invertebrates

1. Lamar.edu, Available here: https://www.lamar.edu/arts-sciences/biology/study-abroad-belize/marine-critters/marine-critters-2/fireworm.html
2. ESA Journals, Available here: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/fee.1305#:~:text=Beneath%20many%20of%20the%20platforms,Figure%201%20and%20WebVideo%201
3. Smithsonian Magazine, Available here: https://www.smithsonianmag.com/science-nature/14-fun-facts-about-marine-bristle-worms-180955773/
4. NCBI, Available here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5778601/
5. T and F online, Available here: https://www.tandfonline.com/doi/abs/10.1080/10236244.2018.1502031?cookieSet=1