Any worm that lives in a marine environment is considered a marine worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida, Chaetognatha, Hemichordata, and Phoronida. For a list of marine animals that have been called "sea worms", see sea worm.
Polychaeta is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm and the sandworm or clam worm Alitta.
A chaeta or cheta is a chitinous bristle or seta found in annelid worms,. Polychaete annelids, are named for their chaetae. In Polychaeta, chaetae are found as bundles on the parapodia, paired appendages on the side of the body. The chaetae are epidermal extracellular structures, and clearly visible in most polychaetes. They are probably the best studied structures in these animals.
The acorn worms or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in the world, the main species for research being Saccoglossus kowalevskii. Two families—Harrimaniidae and Ptychoderidae—separated at least 370 million years ago.
Chaetopterus pugaporcinus, commonly known as the pigbutt worm or flying buttocks, is a species of worm first described by scientists at the Monterey Bay Aquarium Research Institute in 2007. The worm is round in shape, approximately 10 to 20 millimeters in length, and bears a strong resemblance to a disembodied pair of buttocks. Because of this, it was given a Latin species name that roughly translates to "resembling a pig's rear."
Polynoidae is a family of marine Polychaete worms known as "scale worms" due to the scale-like elytra on the dorsal surface. Almost 900 species are currently recognised belonging to 9 subfamilies and 167 genera. They are active hunters, but generally dwell in protected environments such as under stones. The group is widely distributed from shallow intertidal waters to hadal trenches. They are the most diverse group of polychaetes in terms of genus number and second most diverse in terms of species number which is almost 8% of all segmented worm species.
The Chaetopteridae are a family of marine filter-feeding polychaete worms that live in vertical or U-shaped tubes in tunnels buried in the sedimentary or hard substrate of marine environments. The worms are highly adapted to the hard tube they secrete. Inside the tube the animal is segmented and regionally specialized, with highly modified appendages on different segments for cutting the tunnel, feeding, or creating suction for the flow of water through the tube home. The modified segments for feeding are on the 12th segment from the head for members of this family.
Terebellida make up an order of the Polychaeta class, commonly referred to as "bristle worms". Together with the Sabellida, the Spionida and some enigmatic families of unclear taxonomic relationship, they make up the subclass Canalipalpata, one of the three main clades of polychaetes. Like most polychaetes, almost all members of the Terebellida are marine organisms. Most are small, sessile detritivores which live in small tubes they build from mud or similar substrate, or burrow in the sand. Their central nervous system displays characteristic apomorphies.
Swima bombiviridis is a worm species that lives in the deep ocean. It is also known as the green bomber worm, green bomber worm, or bombardier worm. This deep ocean pelagic (free-swimming) annelid has modified bioluminescent gills that can be cast off from an individual. These discarded gills somewhat resemble green "bombs" that remain illuminated for several seconds after they have been discarded. It is thought that this is a defensive mechanism rather than reproductive, as it is seen in both mature and juvenile individuals. This species was the first of its genus, Swima, to be discovered, and was the only one with a formal scientific name as of 2010. The genus name, Swima, is derived from the Latin, referring to the animal's ability to swim. The species name, bombiviridis, is derived from the Latin prefix bombus, meaning humming or buzzing, and the suffix viridis, which is Latin for the color green. Swima bombiviridis therefore translates to "swimming green bomber".
Swima is a genus of marine polychaete worms found in the ocean at depths between 1,800 and 3,700 meters. Even if they are agile swimmers, they are often seen hanging immobile in the water column as they are neutrally buoyant. This deep ocean pelagic (free-swimming) genus has modified bioluminescent gills that can be cast off from an individual. These discarded gills somewhat resemble green "bombs" that remain illuminated for several seconds after they have been discarded. It is thought that this is a defensive mechanism rather than reproductive, as it is seen in both mature and juvenile individuals. And because they are eyeless, communicating with light would be difficult. Swima worms are closely related to the recently discovered genus Teuthidodrilus, another pelagic cirratuliform of the bathyal zone.
Serpula is a genus of sessile, marine annelid tube worms that belongs to the family Serpulidae. Serpulid worms are very similar to tube worms of the closely related sabellid family, except that the former possess a cartilaginous operculum that occludes the entrance to their protective tube after the animal has withdrawn into it. The most distinctive feature of worms of the genus Serpula is their colorful fan-shaped "crown". The crown, used by these animals for respiration and alimentation, is the structure that is most commonly seen by scuba divers and other casual observers.
Acrocirridae is a family of polychaete worms. Acrocirrids are detritivores, catching falling particles with numerous long prostomial tentacles. There are eight known genera, and at least 21 described species and subspecies within the Acrocirridae. The acrocirrids are primarily benthic (seabed-dwelling) animals, but at least two genera appear to have evolved or adapted to a pelagic (free-swimming) habitat.
Yoda purpurata is a species of acorn worm discovered 2.5 km below the surface of the Atlantic ocean, and was the first of the genus Yoda found. Ranging from 12 to 19 cm in length, it was named after the fictional character Yoda from the Star Wars franchise. It was the first known hermaphroditic member within the phylum. The other known hermaphroditic member of the phylum is Yoda demiankoopi discovered in 2021.
Torquaratoridae is a family of acorn worms (Hemichordata) that lives in deep waters between 350 to 4000 meters. They can grow up to three feet in length and have semitransparent gelatinous bodies, often brightly colored.
The annelids, also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments.
Marilyn "Marian" Hope Pettibone (1908–2003) was a curator at the Smithsonian's National Museum of Natural History invertebrate zoology department. She was known for her work on worms, specializing in polychaetes. She was the world authority on polynoidae during her career.
Imants (Monty) George Priede is a British-Latvian zoologist, author and academic. He is Professor Emeritus in the University of Aberdeen, Scotland known for his work on fish and life in the deep sea.
Subadyte pellucida is a scale worm widely reported from the Indian, Pacific and North Atlantic Oceans from the intertidal zone to depths of about 800 m.
Flotidae is a family of pelagic polychaete worms, sometimes synonymized with Flabelligeridae, which they closely resemble. Other sources consider them the sister taxon to Flabelligeridae and closely allied to the latter group.
