| Leocratides | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Clade: | Pleistoannelida |
| Subclass: | Errantia |
| Order: | Phyllodocida |
| Family: | Hesionidae |
| Subfamily: | Hesioninae |
| Genus: | Leocratides Ehlers, 1908 |
| Species | |
L. kimuraorum | |
| Synonyms | |
Leocrates (superseded) | |
Leocratides is a genus of marine hesionid polychaete worms [1] dwelling in hexactinellid sponges. [2]
A superseded synonym of the genus is Leocrates. Its parent group is Hesionini, a tribe in the subfamily Hesioninae. [1]
The three known species include L. kimuraorum , L. ehlersi, and L. filamentosus. [1] [2]
The Japanese name of Leocratides is hanakago-otohime-gokai-zoku. [2]
The taxonomy of the genus has been debated by invertebrate zoologists since L. filamentosus was first discovered by the German zoologist Ernst Ehlers in 1908 on the deep-sea Valdivia Expedition. When R. Horst described L. ehlersi for the first time in 1921, examining an old specimen from the Siboga expedition, he suggested that the two known species were distinguished by having one or two dorsal jaw plates. Based on a 1926 analysis however, H. Augener argued that L. ehlersi was a junior synonym of L. filamentosus, and that both had two upper jaw plates. In 1970, Marian Pettibone once again re-described both species in detail and concluded they were synonymous. [2] Yet, in 1998, Fredrik Pleijel restored L. ehlersi as a distinct species again. [3] The distinguishing features between L. filamentosus and L. ehlersi are that the former has pharyngeal terminal papillae and a papillose peristomial membrane, while the latter lacks them. Pleijel's interpretation in 1998 has held up to the present, being reconfirmed in 2017. [2]
In 2017, a new species, L. kimuraorum was described by Naoto Jimi, Masaatsu Tanaka, and Hiroshi Kajihara, who also extended the range of L. filamentosus to Sagami Bay. [2] In 2019, L. kimuraorum was discovered to produce a uniquely loud clicking sound during conspecific 'mouth-fights'. [4] Media sources named it a "mouth fighting worm" or "tiny fighting worm". [5] L. kimuraorum is distinguished by remarkably long antennae as long as palps, by the presence of pharyngeal terminal papillae in common with L. filamentosus, and by the absence of a papillose peristomial membrane in common with L. ehlersi. [2]
Worms of the genus Leocratides are marine organisms like almost all polychaetes (bristle worms). Body size is generally 21–50 millimetres (0.83–1.97 in). As larvae, they are zooplankton. They become benthos as adults. [1]
The worms inhabit Aphrocallistes sp. hexactinellid sponges. Their ecology with their sponge hosts is not entirely known, but they probably feed on the sponges. Mouth-fighting in one species may serve as territorial competition over the sponge. [6]
They live at depths from 74–677 meters (243–2,221 ft). They were initially discovered in the sublittoral zone, above the dropoff of the continental shelf, but more recently have been discovered at greater depths. [2]
Species of Leocratides inhabit the Indian and Pacific Oceans. They are known from the Red Sea (L. ehlersi), [1] and off the coasts of Indonesia (L. filamentosus) and Japan (L. filamentosus and L. kimuraorum). [2]
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.
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.
Hesionidae are a family of phyllodocid "Bristle worms". They are marine organisms. Most are found on the continental shelf; Hesiocaeca methanicola is found on methane ice, where it feeds on bacterial biofilms.
Swima bombiviridis is a worm species that lives in the deep ocean. It is also known as the 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.
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.
Kirk J. Fitzhugh is the curator at the Natural History Museum of Los Angeles County, a position he has held since 1990. His research focuses on the systematics of polychaetes and on the philosophical foundations of evolutionary theory. Fitzhugh is a critic of DNA barcoding methods as a technical substitute for systematics. He attends Willi Hennig Society meetings where he has argued that "synapomorphy as evidence does not meet the scientific standard of independence...a particularly serious challenge to phylogenetic systematics, because it denies that the most severely tested and least disconfirmed cladogram can also maximize explanatory power." His graduate supervisor was V. A. Funk, from the U.S. National Herbarium, National Museum of Natural History, Smithsonian Institution MRC. He completed his doctoral thesis on Systematics and phylogeny of Sabellid polychaetes in 1988 while he was a research scientist at the LA County museum He married a lawyer named Nancy E. Gold in 1989.
Eulalia is a genus of polychaete worms.
Syllis ramosa is a species of polychaete worm in the family Syllidae. It is found in the deep sea where it lives within the tissues of a sponge. It was the first branching polychaete worm to be discovered, with each worm having a single head and multiple anuses.
Ramisyllis multicaudata is a species of polychaete worm in the family Syllidae. It was found in Darwin Harbour, Australia, where it was living within the tissues of a sponge of the genus Petrosia. It was the second branching species of polychaete worm to have been discovered, the first having been Syllis ramosa, a deep water species, more than a century earlier. In 2022, a second species in R. multicaudata's genus, Ramisyllis kingghidorahi, was described from specimens taken off the coast of Sado Island, Japan.
Eulagisca gigantea is a species of scale worm. This species is specifically found in the deep-sea in cold waters like the Antarctic Ocean. The scale worms are named for the elytra on their surface that look like scales.
Aberranta is a genus of polychaete thought to be related to the Nerillidae.
Metabonellia is a genus of marine spoon worms in the family Bonelliidae. It is a monotypic genus and Metabonellia haswelli is the only species. It is commonly known as the green spoon worm and is found in shallow waters around Australia.
Thysanocardia procera is a marine invertebrate belonging to the phylum Sipuncula, the peanut worms. It is a cylindrical, unsegmented worm with a crown of tentacles around the mouth. It is native to shallow seas in the northeastern Atlantic Ocean.
Leocratides kimuraorum is a species of marine worm belonging to Hesionidae, which is known for the intensity of its intraspecific fighting. Its body is nearly translucent and up to 29 millimetres (1.1 in) long.
Phyllodoce lineata is a species of polychaete worm in the family Phyllodocidae. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea where it occurs in the intertidal and shallow sub-tidal zones on soft sediment.
Ramisyllis kingghidorahi is a species of polychaete worm in the family Syllidae. The species lives in the Sea of Japan off Sado Island, Japan, where the holotype was found living within the internal canals of a sponge of the genus Petrosia.
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Diopatra claparedii is a species of tube-building polychaete worm of the family Onuphidae. It is found dispersed along intertidal and subtidal benthic environments of South Asian waters, especially along the coasts of Malaysia, Singapore, Thailand, and the Philippines. This species is exploited by humans for fishing bait, indication of marine pollution, and as gold and silver nanoparticle biosynthesis agents.
Notophyllum foliosum is a species of annelid in the family Phyllodocidae. Roughly 12 millimeters long, the annelid is bristly and covered in scale-like cirri. The species is found in shallow areas of the seafloor of the Mediterranean, Scandinavia, and Madeira. It was originally described as Phyllodoce foliosa in 1835 and was moved to the genus Notophyllum in 1923. The species was split in two in 2010, with the deeper-dwelling Notophyllum crypticum being designated its own species.
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