| Nereididae | |
|---|---|
 | |
| Alitta succinea | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Clade: | Pleistoannelida |
| Subclass: | Errantia |
| Order: | Phyllodocida |
| Suborder: | Nereidiformia |
| Family: | Nereididae Fauchald, 1977 |
Nereididae (formerly spelled Nereidae) are a family of polychaete worms. It contains about 500 – mostly marine – species grouped into 42 genera. They may be commonly called ragworms or clam worms.
The prostomium of Nereididae bears a pair of palps that are differentiated into two units. The proximal unit is much larger than the distal unit. Parapodia are mostly biramous (only the first two pairs are uniramous). Peristomium fused with the first body segment, with usually two pairs of tentacular cirri. The first body segment with 1-2 pairs tentacular cirri without aciculae. Compound setae are present. Notopodia are distinct (rarely reduced), usually with more flattened lobes, notosetae compound falcigers and/or spinigers (rarely notosetae absent). They have two prostomial antennae (absent in Micronereis). Their pharynx, when everted, clearly consists of two portions, with a pair of strong jaws on the distal portion and usually with conical teeth on one or more areas of both portions. Most genera have no gills (if present, they are usually branched and arise on mid-anterior segments of body). The larval body consists of four segments.
Ragworms' teeth are made of a very tough, yet lightweight material. Unlike bone and tooth enamel, this is not mineralised with calcium, but is formed by a histidine rich protein, with bound zinc ions. [1] Research on this material could lead to applications in engineering. [2]
Nereididae are currently considered a monophyletic taxon. Their closest neighbours in polychaete phylogenetic tree are Chrysopetalidae and Hesionidae (the superfamily Nereidoidea).
Nereididae are divided into 42 genera, but the relationships between them are as yet unclear. The family contains traditionally three subfamilies - Namanereidinae, Gymnonereinae and Nereidinae.
Subfamily Gymnonereidinae Banse, 1977 [3]
Subfamily Namanereidinae Hartman, 1959 [3]
Subfamily Nereidinae Blainville, 1818 [3]
Subfamily Nereididae incertae sedis: [3]
Ragworms are predominantly marine organisms that may occasionally swim upstream to rivers and even climb to land (for example Lycastopsis catarractarum ). They are commonly found in all water depths, foraging in seaweeds, hiding under rocks or burrowing in sand or mud. Ragworms are mainly omnivorous but many are active carnivores. Nereids breed only once before dying (semelparity), and most of them morph into a distinct form to breed (epitoky).
Ragworms are important food sources for a number of shore birds. [4]
Ragworms such as Hediste diversicolor are commonly used as bait in sea angling. [5] They are a popular bait for all types of wrasse and pollock. They are also used as fish feed in aquaculture. [6]
Ragworms, such as Tylorrhynchus heterochetus , are considered a delicacy in Vietnam where they are used in the dish chả rươi. [7]
In rice-growing areas of China, these worms are called 禾虫 (Mandarin: hé chóng, Cantonese: woh4 chuhng4). They are harvested from the rice fields and are often cooked with eggs.
The genus Glycera is a group of polychaetes commonly known as bloodworms. They are typically found on the bottom of shallow marine waters, and some species can grow up to 35 cm (14 in) in length.
Nereis is a genus of polychaete worms in the family Nereididae. It comprises many species, most of which are marine. Nereis possess setae and parapodia for locomotion and gas exchange. They may have two types of setae, which are found on the parapodia. Acicular setae provide support. Locomotor setae are for crawling, and are the bristles that are visible on the exterior of the Polychaeta. They are cylindrical in shape, found not only in sandy areas, and they are adapted to burrow. They often cling to seagrass (posidonia) or other grass on rocks and sometimes gather in large groups.
The Terebellidae is a marine family of polychaete worms, of which the type taxon is Terebella, described by Carl Linnaeus in his 1767 12th edition of Systema Naturae.
Harmothoe is a genus of marine Polychaete worms belonging to the family Polynoidae. Species of Harmothoe are found world-wide to depths of at least 5,000 m but are more common in shallower water.
Ampharetinae are a subfamily of terebellid "bristle worm". They are the largest subfamily of the Ampharetidae, of which they contain the great majority of the described genera.
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.
Phyllodoce is a genus of polychaete worms, which contains about 200 species. The prostomium bears eyes, two pairs of antennae and a pair of large retractile nuchal organs. The eversible proboscis is clearly divided into two parts.
Phyllodocida is an order of polychaete worms in the subclass Aciculata. These worms are mostly marine, though some are found in brackish water. Most are active benthic creatures, moving over the surface or burrowing in sediments, or living in cracks and crevices in bedrock. A few construct tubes in which they live and some are pelagic, swimming through the water column. There are estimated to be more than 4,600 accepted species in the order.
Cirratulidae is a family of marine polychaete worms. Members of the family are found worldwide, mostly living in mud or rock crevices. Most are deposit feeders, but some graze on algae or are suspension feeders. Although subject to multiple revisions over time, cirratulids are among the few polychaete clades with a verified fossil record.
Orbiniidae is a family of polychaete worms. Orbiniids are mostly unselective deposit feeders on marine detritus. They can be found from the neritic zone to abyssal depths.
The Onuphidae are a family of polychaete worms.
Pilargidae is a family of polychaetes. These marine worms are cylindrical, somewhat flattened, and can be ribbon-like. They can be found free-living on sediment, or shallowly in sediment. Some species within the genera Hermundura and Litocorsa are known to burrow, having reduced heads and parapodia. Two species are known to be commensal with other polychaetes. Pilargis berkeleyae will live in the tubes of Chaetopteridae, and Ancistrosyllis commensalis will live in Capitellidae burrows. Pilargid worms are almost all exclusively predators, classified as carnivore omnivores. They are similar in appearance to Hesionidae, with a peristomium often with two pairs of tentacular cirri, reduced or absent notopodia, and a lack of pharyngeal jaws. The first few segments bearing setigers are also somewhat fused. They can have 0 to 3 antennae, and palps. These polychaetes are rarely the most abundant polychaete.
Hediste diversicolor, commonly known as a ragworm, is a polychaete worm in the family Nereididae. It lives in a burrow in the sand or mud of beaches and estuaries in intertidal zones in the north Atlantic. This species is used in research, but its classification is in dispute; in the literature, it is often classified as Nereis diversicolor. Its specific name "diversicolor" refers to the fact that its colour changes from brown to green as the breeding season approaches.
Phyllodocidae is a family of polychaete worms. Worms in this family live on the seabed and may burrow under the sediment.
Lepidasthenia is a genus of marine Polychaete worms belonging to the family Polynoidae. Species of Lepidasthenia are found worldwide to depths of about 1200 m but are more common in shallower water.
Eunoe is a genus of marine annelids in the family Polynoidae. The genus includes 48 species which are found world-wide, mostly from depths of 50 m or more.
Bylgides is a genus of marine annelids in the family Polynoidae. The genus contains 9 species, all found in the Northern Hemisphere and from shallow inshore waters to depths of about 5000 m.
Gattyana is a genus of marine annelids in the family Polynoidae. The genus includes 11 species, 9 of which occur in the northern hemisphere, the remaining two are from the Indian Ocean off Mozambique and the Southern Ocean off New Zealand. Species of Gattyana are known from shallow water down to depths of about 1200 m.
Sigalionidae is a family of polychaetes belonging to the order Phyllodocida.
Maldanidae is a family of more than 200 species of marine polychaetes commonly known as bamboo worms or maldanid worms. They belong to the order Capitellida, in the phylum Annelida. They are most closely related to family Arenicolidae, and together form the clade Maldanomorpha.
