The Serpulidae are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of sessile, tube-building

annelid The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to vario ...

worms in the class Polychaeta. The members of this family differ from other sabellid tube worms in that they have a specialized operculum that blocks the entrance of their tubes when they withdraw into the tubes. In addition, serpulids secrete tubes of

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

. Serpulids are the most important biomineralizers among annelids. About 300 species in the family Serpulidae are known, all but one of which live in saline waters. The earliest serpulids are known from the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

( Wordian to late Permian), and possibly the upper Permian south

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

The blood of most species of serpulid and sabellid worms contains the oxygen-binding pigment chlorocruorin. This is used to transport oxygen to the tissues. It has an affinity for

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

which is 570 times as strong as that of the haemoglobin found in human blood. Empty serpulid shells can sometimes be confused with the shells of a family of marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

s, the Vermetidae or worm snails. The most obvious difference is that serpulid shells are dull inside, whereas the molluscan vermetid shells are shiny inside.

Selected genera

*'' Amplicaria'' Knight-Jones, 1984 *'' Anomalorbis'' Vine, 1972 *'' Apomatus'' Philippi, 1844 *'' Bathyvermilia'' Zibrowius, 1973 *'' Bushiella'' Knight-Jones, 1973 *'' Capeospira'' Pillai, 1970 *'' Chitinopoma'' Levinsen, 1884 *'' Circeis'' Saint-Joseph, 1894 *'' Crucigera'' Benedict, 1887 *'' Dextralia'' Knight-Jones, 1973 *'' Ditrupa'' Berkeley, 1835 *'' Eulaeospira'' Pillai, 1970 *'' Ficopomatus'' Sauthern, 1921 *'' Filograna'' Berkeley, 1835 *'' Filogranella'' Ben-Eliahu and Dafni, 1979 *'' Filogranula'' Langerhans, 1884 *'' Galeolaria'' Lamarck, J.B. de (1818) *'' Hyalopotamus'' Marenzeller, 1878 *'' Hydroides'' Gunnerus, 1768 *'' Janua'' Saint-Joseph, 1894 *'' Josephella'' Caullery and Mesnil, 1896 *'' Leodora'' Saint-Joseph, 1894 *'' Marifugia'' Absolon & Hrabe, 1930 *'' Metavermilia'' Bush, 1904 *'' Neodexiospira'' Pillai, 1970 *'' Neovermila'' Day, 1961 *'' Nidificaria'' *'' Paradexiospira'' Caullery and Mesnil, 1897 *'' Paralaeospira'' Caullery and Mesnil, 1897 *'' Pileolaria'' Claparede, 1870 *'' Placostegus'' Philippi, 1844 *'' Pomatoceros'' Philippi, 1844 *'' Pomatoleios'' Pixell, 1912 *'' Pomatostegus'' Schmarda, 1861 *'' Protolaeospira'' Pixell, 1912 *'' Protula'' Risso, 1826 *'' Pseudochitinopoma'' Zibrowius, 1969 *'' Pseudovermilia'' Bush, 1907 *†'' Rotularia'' Defrance, 1827 *'' Salmacina'' Claparede, 1870 *'' Semivermila'' Imajima, 1978 *'' Serpula'' Linnaeus, 1767

Type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

*'' Simplicaria'' Knight-Jones, 1973 *'' Spirobranchus'' Blainville, 1818 *'' Spirorbis'' Daudin, 1800 *'' Turbocavus'' Prentiss et al., 2014 *'' Vermiliopsis Saint-Joseph, 1894 *'' Vinearia'' Image:Ficopomatus enigmaticus individual and tubes.jpg, '' Ficopomatus enigmaticus'' Image:Filograna implexa.jpg, '' Filograna implexa'' Image:Red fanworm1.jpg, '' Protula bispiralis'' Image:Serpula vermicularis 2.jpg, '' Serpula vermicularis'' Image:Christmas tree worms.jpg, '' Spirobranchus giganteus'' Image:Spirorbe.jpg, '' Spirorbis sp.''

References

;Citations ;General * * * Annelid families Extant Permian first appearances Taxa named by Constantine Samuel Rafinesque {{annelid-stub