Cirratulidae is 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 marine polychaete worms. Members of the family are found worldwide, mostly living in mud or rock crevices.Marine Species Identification Portal
/ref> Most are deposit feeders, but some graze on

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

or are suspension feeders. Although subject to multiple revisions over time, cirratulids are among the few polychaete clades with a verified

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

Description

Cirratulids vary in size from one to twenty centimetres long. They are mostly burrowers in soft sediments but some live in rock crevices. The head is conical or wedge-shaped and has no antennae. The body is generally cylindrical, tapering at both ends. Cirratulids are characterised by a large number of simple elongate filaments along the body. Some of these occur as an anterior cluster of tentacles, grooved for deposit-feeding, but the majority, the branchiae, are found one pair per segment, and do not have grooves. The chaetae (bristles) are simple capillaries, usually with hooks, and emerge directly from the body wall. There are no anal cirri (slender sensory appendages). The worm is usually buried with only the writhing branchial filaments visible. Some cirratulids can build tubes of calcium carbonate. A study by Guido et al. (2024) reported cirratulid aggregates as the first known example in the animal kingdom of the so called double-phased biomineralization process. When alive, the body, branchiae and tentacular filaments are often red, orange or yellow, though species of ''Dodecaceria'' are dark green or black. Terebellidae and other worm families may superficially look similar to cirratulids with a mass of filaments. However, in terebellids, the filaments arise from the mouth or are restricted to the anterior three segments, whereas cirratulid branchiae occur throughout the body, one pair per segment.Polychaetes:Cirratulidae

Taxonomy

The

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

are poorly defined and Blake undertook a partial revision in 1996. He divided them into three groups, the multi-tentaculate genera such as ''Cirratulus'' and ''Cirriformia'', the bi-tentaculate soft-substrate genera such as ''Caulleriella'', ''Chaetozone'', ''Tharyx'' and the bi-tentaculate hard substrate genera such as ''Dodecaceria''.Blake, J.A. (1996). Family Cirratulidae Ryckholdt, 1851. pp. 263-384 in Blake, J.A., Hilbig, B. & Scott, P.H. (eds) The Annelida. Part 3 Polychaeta: Orbiniidae to Cossuridae. Vol. 6. Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and western Santa Barbara Channel. Santa Barbara Museum of Natural History : Santa Barbara, California There is considerable confusion as to the phylogenetic relationships in the family and Blake suggests that many

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

with global distributions will be found to represent

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

es within which some species are presently undescribed.

Fossil record

The earliest cirratulid on record, ''Dodecaceria cretacea'' (Voigt, 1971), later reclassified as the ichnofossil ''Caulostrepsis cretacea'', was responsible for leaving boring traces on Late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

coral reefs. There's no known

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

record, but from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

onwards, reports of cirratulid bioconstructions in South Africa and the Americas are relatively frequent. Two species within '' Diplochaetetes'', ''D. longitubus'' (Weissermel, 1913) and ''D. longitubus vermicularis'' (Weissermel, 1926), are known from Namibian sites. The species ''D. mexicanus'' (Wilson, 1986) was reported in

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

fossiliferous sites across multiple locations in the pacific coasts of the Americas, from

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

. Recent cirratulid bioconstructions found in the same areas are attributed to the genus '' Dodecaceria''. Several authors, such as Reish (1952), Fischer et al. (1989, 2000) and Guido et al. (2024) have reported many similarities between ''Dodecaceria'' and ''Diplochaetetes'' bioconstructions, but whether the two genera should be considered

synonyms A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

or not remains unresolved.

Genera

* '' Ambo'' * '' Aphelochaeta'' Blake, 1991 * '' Caulleriella'' Chamberlin, 1919 * '' Chaetozone'' Malmgren, 1867 * '' Cirratulispio'' * '' Cirratulus'' Lamarck, 1801 * '' Cirrhatula'' * '' Cirrhatulus'' * '' Cirriformia'' Hartman, 1936 * '' Diplochaetetes'' † Weissermel, 1913 * '' Dodecaceria'' Örsted, 1843 * '' Heterocirrus'' Grube, 1855 * '' Labranda'' * '' Monticellina'' Laubier, 1961 * '' Naraganseta'' * '' Pentacirrus'' * '' Promenia'' * '' Protocirrineris'' Czerniavsky, 1881 * '' Pseudocirratulus'' * '' Tharyx'' Webster & Benedict, 1887 * '' Timarete'' Kinberg, 1866 * '' Audouina'' Hartman, 1936 * '' Audouinia'' Quatrefages, 1865 * '' Cirrineris'' misspelling of ''Cirrhineris'' Blainville, 1828 * '' Cirrhineris'' Blainville, 1828 (nomen dubium)

References

{{Authority control Terebellida Annelid families