Cirratulidae
Encyclopedia
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
.
. 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.
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.
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.
There is considerable confusion as to the phylogenetic relationships
in the family and Blake suggests that many species
with global distributions will be found to represent species complex
es within which some species are presently undescribed.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of marine polychaete
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
worms. Members of the family are found worldwide, mostly living in mud or rock crevices. Most are deposit feeders
Detritivore
Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...
, but some graze on algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
or are suspension feeders
Filter feeder
Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
.
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 antennaeAntenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
. 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.
When alive, the body, branchiae and tentacular filaments are often red, orange or yellow, though species of Dodecaceria are dark green or black. Terebellidae
Terebellidae
Terebellidae is a family of polychaete worms. They are surface deposit feeders, catching falling particles with numerous elongate prostomial tentacles splayed out on the sea floor. These tentacles, which are the most or only normally visible portion of the animal and are reminiscent of spaghetti,...
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.
Taxonomy
The generaGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
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.
There is considerable confusion as to the phylogenetic relationships
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
in the family and Blake suggests that many species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
with global distributions will be found to represent species complex
Species complex
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...
es within which some species are presently undescribed.
Genera
- Ambo
- Aphelochaeta Blake, 1991
- Archidice
- Caulleriella Chamberlin, 1919
- Chaetozone Malmgren, 1867
- Cirratulispio
- Cirratulus Lamarck, 1801
- Cirrhatula
- Cirrhatulus
- Cirriformia Hartman, 1936
- 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)