Cirratulus cirratus
Encyclopedia
Cirratulus cirratus is a species
of marine polycheate worm in the family Cirratulidae
. It occurs in the littoral and sub-littoral zones of the Atlantic Ocean.
Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment
may bear setae (bristles) and parapodia
(paddle-like appendages). Some species live freely, either swimming, crawling or burrowing, and these are known as "errant". Others live permanently in tubes, either calcareous or parchment-like, and these are known as "sedentary".
or head is a blunt cone with a row of 4 to 8 large black eyes on either side. The first segment bears two groups of up to eight feeding tentacles. At intervals along the body there are pairs of long slender gill
s which look like a mass of reddish threads. Short, blunt bristles are found on segments 10 to 12 and more on segments 20 to 23.
, catching particles floating past with its tentacles and conveying them to its mouth.
The sexes are separate and the worms become sexually active spasmodically at intervals of one to two years. The males are white at this time and the females yellowish due to the oocyte
s in their coelom
. Once the oocytes have been fertilised, they are stuck to rocks in a jelly-like mass. They hatch after six days into ciliated post-trochophore larvae. These live off the yolk sac for about twenty-four days before settling and starting filter feeding. Asexual reproduction
by means of clones
growing from the posterior of the worm have been recorded, but the taxonomic status of Cirratulus is under constant review and this report may refer to a different 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...
of marine polycheate worm in the family Cirratulidae
Cirratulidae
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.-Description:...
. It occurs in the littoral and sub-littoral zones of the Atlantic Ocean.
Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment
Segmentation (biology)
Segmentation in biology refers to either a type of gastrointestinal motility or the division of some animal and plant body plans into a series of repetitive segments. This article will focus on the segmentation of animal body plans, specifically using the examples of the phyla Arthropoda,...
may bear setae (bristles) and parapodia
Parapodium
Parapodia , singular parapodium, are paired, un-jointed lateral outgrowths from the bodies of two different invertebrate groups, which are primarily marine in habitat...
(paddle-like appendages). Some species live freely, either swimming, crawling or burrowing, and these are known as "errant". Others live permanently in tubes, either calcareous or parchment-like, and these are known as "sedentary".
Description
C. cirratus grows to up to thirty centimetres long with up to 150 segments. It has a slender, orange, pinkish or brownish body. The prostomiumProstomium
Prostomium is the first body segment in annelid worms. It is in front of the mouth, being usually a small shelf- or lip-like extension over the dorsal side of the mouth. It sometimes bears antennae and eyes. It often functions like a kind of overlip when the animal is feeding...
or head is a blunt cone with a row of 4 to 8 large black eyes on either side. The first segment bears two groups of up to eight feeding tentacles. At intervals along the body there are pairs of long slender gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s which look like a mass of reddish threads. Short, blunt bristles are found on segments 10 to 12 and more on segments 20 to 23.
Distribution and habitat
C. cirratus is found along the coasts of north west Europe and also in the south Atlantic Ocean. It mostly occurs living in burrows on the lower shore in mud or muddy sand, often underneath or between rocks.Biology
C. cirratus is a filter feederFilter 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,...
, catching particles floating past with its tentacles and conveying them to its mouth.
The sexes are separate and the worms become sexually active spasmodically at intervals of one to two years. The males are white at this time and the females yellowish due to the oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...
s in their coelom
Coelom
The coelom is a fluid-filled cavity formed within the mesoderm. Coeloms developed in triploblasts but were subsequently lost in several lineages. Loss of coelom is correlated with reduction in body size...
. Once the oocytes have been fertilised, they are stuck to rocks in a jelly-like mass. They hatch after six days into ciliated post-trochophore larvae. These live off the yolk sac for about twenty-four days before settling and starting filter feeding. Asexual reproduction
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
by means of clones
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
growing from the posterior of the worm have been recorded, but the taxonomic status of Cirratulus is under constant review and this report may refer to a different species.