Acrocirridae
| Acrocirridae | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Acrocirridae | ||||||||||||
| Banse , 1969 |
Acrocirridae is the name of a family of mostly small polychaeta (polychaeta), which live freely in soft sediments and which can be found in oceans worldwide as detritus eaters .
features
The Acrocirridae are thread-like or maggot-like and reach lengths of less than 1 cm to about 7 cm, whereby the species of the genus Acrocirrus are significantly larger than those of the genus Macrochaeta . The head, which consists of the prostomium and the peristomium , which is often referred to as the first segment, usually carries a pair of palps , eye spots , nuchal organs and also the first pair of gills , but no antennae. In Macrochaeta, the prostomium is clearly set off and rounded, while in Acrocirrus it forms a narrow keel between the first segments.
The body is clearly segmented , but without a clear division into thorax and abdomen. The parapodia are completely absent from the first segment and the bristles sit directly on the body wall. On the remaining segments, the two branches of the parapodia are uniformly formed as short, truncated cones, with the notopodia in some species being larger than the neuropodia in some segments. Dorsal and ventral cirrus are absent. From the 2nd to the 5th segment there are four pairs of simple gills on each segment. The epidermal papillae resemble those of the Flabelligeridae .
The pharynx sits ventrally and does not have any jaws or teeth. The intestine is a simple straight tube and lacks a throat membrane. The closed blood vessel system has a central heart . The nephridia are formed as metanephridia, with the first pair serving as kidneys and the gametes being released via the following pairs . The bristles on the notopodia are articulated and prickly, while the neuropodia are composed of crescent-bearing bristles with hoods. The joints of the large composite bristles have superficial grooves or folds. Aciculae are absent.
The development cycle has not yet been studied in any Acrocirridae.
distribution and habitat
The Acrocirridae occur in seas worldwide from the tropics to the Antarctic and from the intertidal zone to depths of the sea of 5000 m. They live in soft sediments, with species of the intertidal zone also staying under stones.
nutrition
As far as is known, the Acrocirridae feed on the substrate , swallowing the sediment with the help of their pharynx , digesting the organic components and excreting the mineral components unchanged.
Genera and species
The species of the Acrocirridae family are divided into 9 genera :
- Acrocirrus Pit, 1873
- Chauvinelia Laubier, 1974
- Flabelligella Hartman, 1965
- Flabelligena Gillet, 2001
- Flabelliseta Hartman, 1978
- Helmetophorus Hartman, 1978
- Macrochaeta Pit, 1850
- Swima Osborn, Haddock, Pleijel, Madin & Rouse, 2009
- Teuthidodrilus Osborn, Madin & Rouse, 2011
literature
- Karl A. Banse (1969): Acrocirridae n. Fam. (Polychaeta Sedentaria). Journal of the Fish Research Board of Canada 26, pp. 2595-2620.
- Stanley J. Edmonds: Fauna of Australia, Volume 4A. Polychaetes & Allies. The Southern Synthesis 4. Commonwealth of Australia, 2000. Class Polychaeta. Pp. 272-274, Family Acrocirridae.
Individual evidence
- ↑ Acrocirridae Banse, 1969. WoRMS , 2018. Retrieved October 7, 2018.