Aciculata
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| Scientific name | ||||||||||||
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| Rouse & Fauchald 1997 |
Aciculata is the name of an order usually predatory or necrophagous , Wild polychaete (Polychaeta) in the subclass Palpata , which are found in oceans worldwide. In terms of their size, they correspond to the order Errantia (Audouin & H. Milne Edwards, 1832), which is therefore regarded as a synonym , and comprise almost half of all families of the Polychaeta.
features
Characteristic of the aciculata are, as the name of the taxon already suggests, parapodia suitable for locomotion , in which aciculae are embedded, modified bristles that attach to this and several muscles as an inner skeleton . The aciculata have lobed parapodia with a dorsal notopodium and a ventral neuropodium. In each of these four branches there is at least one acicula, which generally remains in the bristle follicle and does not grow outward. In addition, the aciculata have composite bristles, the two limbs of which are connected by a joint. At the notopodia there are dorsal cirrus, at the neuropodia there are ventral cirrus. On the prostomium there are three rostroventrally oriented antennas - a central antenna and two side antennas - into which nerves lead from the front part of the brain. However, the number of antennas can be reduced; in the genus Nereis , for example, there are only two side antennas and no central antenna.
The name of the traditional taxon Errantia, which corresponds to the Aciculata, refers to the great mobility and the non-localized life of these many bristles. The sedentaria that are contrasted with these and live in tied-up condominiums are not, however, a monophyletic group.
Distribution, habitat and way of life
Aciculata are common in oceans worldwide on both soft and hard substrates. They move actively, run, swim, crawl, drill their way through the substrate or crawl into crevices in the rock. Some species build living tubes, which they leave to forage.
Most Aciulata are either scavengers or predators who prey on crabs , clams , hydroids , sponges or polychaetes with their powerful mandibles . Some species are commensals on sponges, cnidarians , echinoderms , crabs or polychaetes. In rare cases there are also parasites on other polychaetes (family Arabellidae ).
Systematics
According to the Rouse & Fauchald system of 1998 , the order Aciculata and its sister group , the Canalipalpata , form the subclass Palpata .
According to this system, the order Aciculata includes the suborders Phyllodocida and Eunicida with the following families :
literature
- Stanley J. Edmonds: Fauna of Australia, Volume 4A. Polychaetes & Allies. The Southern Synthesis 4. Commonwealth of Australia, 2000. Class Polychaeta. Pp. 120f., Aciculata.
- Gregory W. Rouse, Kristian Fauchald (1998): Recent views on the status, delineation, and classification of the Annelida. (PDF). American Zoologist. 38 (6), pp. 953-964. doi: 10.1093 / icb / 38.6.953
- Peter Ax: The system of Metazoa II. A textbook on phylogenetic systematics. Gustav Fischer Verlag, Stuttgart / Jena 1999. pp. 47–56, chapter Polychaeta : Aciculata - Canalipalpata , p. 52.
Web links
- Fredrik Pleijel, Gregory W. Rouse: Aciculata. In: The Tree of Life Web Project, 2004.