Magelona mirabilis

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Magelona mirabilis
Systematics
Class : Polychaete (Polychaeta)
Subclass : Palpata
Order : Canalipalpata
Subordination : Spionida
Genre : Magelona
Type : Magelona mirabilis
Scientific name
Magelona mirabilis
( Johnston , 1865)

Magelona mirabilis is a grave forming in the sediment of detritus living polychaete (Polychaeta) from the family Magelonidae that in the northeastern Atlantic Ocean is widespread.

features

Magelona mirabilis has a cylindrical body up to 17 cm long with around 150 segments and a constriction on the 9th segment. The prostomium is longer than it is wide and has no horn-like extensions in front. Each of the two long palps is covered with two longitudinal rows of papillae. The parapodia on the segments of the thorax are dorsally covered with pointed to broadly rounded, oval or triangular lamellae behind the bristles and ventrally with somewhat smaller cirrus, also with small dorsal and somewhat longer ventral cirrus and winged capillary-like bristles. The parapodia of the 9th segment each have a bundle of bristles that are widened subdistally, dorsally and ventrally. On the parapodia of the abdomen behind the bristles there are short lamellae, finger-like lamellae between the branches, dorsally and ventrally small papillae-shaped lamellae and three-toothed hooks with a hood. The thorax is pale pink, the abdomen dark gray or greenish, laterally with pale spots.

Distribution, habitat and way of life

Magelona mirabilis is distributed in the northeastern Atlantic Ocean , the Mediterranean Sea , the Adriatic Sea , the Black Sea , the English Channel , the entire North Sea and as far as the Bay of Kiel . It lives in self-dug tunnels in sand and mud from the intertidal zone to a depth of 60 m. Like other Magelonidae, it grazes the organic coating of detritus from the sediment surface with the help of its papillary palps.

Development cycle

Magelona mirabilis is single sex, but little is known about its reproductive behavior. Animals ready to mate were observed on the Scottish coast in March and in France in May. The fertilization takes place in the open sea water, and the development proceeds via a freely swimming larva as zooplankton , which sinks after several weeks and metamorphoses into a creeping worm . The species is considered an r-strategist , which develops rapidly, lays many eggs and lives briefly.

Systematics

The species was first found in Scottish waters by George Johnston in 1865 and first described as Mæa mirabilis (later also Maea mirabilis ). For a long time, all Magelona in the North Sea were assigned to the species Magelona papillicornis , which, however, was first described in Brazil and to which the European animals do not belong. The European Magelona were later assigned to the species described by Johnston under the updated name Magelona mirabilis , but it was found that there were two or even more species and Johnston's description was not clear enough to assign them. Dieter Fiege, Frank Licher and Andrew SY Mackie re-described Magelona mirabilis with a neotype and also described a second European species, Magelona johnstoni .

literature

Web links