Buoy-forming barnacles

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Buoy-forming barnacles
Washed-up specimen with its buoy (left in the picture, consisting of a small piece of wood and the whitish foam raft)

Washed-up specimen with its buoy (left in the picture, consisting of a small piece of wood and the whitish foam raft)

Systematics
Superordinate : Thoracica
Order : Barnacles (Pedunculata)
Subordination : Lepadomorpha
Family : Lepadidae
Genre : Dosima
Type : Buoy-forming barnacles
Scientific name
Dosima fascicularis
( J.Ellis and Sol. , 1786)

The buoy-forming barnacle ( Dosima fascicularis ) is - besides Dosima guanamuthui ( Daniel 1971) - the only species of the genus Dosima and belongs to the order of barnacles . It is considered to be the most specialized barnacle in the Pleuston .

history

A first documentation of a find on the beach in Norway in 1767 comes from Peter Ascanius . The first description of the species comes from John Ellis and Daniel Solander and was published in 1786 (both posthumously ) as Lepas fascicularis . Charles Darwin assigned the species to the genus Dosima ( Gray 1825) in 1852 .

distribution

Dosima fascicularis is cosmopolitan , but the breeding grounds are in the high seas of the tropics and subtropics , the North Sea seems to be too cold for that. Nevertheless, they have long been found regularly as flotsam in the flushing fringes of the coasts of Northern Europe , also on the coasts of the German North Sea.

According to Nehring and Leuchs (1999), Dosima fascicularis is a “ Neozoon simulatum” for the North Sea , a species that appears new in an area without recognizable human intervention (“natural area expansion”). Minchin (1996), however, suspects that the increased occurrence of tar clumps and plastic waste in the oceans favors the spread of Dosima fascicularis on northern European coasts. Studies on the Irish coast have shown that 63% of the cirripede (crustacea) adheres to lumps of tar - with a diameter of more than 25 mm - and 21% to plastic waste. Presumably through this improved offer, this crustacean was able to expand its habitat.

Way of life

A washed-up specimen of Dosima fascicularis performs filtering movements with its cirrus.

Buoy-forming barnacles belong to the Pleuston or Neuston , the entirety of all living things that live in the top layer of (sea) water. The actively motile larvae ( nauplius larvae ) feed by filtering. After the transformation into the cypris larva, they look for buoyant material as a raft, mostly macroalgae (e.g. Fucus ) or driftwood , very rarely also ship hulls , to which they hold on and undergo their metamorphosis into an adult animal. The then sessile animals adhere firmly to their raft with their handle and use it as a transport vector like a floating buoy . As they grow further, they form a foam-like , gas-filled structure (foam raft) that is itself buoyant. The ability to create such an additional raft distinguishes Dosima from other drifting barnacles such as Lepas anatifera or Lepas anserifera . The specimens of Dosima fascicularis hang individually or in groups on their buoy upside down in the Neuston and filter plankton ( suspension eater ) with their cirrus . The color of the limestone plates ( carapace ) can be between pale yellow and purple-brown. Often there is also a bluish coloration.

swell

Individual evidence

  1. ↑ Lanna Cheng, Ralph A. Lewin: Goose barnacles (Cirripedia: Thoracica) on flotsam beached at La Jolla, California . In: Fishery Bulletin . 74, No. 1, 1974, pp. 212-217.
  2. ^ Dan Minchin: Tar pellets and plastics as attachment surfaces for lepadid cirripedes in the North Atlantic Ocean. In: Marine Pollution Bulletin. 32, 1996, p. 855, doi: 10.1016 / S0025-326X (96) 00045-8 .

Web links

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