Rhodopidae

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Rhodopidae
Helminthope psammobionta, illustration

Helminthope psammobionta , illustration

Systematics
Subclass : Orthogastropoda
Superordinate : Heterobranchia
Order : Hind gill snails (Opisthobranchia)
Subordination : Nudibranchia (Nudibranchia)
Superfamily : Anadoridoidea
Family : Rhodopidae
Scientific name
Rhodopidae
v. Ihering , 1876

The Rhodopidae are a family of worm-like snails that are believed to belong to the nudibranchs (Nudibranchia). These snails were initially counted among the vortex worms (Turbellaria) due to their worm-like habit .

features

The body is elongated and flattened; the length is stretched about 1.5 mm (with Rhodope roskoi ) to about 6 mm ( Rhodope veranii ). However, the animals can contract very severely if disturbed. The head region is somewhat set off and narrowed slightly in relation to the body. The otherwise mollusc-typical stepped foot is completely missing. At the back of the body there is an attachment gland. The jaw, radula, gill and a heart are also missing. The eyes are embedded deep in the head area; paired statocysts are also present . Elongated, slightly curved spicules with blunt ends are embedded in the body . They measure between 70 and 170 μm in length. The length, however, differs from species to species, as does the curvature. The basic color of the body is light yellow to white with orange-red belts, circles or vertical stripes. The color samples are typical of the species.

Way of life and occurrence

Very little is known about the way these animals live. The few live observations and finds come from e.g. Sometimes from tropical aquariums where the animals were accidentally introduced. The origin of such animals can no longer be determined. The animals live in the interstitial of sand and gravel soils, mussel shill , or in dark areas of the phytal in shallow to tidal areas from temperate to tropical seas. The genus is distributed worldwide. R. veranii eats sponge larvae . In contrast to vortex worms, their locomotion is described as slow.

Systematics

The systematic position of the very small family Rhodopidae between strudelworms and mollusks was hotly disputed for over 100 years. Today at least the affiliation to the snails is assured, even if the position within the snails remains somewhat uncertain. In the more recent studies a relationship with the family Dorididae of the nudibranch (Nudibranchia) is favored. Boucot and Rocroi (2005) leave open the superfamily within the nudibranch, McDonald places the family in the superfamily Anadoridoidea Odhner, 1968. Currently only three genera with a total of six species are known. One way to date to the genus Rhodope is submitted shall be of Haszprunar and Hess from the kind Rhodope but assigned no other genus excluded.

Individual evidence

  1. ^ Nudibranch Systematic Index by Gary R. McDonald, p. 67

literature

  • Alfred Kästner : Textbook of special zoology. Volume I: Part 3: Mollusca, Sipunculida, Echiurida, Annelida, Onychophora, Tardigrada, Pentastomida. 5th edition, 608 pages, Gustav Fischer Verlag, Jena 1993, ISBN 3-334-60412-8
  • Gerhard Haszprunar and Martin Heß: A new Rhodope from the Roskoff area (Bretagne), with a review of Rhodope species. Spixiana, 28: (3): 193-197, Munich 2005 ISSN  0341-8391
  • Philippe Bouchet, Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN  0076-2997

Web links

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