Glaucidae

Glaucus atlanticus (left) and Glaucus marginatus (right)

The Glaucidae are a family of thread worm in the subordination of the nudibranchs. It consists of the two pelagic, floating worldwide in warm and temperate seas caseless snail species Glaucus atlanticus and Glaucus marginatus (also Glaucilla marginata ) that feed on the sea living cnidarians.

Features

In adaptation to the pelagic the Glaucidae have a flattened body with 3 to 4 pair of lateral "feet " ( peduncles ), in which the long Cerata sit that stabilize the position of the worm in the water. The animals have a small head with protruding eyes, a pair of short oral sensor and above two very short, barely visible rhinophores. As with other screw thread lead in the Cerata foothills of the midgut gland, which in sg Nettle bags end. Here, the nematocysts of cnidarians are stored and eaten serve the defense of the screw against predators.

The teeth of the row radula have a protruding bump which is comparatively longer than those of Glaucus atlanticus with Glaucus marginatus, and a number of teeth. The powerful jaws are chitinös. The anus opens laterally on the back between the second and third peduncle, the nephridium also on the back between the first and second peduncle.

Like other thread snails are the hermaphrodites Glaucidae. The female genital opening is on the belly right. The reinforced with a Chitinstachel penis is longer than the body of the worm and so allows for a reciprocal mating of two floating worm. The eggs are attached in Eischnüren on floating prey remains or Tang. From the eggs numerous veliger larvae with a small shell, which feed on plankton and eventually metamorphose into small shell-less snails thread.

The Glaucidae eat pelagic Hydrozoa ( sailing and siphonophores, Porpita porpita ). While Glaucus atlanticus reach lengths of 4 cm, Glaucus marginatus only a few millimeters in size.

System

After Bouchet and Rocroi ( 2005), the family Glaucidae one of four families in the superfamily Aeolidioidea. To the family includes two types:

• Glaucus marginatus ( Bergh, 1860), synonym: Glaucilla marginata Bergh, 1860

The two species traditionally associated with the two monotypic genera Glaucus Forster, 1777 and Glaucilla Bergh, in 1860, but put them Valdés and Campillo 2004 due to the great similarity in a common genus Glaucus, so that the Glaucidae are now a mono- generic family.

Based on a work by Michael Miller 1974 for a while, the concept of Glaucidae family by some authors to a much greater extent postulated including subfamilies Facelininae, Favorininae, Crateninae and Herviellinae was understood (previous families Babainidae, Facelinidae and Favorinidae ) and included hereafter as numerous benthic species, including for example Facelina, Dondice and Hermissenda. This proposal has always been controversial and was rejected inter alia on the grounds that the subfamilies are polyphyletic and the two types Glaucus atlanticus and Glaucilla marginata because of their highly specialized pelagic lifestyle of the status of a separate family fees. The temporarily enclosed with under Glaucidae benthic species belong in the scheme of Bouchet and Rocroi (2005) the family Facelinidae.