Stygiomedusa gigantea
Schematic drawing of Stygiomedusa gigantea
Stygiomedusa gigantea (syn. Stygiomedusa fabulosa and Stygiomedusa stauchi ) is a living in the deep sea, very large type of screening Jellyfish ( Scyphozoa ). It is the only species of the genus Stygiomedusa.
Features
The shield of Medusa measures to about 140 cm in diameter. The color varies from purple to tiefbraunrot. The surface is smooth. It owns four mouth tentacles that can be m meters to about 6 [Note 1]. Stomach measures about half of the screen diameter; go of him from 17 to 18 radial channels. In addition, a ring channel is present. In the stomach, there are numerous cirri, about 5 mm long, which are equipped with stinging cells. The animals weigh up to 90 kg. A exumbrellare pit around the central part of the screen marked about the stomach. You have 20 randliche sense organs ( Rhopalia ) and about 60 randliche cloth. The mouth is drawn in a cross shape and a short mouth tube.
The Gonadenporen inter located radially have a diameter of 1.5 cm. The species is viviparous ( viviparous ). The holotype was observed that seated at each of the four gonads more whitish, ovoid body on the wall of the gonad. They varied in size from 1 cm to 5 × 0.5 × 2.5 cm. A somewhat larger body of 7.5 × 5 cm contained an evolving, small jellyfish. Fully developed small medusae just before the detachment had a screen diameter of 10 cm. None of the young and developing medusae had randliche tentacles. The oral arms are well developed, relatively wide and filamentous.
Geographic occurrence and habitat
According to previous sightings and catches Stygiomedusa gigantea is likely to be widespread. They have been found in North and South Atlantic, but also in front of the American Pacific coast. Their habitat is likely to occur after the previous findings in a depth of 1000 m to 1800 m.
Way of life
Relatively little is known about the life of Stygiomedusa gigantea. Judging by the stomach contents to Stygiomedusa gigantea feeds on crustaceans ( Crustacea ), the type Eryoneicus faxoni Bouvier, 1905 (Family Polychelidae ) was found in the stomach contents of a captive specimen.
Probably Stygiomedusa gigantea lives in symbiosis with the species Thalassobathia pelagica ( viscera Fishy, Ophidiiformes ). The fish live around the screen of Stygiomedusa gigantea around. The fish gets effective protection from predators. The medusa benefited by the removal of parasites and by the catching of fish that trace their symbionts.
System
The genus Stygiomedusa was erected in 1959 by Frederick Stratten Russell. The type species was at this time Stygiomedusa fabulosa Russell, 1959. Recent investigations are Stygiomedusa fabulosa Russell 1959, and also Stygiomedusa stauchi Repelin 1967 junior synonyms to Stygiomedusa gigantea ( Browne, 1910).