Thecoscyphus zibrowii

Thecoscyphus zibrowii
Systematics
Trunk :	Cnidarians (Cnidaria)
Class :	Umbrella jellyfish (Scyphozoa)
Order :	Crown jellyfish (Coronatae)
Family :	Nausithoidae
Genre :	Thecoscyphus
Type :	Thecoscyphus zibrowii
Scientific name
	Thecoscyphus zibrowii
	Werner , 1984

Thecoscyphus zibrowii is a species from the class of umbrella jellyfish (Scyphozoa) within the cnidarians (Cnidaria). Thecoscyphus zibrowii does not have a medusa stage and only occurs as a polyp .

Naming

The species epithet was chosen by the author of the first description , the German marine biologist Bernhard Werner (1910–1984), in honor of Helmut W. Zibrowius (* 1941), who carried out the sampling freediving with the aid of an autonomous light diving device.

features

Thecoscyphus zibrowii has reduced the medusa stage and reproduces in the polyp stage. The Nausithoidae family , to which Thecoscyphus belongs, is characterized by the fact that the polyps form a slender peridermal tube made of chitin , into which they can withdraw. Such polyps are called Stephanoscyphistomae after Gerhard Jarms (* 1948/49?).

The polyps of Thecoscyphus zibrowii can be divided into three areas: the tentacle wreath, collar and the lower soft body area, which is always located in the tube. The polyps of this species have relatively few, rarely more than 20 tentacles, compared to other species in the family. These are stretched horizontally to the side and, when fully extended, usually bent downwards like an umbrella. The tip of the tentacle, which appears buttoned by the accumulation of nettle cells, often touches the ground. The tentacles are thickened at their base and merge into the collar. The measurements showed that z. B. an adult polyp with 15 tentacles has an upper tube diameter of around 1.41 mm and a tentacle base width of around 280 μm. In the extended state, the tentacles have a diameter of approximately 120 μm in the area of the cnidocytes arranged in spirals and of approximately 80 μm in the area between the cnidocytes.

If one looks at the collar of the polyp from above, it can be seen that it is divided into a peripheral, tentacle-bearing and a central, lower-lying area. The central area consists of a flat mouth disc which is drawn out perradially to form triangular lobes, which pull up on the inner wall of the peripheral collar area. The extensions of the septa can be seen as thin white lines through the mouth disc. In the center of the mouth disc there is a mouth opening that can be widened to the peripheral collar area. In the side view, it can be seen that the collar is slightly stronger in the lower area and forms a pronounced ring. When stretched out, this lies like a small bead directly on the upper tube opening. The tube formation zone is located directly below this bead. When the tentacles are completely collapsed, this area detaches from the tube wall and then appears as a brownish ring at times.

Directly below the collar, the soft body is relatively easy to see through the transparent tube in this area. The septa (septa in the gastric space ) are only formed as narrow ridges in the upper part of the soft body of the polyp, which protrude further down into the gastric space. The upper part of the peridermal tube of the adult polyps has a light, transparent amber color, which becomes darker towards the foot and changes to a dark brown, opaque color in older polyps. The periderm of very young polyps is initially colorless and transparent and only becomes more yellow and opaque with age. The outside of the periderm tube is provided with prominent (decisive) ring and weakly developed longitudinal structures. The tube is lengthened in the area of the tube formation zone. The inner wall of the tube is poor in structure as there are no peridermal teeth. In the lower tube area, however, there are regularly arched periderm strips that shine through in a fish-scale-like arrangement. The diameter of the tube increases sharply directly above the foot disk, the increase in diameter is smaller further up. For the description of the tubular shape of older polyps, the following measurements and measured values resulted from measurements: diameter of the foot disk , diameter of the tube directly above the foot disk, shape quotient of the 2 mm length and shape quotient of the 5 mm length (weighted arithmetic mean ). ${\ displaystyle D_ {Sch} = 0 {,} 417 \, \ mathrm {mm}}$ ${\ displaystyle D_ {unt} = 0 {,} 237 \, \ mathrm {mm}}$ ${\ displaystyle D / L_ {2 \, \ mathrm {mm}} = 0 {,} 370}$ ${\ displaystyle D / L_ {5 \, \ mathrm {mm}} = 0 {,} 244}$ ${\ displaystyle \! \ n = 44}$

Thecoscyphus zibrowii is characterized both by having a periderm tube and by the soft body organization as a typical coronary polyp. Due to its structural features, it can be assigned to this family. However, the shape quotients of the tube dimensions are significantly higher and the tentacle numbers are significantly lower than in all other known Stephanoscyphistomae, which is why the new genus Thecoscyphus introduced by Werner in 1984 is justified. When sexually mature, the Nausithoidae usually have eight gonads .

Geographical distribution and occurrence

B. Werner found the first specimens of Thecoscyphus zibrowii in 1975 in growth samples from submarine (= submarine / undersea) caves on the coast of the Sorrento peninsula in the Gulf of Naples . So far, the species has only been found one more time in submarine caves on the coast of Lebanon . The animals used for the studies of this species go back to the individuals collected by H. Zibrowius in 1975. In 1983 Werner characterized the caves from which the polyps originate as closed sac caves ; only two of the caves have an air dome or multiple entrances. They are located in the limestone coast i. d. Usually between 5 and 15 m water depth and extend about 30 to 100 m into the rock. Mostly they can be assigned to the still water zone, only the two open caves have stronger currents.

literature

Ilka Sötje: Studies on the reduced metagenesis of Thecoscyphus zibrowii Werner , 1984 (Cnidaria, Scyphozoa) . Inaugural dissertation, University of Hamburg , 2003.

Web links

Photography , University of Hamburg
Protocol Porifera / Cnidaria (PDF file; 96 kB), Till Biskup
Localization of digestion activities in polyps of Nausithoe planulophora and Thecoscyphus zibrowii (Coronatae, Scyphozoa, Cnidaria) , Springerlink ( Helgoländer Meeresuntersuchungen , 51, 1997. pp. 477-485)

Individual evidence

↑ G. Jarms, U. Båmstedt, H. Tiemann, M. B. Martinussen, J. H. Fosså: The holopelagic life cycle of the deep-sea medusa Periphylla periphylla (Scyphozoa, Coronatae) . Sarsia, 1999. 84, pp. 55-65
↑ ^a ^b I. Sötje, G. Jarms: Detailed description of Thecoscyphus zibrowii Werner, 1984 (scyphozoa Coronatae) with remarks on the life cycle . Mitt. Hamb. zool. Mus. Inst., 1999. 96, pp. 5-13
↑ B. Werner; H.-E. Gruner (Ed.): Cnidaria . P. 305. In: Textbook of special zoology . Volume 1: Invertebrates - Part 2: Cnidaria, Ctenophora, Mesozoa, Plathelmithes, Nemertini, Entoprocta, Nemathelminthes, Priapulida . Fischer, Jena 1984
↑ E. Haeckel: The system of the Medusen. First part of a monograph on Medusa . Memoranda of the Medicinisch-Naturwissenschaftlichen Gesellschaft, 1879. pp. 1–657
↑ G. Jarms (verbal information) / Ilka Sötje (* 1965)

[1] G. Jarms, U. Båmstedt, H. Tiemann, M. B. Martinussen, J. H. Fosså: The holopelagic life cycle of the deep-sea medusa Periphylla periphylla (Scyphozoa, Coronatae) . Sarsia, 1999. 84, pp. 55-65

[Sötje/Jarms,_1999-2] I. Sötje, G. Jarms: Detailed description of Thecoscyphus zibrowii Werner, 1984 (scyphozoa Coronatae) with remarks on the life cycle . Mitt. Hamb. zool. Mus. Inst., 1999. 96, pp. 5-13

[3] B. Werner; H.-E. Gruner (Ed.): Cnidaria . P. 305. In: Textbook of special zoology . Volume 1: Invertebrates - Part 2: Cnidaria, Ctenophora, Mesozoa, Plathelmithes, Nemertini, Entoprocta, Nemathelminthes, Priapulida . Fischer, Jena 1984

[4] E. Haeckel: The system of the Medusen. First part of a monograph on Medusa . Memoranda of the Medicinisch-Naturwissenschaftlichen Gesellschaft, 1879. pp. 1–657

[5] G. Jarms (verbal information) / Ilka Sötje (* 1965)