English jellyfish

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English jellyfish
Stauromeduse from Ernst Haeckel's Kunstformen der Natur, 1904

Stauromeduse from Ernst Haeckel's Kunstformen der Natur, 1904

Systematics
without rank: Holozoa
without rank: Multicellular animals (Metazoa)
without rank: Tissue animals (Eumetazoa)
Trunk : Cnidarians (Cnidaria)
Class : Staurozoa
Order : English jellyfish
Scientific name of the  class
Staurozoa
Marques & Collins , 2004
Scientific name of the  order
Stauromedusae
Haeckel , 1879

The stick jellyfish or cup jellyfish (Stauromedusae, the only order of the Staurozoa since 2006) are sessile or semi- sessile , rarely free-living, solitary , mostly small (around 5 cm) cnidarians (Cnidaria) with a four-rayed body without a skeleton. They live exclusively in the sea on rocky coasts attached to seaweed and algae, but also in the deep sea on hydrothermal vents . They are the only order of the class Staurozoa Marques & Collins, 2004. The order Stauromedusae was previously placed with the umbrella jellyfish (Scyphozoa) before Antonio Marques and Allen Collins recognized their independence in 2004 and set up a new class within the cnidarians. This initially contained the extinct order of Conulatae , which was then removed from the class in 2006.

features

The Stauromedusae show features of both the polyps and the medusa . The body can be divided into a cup-shaped, medusoid upper part and a polypoid stem. The calyx corresponds to the screen in medusa, the inner or upper side of the subumbrella, the outer or lower side of the exumbrella. The jelly is thin but clearly developed. Since the animals do not make swimming movements, the subumbrellare is circular muscle , although usually not (yet) available but regressed. In most species the medusoid upper part is divided octoradially. On the edge of the screen there are buttoned tentacles arranged in 8 groups of 20 - 100 each . The edge between the tufts of tentacles is more or less strongly curved, so that the tentacles stand as if on "arms". There are atric Haplonemen and microbasic heterotrich Euryteles as nettle capsule types. Between the tentacle arms, in the per and inter radii, there are cushion-shaped edge anchors. They have many gland cells, secrete a sticky secretion and act as adhesive papillae. The edge anchors are phylogenetically derived from Rhopalia and are therefore transformed tentacles. Some of them are secondary or absent. The calyx carries the gastric filaments and the gonads.

The mouth disk is sunk in the shape of a funnel and carries the four-lobed mouthpipe (manubrium). The gastric space is divided into 4 gastric pockets by 4 wall-mounted septa. In the septa there are septal muscles and 4 pronounced septal funnels. Each gastric pocket can be divided into an outer and an inner pocket by a claustrum (suborder Cleistocarpida).

The semi-sessile species can attach themselves to the ground with a widened foot disk and detach again to eat or after irritation. Some species secrete a chitin- like substance that binds firmly to the substrate so that they can no longer move. There is an annual cycle in development.

Reproduction

Stauromedusae are separate sexes. The eggs enter the stomach by rupturing the gonadal wall and are released into the surrounding water through the mouth. There is no typical planula stage, but rather a worm-shaped, uncultivated larva that can crawl. The creeping stage lacks a gastric space, the endoderm is stacked like a roll of money. The creeping larvae can reproduce asexually by budding. After attachment, the larva first transforms into a polypoid shape, later by differentiation into the typical cup shape. Most species develop in a dormant phase. The polyp contracts and forms a shell (encystation), in which it u. U. survives months before it transforms into the typical stick jellyfish. Asexual reproduction has not yet been observed in adult animals; they reproduce exclusively sexually. A specialty can be observed in the species Stylocoronella riedli . Here the polyp already has pigment eyes. This is so far unique in the phylum of the cnidarians.

The Stauromedusae are sexually mature in summer and die after reproduction. In winter they reproduce asexually from the larval stage. Some larger species are believed to be perennial.

Distribution and way of life

The pedunculate jellyfish are common worldwide. However, nowhere are they particularly common. 80% of the species are restricted to the northern hemisphere. Most species of jellyfish and long-tailed jellyfish usually live in temperate to cold waters on rocky coasts, from the tidal range to the shallow subtidal. They mostly live attached to algae and seagrasses, a few species (e.g. Stylocoronella riedli ) have also been found living in the wild in the interstitial area of ​​coarse sands. Only Kishinouyea corbini Larson, 1980 occurs on the tropical coast of Espírito Santo , Brazil and in Puerto Rico. In the meantime, pedunculate jellyfish have also been found on the mid-ocean ridges, on so-called hydrothermal vents , where they are found very locally e.g. T. are extremely common. The greatest known depth from which specimens of long-tailed jellyfish have been detected so far is 2700 m.

Very little is known about the way of life. In the gastric contents of about 3700 examined copies (medusae) of Haliclystus auricula of southern Chile following prey animals were detected: harpacticoide copepods (Copepoda) (68.4%), gamma ride flea crabs (Amphipoda) (15 · 4%), biting midges larvae (Chironomidae ) (9.2%) and shellfish (Ostracoda) (5.9%). Very subordinate (1.1%) were found empididae larvae (Empididae), polychaetes , isopods (Isopoda), juvenile decapode crabs and snails (Gastropoda).

Systematics

A jellyfish Haliclystus octoradiatus (on seagrass ) from below
A jellyfish Haliclystus octoradiatus taken from different sides: ol: From above; or: from the side; ul: from below (the suction cup is clearly visible); ur: From the side (on seaweed) using a margin anchor

The order Stauromedusae is described by Daly et al. (2007) divided into two sub-orders with a total of six families:

There are currently around 50 known species, most of which are only a few centimeters tall, the largest species can reach a diameter of 8.5 centimeters and a total height of up to 24 centimeters. Some online databases list yet another family under the order Stauromedusae, Tesseranthidae. It was established by Haeckel (1882) as a subfamily of the Tesseridae Haeckel, 1880. Most authors consider the subfamily to be synonymous with Tesseridae. The Tesseridae (and thus also the Tesseranthidae) are now placed in the class Scyphozoa.

Phylogeny

According to the cladogram of Cnidaria by Collins (2002), the pedunculate jellyfish (Staurozoa) are the sister taxons of the box jellyfish (Cubozoa).

  Cnidaria  


 Hexacorallia 


   

 Octocorallia 


   


 Scyphozoa 


   

 Staurozoa 


   

 Cubozoa 




   

 Hydrozoa 



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Individual evidence

  1. ^ Antonio C. Marques and Allen G. Collins: Cladistic analysis of Medusozoa and cnidarian evolution. Invertebrate Biology, 123 (1): 23-42, 2004 doi : 10.1111 / j.1744-7410.2004.tb00139.x
  2. ^ Heyo Van Iten, Juliana de Moraes Leme, Marcello Guimarães Simões, Antonio Carlos Marques and Allen G. Collins: Reassessment of the phylogenetic position of the conulariids (? Ediacaran – Triassic) within the subphylum Mudusozoa (Phylum Cnidaria). Journal of Systematic Palaeontology, 4 (2): 109-118, 2006 doi : 10.1017 / S1477201905001793
  3. ↑ Michael JE Blumer, Luitfried Salvini-Plawen , Reinhard Kikinger & and Thomas Büchinger: Ocelli in a Cnidaria polyp: the infrastructure of the pigment spots in Stylocoroneila riedli (Scyphozoa, Stauromedusae). Zoomorphology, 115: 221-227, Berlin & Heidelberg 1995 doi: 10.1007 / BF00393802
  4. ↑ Luitfried v. Salvini-Plawen: First record of a free-living stauromedusa Stylocoronella (Cnidaria). PDF
  5. ^ PA Grohmann, MP Magalhaes and Y. Hirano: First Record of the Order Stauromedusae (Cnidaria, Scyphozoa) from the Tropical Southwestern Atlantic, with a Review of the Distribution of Stauromedusae in the Southern Hemisphere. Species Divers, 4 (2): 381-388, 1999 ISSN  1342-1670 Abstract  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / sciencelinks.jp  
  6. ^ Carolina J. Zagal: Diet of the stauromedusa Haliclystus auricula from southern Chile. Journal of the Marine Biological Association of the UK, 84 (2): 337-340 Cambridge 2004 doi : 10.1017 / S0025315404009245h
  7. ↑ Marymegan Daly, Mercer R. Brugler, Paulyn Cartwright, Allen G. Collin, Michael N. Dawson, Daphne G. Fautin, Scott C. France, Catherine S. McFadden, Dennis M. Opresko, Estefania Rodriguez, Sandra L. Romano & Joel L. Stake: The phylum Cnidaria: A review of phylogenetic patterns and diversity 300 years after Linnaeus. Zootaxa, 1668: 127-182, Wellington 2007 ISSN  1175-5326 Abstract - PDF
  8. ^ Claudia E. Mills - University of Washington
  9. ↑ WoRMS - World Register of Marine Species ( Memento of the original from March 5, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.marinespecies.eu
  10. ^ Animal Diversity Web
  11. ↑ Discover Life
  12. ↑ ITIS

literature

  • Gruner (Hrsg.): Textbook of Special Zoology, Volume I: Invertebrates, Part 2 , 4th Edition, 1984, Gustav Fischer Verlag, Stuttgart, ISBN 3-437-20261-8

annotation

  1. ↑ In the older literature, the taxa Cleistocarpida and Eleutherocarpida, which are understood here as subordinates, are often referred to as families (Cleistocarpidae and Eleutherocarpidae). This does not conform to the International Rules for Zoological Nomenclature . These state that a taxon of the family group must be based on a valid generic name. There is neither a genus Cleistocarpus nor a genus Eleutherocarpus.

Web links

Commons : Pedunculate Jellyfish ( Stauromedusae )  - Collection of images, videos and audio files