Turritopsis
| Turritopsis | ||||||||||||
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Type species Turritopsis nutricula |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Turritopsis | ||||||||||||
| McCrady , 1857 |
Turritopsis is agenus of hydrozoans in the family Oceaniidae . In some places, such as the English Channel and New Zealand , Turritopsis speciescan stand out due to their red color and are known to beach-goers, fishermen and nature lovers. In the last few years, their ability to reverse their life cycle from adult to youthful life has made theirway into newspapers and science journalsas potentially immortal jellyfish .
features
In the polyp stage , Turritopsis species form upright, branched hydroid colonies. The polyp heads (hydrant) are spindle-shaped to club-shaped, their thread-like tentacles are scattered over a large part of the hydrant body. The medusa buds (gonophores) develop on the stems (hydrocauli) in a region enveloped with perisarc and are released as medusa.
The four lips of the medusa are covered with numerous round groups of sessile nettle cells (nematocysts). The tentacles are numerous and evenly distributed. The ocelles (eyes) sit adaxially at the base of the tentacles. Large Turritopsis medusas are similar to Oceania medusas, but the groups of nettle cells along the mouth in Oceania are clearly stalked and in Turritopsis without a clearly recognizable stem.
distribution
Medusa of the species of the genus Turritopsis occur worldwide in temperate to tropical waters.
Systematics
Most of the species were seen as synonyms of Turritopsis nutricula or taken for Turritopsis nutricula , Turritopsis nutricula seemed to be distributed worldwide. The problem is that the descriptions are often based solely on the polyp or medusa stage and the entire life cycle is insufficiently known. However, almost identical hydroids can produce very different medusas, sometimes even across family boundaries. However, a review based on morphological and reproductive characteristics confirmed by molecular studies has shown that there are several different valid species. The situation of the Japanese turritopsis is particularly complex. All populations are clearly different from Turritopsis nutricula . One of them, probably Turritopsis pacifica , is closely related to Turritopsis rubra . A second clade , potentially undescribed, develops smaller medusa than Turritopsis pacifica . The third Japanese group is identical to the species Turritopsis dohrnii, which is common in the Mediterranean, and was probably introduced through human activity. The Japanese turritopsis are also listed as small southern morphs and northern large morphs, further investigations are necessary here.
Turritopsis is monophyletic , 7 species are described in the genus:
- Turritopsis dohrnii ( Weismann , 1883) - Mediterranean
- Turritopsis lata Lendenfeld , 1885
- Turritopsis minor ( Nutting , 1906)
- Turritopsis nutricula McCrady , 1857 - Northwest Atlantic , New England to Brazil
- Turritopsis pacifica Maas , 1909 - Northern Japan (large morph), the small morph (possibly a different species) southern Japan.
- Turritopsis polycirrha ( Keferstein , 1862)
- Turritopsis rubra ( Farquhar , 1895) - New Zealand and Tasmania
Individual evidence
- ↑ a b c d e f g M. P. Miglietta, S. Piraino, S. Kubota, P. Schucher: Species in the genus Turritopsis (Cnidaria, Hydrozoa): a molecular evaluation. 2006, in: Journal of Zoological Systematics and Evolutionary Research 45 (1), pp. 11-19. doi : 10.1111 / j.1439-0469.2006.00379.x ( online )
- ↑ a b Peter Schuchert: Revision of the European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Families Oceanidae and Pachycordylidae. In: Rev. Suisse Zool. , Vol. 111 (2), 2004, pp. 315-369. PDF
- ↑ Turritopsis at WoRMS (World Register of Marine Species)
