Aurelia (cnidarian)

Aurelia is a genus of jellyfish that are commonly called moon jellies, which are in the class Scyphozoa. There are currently 25 accepted species and many that are still not formally described.[1][2][3]

Aurelia
Adult Aurelia aurita medusa
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Cnidaria
Class: Scyphozoa
Order: Semaeostomeae
Family: Ulmaridae
Genus: Aurelia
Lamarck, 1816
Species

The genus was first described in 1816 by Jean-Baptiste Lamarck in his book Histoire Naturelle des Animaux sans Vertèbres (Natural History of Invertebrates).[4] It has been suggested that Aurelia is the best-studied group of gelatinous zooplankton, with Aurelia aurita the best-studied species in the genus; two other species, Aurelia labiata and Aurelia limbata were also traditionally investigated throughout the 20th century.[5] In the early 2000s, studies that considered genetic data showed that diversity in Aurelia was higher than expected based solely on morphology,[6][7] so one cannot confidently attribute the results from most of the previous studies to the species named. More recently, studies have highlighted the morphological variability[2] (including the potential for phenotypic plasticity[8][9]) in this genus, emphasizing the difficulty of identifying cryptic species.[10]

Species of Aurelia can be found in the Atlantic, Arctic, Pacific and Indian Oceans, and seem to be more common in temperate regions, such as in the waters off northern China, Japan, Korea, New Zealand, the northeastern and northwestern coasts of the United States, and those of northern Europe.[2]

Aurelia undergoes alternation of generations, whereby the sexually-reproducing pelagic medusa stage is either male or female, and the benthic polyp stage reproduces asexually. Meanwhile, life cycle reversal, in which polyps are formed directly from juvenile and sexually mature medusae or their fragments, was also observed in Aurelia coerulea (= Aurelia sp. 1).[11]

Two Aurelia aurita in Gullmarn fjord, Sweden

Appearance

The similar appearances of moon jellyfish is what has made them so hard to identify. They tend to have a variety of different sizes, however, they typically range from 5–38 cm (2.0–15.0 in) in diameter with an average of 18 cm (7.1 in) wide and 8 cm (3.1 in) in height.[12] The polyps of these jellyfish can grow to 1.6 cm (0.63 in) tall and their ephyrae have an average diameter of 0.4 cm (0.16 in).[13] The adult medusae are typically translucent in color[13] but the color of their gut can change based on what they eat; for example, if they eat crustaceans, they can have a pink or lavender tint to them and if they were to eat brine shrimp, the tint would be more of an orange color.[14] Their polyps usually have around 16 tentacles (although Aurelia insularia has 27-33 tentacles)[2][15] which mostly help with feeding.[13]

Feeding
Aurelia aurita in Åbyfjorden, Sweden

The diet of Aurelia is similar to that of other jellyfish. They primarily feed on zooplankton.[12] They may prey on or compete with commercially important fish and their larvae, as well as cause several issues for trawling boats when large aggregations occur,[16] as they may clog and damage fishing nets as well as force fisherman to relocate.[17]

Characteristics

They are able to sense light and dark and up and down due to rhopalia around the bell margin.[12] After many tests on frogs, it was determined that A. aurita has a proteinaceous venom that causes muscle twitching by inducing the irreversible depolarization of the muscle membrane that is believed to be caused by an increase in the membrane’s permeability to sodium ions.[18]

Reproduction
Aurelia aurita in Limfjord, Aalborg, Denmark

The medusa stage of the jellyfish reproduce sexually. The males release strings of sperm and the females ingest them.[14] Once the ciliated larvae develop from the egg, they settle on or near the sea floor and develop into benthic polyps. The polyps then reproduce asexually and bud into ephyrae which later turn into medusae.

See also

References
  1. Collins, A. G.; Jarms, G.; Morandini, A. C. (September 12, 2021). "World List of Scyphozoa. Aurelia Lamarck, 1816". WoRMS. World Register of Marine Species. Retrieved September 12, 2021.
  2. Lawley, J. W.; Gamero-Mora, E.; Maronna, M. M.; Chiaverano, L. M.; Stampar, S. N.; Hopcroft, R. R.; Collins, A. G.; Morandini, A. C. (2021). "The importance of molecular characters when morphological variability hinders diagnosability: systematics of the moon jellyfish genus Aurelia (Cnidaria: Scyphozoa)". PeerJ. 9:e11954: e11954. doi:10.7717/peerj.11954. PMC 8435205. PMID 34589293.
  3. Brown, M.; Scorrano, S.; Kuplik, Z.; Kuyper, D.; Ras, V.; Thibault, D.; Engelbrecht, A.; Gibbons, M. J. (2021). "A new macromedusa from the coast of Mozambique: Aurelia mozambica sp. nov. (Scyphozoa: Ulmaridae)". Zootaxa. 4933 (2): 263–276. doi:10.11646/zootaxa.4933.2.5. hdl:10566/6168. PMID 33756798. S2CID 232339936.
  4. Lamarck, J.-B. M. de. (1816). "Histoire naturelle des animaux sans vertèbres". www.biodiversitylibrary.org. Verdière: Biodiversity Heritage Library. Archived from the original on 2014-05-13. Retrieved 23 June 2021.
  5. Arai, Mary Needler. A Functional Biology of Scyphozoa. London: Chapman and Hall. pp. 68–206.
  6. Schroth, Werner; Jarms, Gerhard; Streit, Bruno; Schierwater, Bernd (2 January 2002). "Speciation and phylogeography in the cosmopolitan marine moon jelly, Aurelia sp". BMC Evolutionary Biology. 2: 1. doi:10.1186/1471-2148-2-1. PMC 64640. PMID 11801181.
  7. Dawson, Michael N (2003). "Macro-morphological variation among cryptic species of the moon jellyfish, Aurelia (Cnidaria: Scyphozoa)". Marine Biology. 143 (2): 369–379. doi:10.1007/s00227-003-1070-3. S2CID 189820003.
  8. Chiaverano, Luciano M.; Bayha, Keith W.; Graham, William M. (2016-06-22). Colgan, Donald James (ed.). "Local versus Generalized Phenotypes in Two Sympatric Aurelia Species: Understanding Jellyfish Ecology Using Genetics and Morphometrics". PLOS ONE. 11 (6): e0156588. Bibcode:2016PLoSO..1156588C. doi:10.1371/journal.pone.0156588. ISSN 1932-6203. PMC 4917110. PMID 27332545.
  9. Chiaverano, Lm; Graham, Wm (2017-11-06). "Morphological plasticity in Aurelia polyps, with subsequent effects on asexual fecundity and morphology of young medusae". Marine Ecology Progress Series. 582: 79–92. Bibcode:2017MEPS..582...79C. doi:10.3354/meps12314. ISSN 0171-8630. S2CID 90233141.
  10. Lawley, Jonathan W.; Gamero-Mora, Edgar; Maronna, Maximiliano M.; Chiaverano, Luciano M.; Stampar, Sérgio N.; Hopcroft, Russell R.; Collins, Allen G.; Morandini, André C. (2022-09-29). "Morphology is not always useful for diagnosis, and that's ok: Species hypotheses should not be bound to a class of data. Reply to Brown and Gibbons (S Afr J Sci. 2022;118(9/10), Art. #12590)". South African Journal of Science. 118 (9/10). doi:10.17159/sajs.2022/14495. ISSN 1996-7489. S2CID 252562185.
  11. He, Jinru; Zheng, Lianming; Zhang, Wenjing; Lin, Yuanshao; Steele, Robert E. (21 December 2015). "Life Cycle Reversal in Aurelia sp.1 (Cnidaria, Scyphozoa)". PLOS ONE. 10 (12): e0145314. Bibcode:2015PLoSO..1045314H. doi:10.1371/journal.pone.0145314. PMC 4687044. PMID 26690755.
  12. "Moon Jellyfish". www.dwazoo.com. Dallas World Aquarium. 2 December 2013. Retrieved 23 June 2021.
  13. Fletcher, McKenzie. "Aurelia". Animal Diversity Web. Retrieved 23 June 2021.
  14. "Moon jelly". www.montereybayaquarium.org/. Monterey Bay Aquarium. Retrieved 23 June 2021.
  15. Gambill, Maria; Jarms, Gerhard (2014-12-26). "Can Aurelia (Cnidaria, Scyphozoa) species be differentiated by comparing their scyphistomae and ephyrae?". European Journal of Taxonomy (107). doi:10.5852/ejt.2014.107. ISSN 2118-9773.
  16. Försterra, Günter; Häussermann, Vreni (2009). "First Record of the Moon Jellyfish, Aurelia for Chile" (PDF). Spixiana. 32 (1): 3–7.
  17. Conley, Keats R.; Sutherland, Kelly R. (1 June 2015). "Commercial fishers' perceptions of jellyfish interference in the Northern California Current". ICES Journal of Marine Science. 72 (5): 1565–1575. doi:10.1093/icesjms/fsv007.
  18. Ponce, Dalia; López-Vera, Estuardo; Aguilar, Manuel B.; Sánchez-Rodríguez, Judith (6 December 2013). "Preliminary Results of the in Vivo and in Vitro Characterization of a Tentacle Venom Fraction from the Jellyfish Aurelia aurita". Toxins. 5 (12): 2420–2433. doi:10.3390/toxins5122420. PMC 3873694. PMID 24322597.
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