Stauromedusae are the stalked jellyfishes. They are the sole living members of the

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

Staurozoa Staurozoa is a class of Medusozoa (or jellyfish). It has one extant order: Stauromedusae (stalked jellyfishes) with a total of 50 known species. A fossil group called Conulariida has been proposed as a second order, although this is highly spec ...

and belong to the

medusozoa Medusozoa is a clade in the phylum Cnidaria, and is often considered a subphylum. It includes the classes Hydrozoa, Scyphozoa, Staurozoa and Box jellyfish, Cubozoa, and possibly the parasitic Polypodium (animal), Polypodiozoa. Medusozoans are dis ...

subphylum of

Cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

. They are unique among medusa jellyfish in that they do not have an alternation of polyp and medusa life cycle phases, but are instead interpreted as an attached

medusa In Greek mythology, Medusa (; ), also called Gorgo () or the Gorgon, was one of the three Gorgons. Medusa is generally described as a woman with living snakes in place of hair; her appearance was so hideous that anyone who looked upon her wa ...

stage, with a lifestyle more resembling that of polypoid forms. They have a generally trumpet-shaped body, oriented upside-down in comparison with other jellyfish, with the tentacles projecting upwards, and the stalk located in the centre of the umbrella. Stauromedusae usually has eight marginal arms at the top of the calyx. They reach their adult sizes within several weeks, typically 1 to 4 centimeters in length. Members of this class are commonly found in relatively cold waters, close to the shoreline. However, there are a few known species that inhabit tropical and subtropical waters as referenced in the Stauromedusae article by Claudia E. Mills and Yayoi M. Hirano. Sexually mature stauromedusae free-spawn eggs or sperm, which fertilize in the sea and form a creeping, unciliated

planula A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores, which are not related to cnidarians at all. Some groups of Nemerteans also produce larva ...

larva. The larvae crawl across the sea floor and find a suitable place, attaching themselves typically to rock or algae, where they eventually develop into a new, attached stauromedusa. Unlike most scyphozoan

jellyfish Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animal ...

that practice strobilation, or the process of dividing themselves into body segments, which become new individuals, nearly all stauromedusae develop directly into the adult form. Its primary source of food is small organisms, such as copepods, chironomid fly larvae, podocopid ostracods, amphipods, etc. The tendency for the amount of prey consumed increases with the size of the medusae.

Gallery

File:Haliclystus stejnegeri 1.jpg, ''Haliclystus sp.'' File:Haliclystus antarcticus 1C.jpg, '' Haliclystus antarcticus'' File: Haliclystus_octoradiatus_-_Becherqualle_an_Seegras.jpg , '' Haliclystus octoradiatus'' File: Green subum.jpg, ''

Haliclystus sanjuanensis ''Haliclystus sanjuanensis'' is a species of small (~4 cm) stalked jellyfish found in the Pacific Ocean along the west coast of North America. This species can be found in shallow waters at low tide on soft substrates such as seagrass ('' P ...

'' File:6 or-Manania handi.tif, '' Manania handi'' File:Stalked jelly1.jpg, '' Depastromorpha africana'' File:Lucernaria quadricornis.jpg, '' Lucernaria quadricornis'' File:Bell stalked jelly1.jpg, '' Lipkea spp.''

References

Bibliography

Introduction to Stauromedusae

* agal, C. J. (2004). Diet of the stauromedusa Haliclystus auricula from southern Chile. Journal of the Marine Biological Association of the United Kingdom, 84(2), 337–340.ttps://faculty.washington.edu/cemills/Mills&Hirano2007bStauro.pdf

External links

Staurozoan: The Stalked Jellyfish , Smithsonian Ocean Portal
{{Authority control Staurozoa Ediacaran first appearances Taxa named by Ernst Haeckel