''Pseudorhiza haeckeli'', or Haeckel's jelly, is a species of

cnidarian 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, ...

of the family

Lychnorhizidae Lychnorhizidae is a family of Scyphozoa, true jellyfish. Species The following species are recognized in the family Lychnorhizidae: * ''Anomalorhiza'' :*''Anomalorhiza shawi'' Light, 1921 * ''Lychnorhiza'' :*''Lychnorhiza arubae'' Stiasny, 192 ...

. The species is a carnivore with a mild sting. It is native to temperate and sub-tropical Australian marine waters. It has been observed at depths of 1-30 metres, and is sometimes found cast on beaches. It was described by the naturalist

Wilhelm Haacke Johann Wilhelm Haacke (23 August 1855 – 6 December 1912) was a German zoologist born in Clenze, which is now Lower Saxony, who served as Director of the South Australian Museum in Adelaide from 1882 to 1884. Career He studied zoology at th ...

in 1884, and named for his mentor

Ernst Haeckel Ernst Heinrich Philipp August Haeckel (; ; 16 February 1834 – 9 August 1919) was a German zoologist, natural history, naturalist, eugenics, eugenicist, Philosophy, philosopher, physician, professor, marine biology, marine biologist and artist ...

Description

The animal has a bell which is round with raised, warty lumps on the upper surface. It has a cross-shaped structure inside the bell. Its arms curve around the bottom of the bell and a long, colourful tail trails below it. It possesses no tentacles. Its bell and arms are reasonably transparent. Tail length varies depending on the individual, as it may be in a stage of regeneration. Its bell can reach a diameter of 40 cm.

Biology

The tail of Haeckel's Jellyfish can be damaged while capturing prey and may be attacked by other animals. The warty lumps on the bell and the curved arms contain stinging cells, to which humans are only mildly sensitive. This jelly is often seen in association with amphipods, parasitic anemones or schools of small fishes which shelter around its arms and bell. All members of its class,

Scyphozoa The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or "true jellies"). The class name Scyphozoa comes from the Greek word '' skyphos'' (), denoting a kind of drinking cup and alluding to the ...

, are

gonochoric In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contrast ...

. The egg is laid by an adult medusa. It then develops into a free-living

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 ...

, then to a

scyphistoma The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or "true jellies"). The class name Scyphozoa comes from the Greek word ''skyphos'' (), denoting a kind of drinking cup and alluding to the ...

to a strobila, and finally into a free-living young medusa.

References

{{Taxonbar, from=Q1920606 Animals described in 1884 Lychnorhizidae Marine fauna of Australia