Urticinopsis antarctica
{{Short description|Species of sea anemone}}
{{Speciesbox
| taxon = Urticinopsis antarctica
| authority = (Verrill, 1922) {{cite WoRMS |author= Fautin, Daphne |year=2015 |title=Urticinopsis antarctica (Verrill, 1922) |id=231822 |accessdate=11 February 2017|db=}}
| synonyms =
- Rhodactinia clubbi Pax
- Urticina antarctica Verrill, 1922
}}
Urticinopsis antarctica is a species of sea anemone in the family Actiniidae. It is found in the Southern Ocean around Antarctica.
Description
Distribution
Urticinopsis antarctica is a common species in Antarctic and Subantarctic waters. It has been recorded at McMurdo Sound, the South Shetland Islands, Prydz Bay, the Cosmonauts Sea, the Haswell Islands in the Davis Sea, and the Weddell Sea.{{cite journal |author=Ivanova, N. Yu |author2=Grebelnyi, S.D. |year=2016 |title=On the food of the Antarctic sea anemone Urticinopsis antarctica Carlgren, 1927 (Actiniidae, Actiniaria, Anthozoa) |journal=Journal of the Marine Biological Association of the United Kingdom |volume=97 |pages=29–34 |doi=10.1017/S0025315415002131 |s2cid=90578947 }}
Ecology
The waters under the ice packs around Antarctica show a marked zonation. U antarctica is found in Zone II, between {{convert|15|and|33|m|ft|-1|abbr=on}} deep, where it is one of the dominant sessile organisms, alongside various other sea anemones, the soft coral Alcyonium antarcticum, the stoloniferan Clavularia frankliniana and the hydroids Tubularia hodgsoni and Lampra parvula. Here U antarctica mostly feeds on sea urchins in the genus Sterechinus.{{cite book|title=Advances in Marine Biology|url=https://books.google.com/books?id=5TRkC4w8jsoC&pg=PA148 |year=1972 |publisher=Academic Press |isbn=978-0-08-057933-7 |pages=148–149}}
It is also present in Zone III, deeper than {{convert|33|m|ft|-1|abbr=on}} and below the depth at which anchor ice forms. Here the seabed is characterised by a layer of sponge spicules and dead mollusc shells a metre or more thick, with living sponges growing on the surface. In this zone it preys on the various species of starfish found here, grazing on and feeding among the sponges, such as Diplasterias brucei.[http://afg.biodiversity.aq/species/86-diplasterias-brucei Diplasterias brucei; (Koehler, 1908)] Antarctic Field Guide. Retrieved 11 February 2017. Examination of the contents of the gastrovascular cavities of these sea anemones show that the diet can include sea urchins, starfish, sea cucumbers, brittle stars, crinoids, gastropod and bivalve molluscs, and small fish; also found in the stomach cavities, but completely undigested, were several amphipod crustaceans, and these are hypothesised to have been living there as commensals.