''Arachnanthus sarsi'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of tube-dwelling anemone in the family

Arachnactidae Arachnactidae is a family of tube-dwelling anemones in the order Ceriantharia. It is the only family in the monotypic order Penicillaria and comprises around 38 species. They differ from other ceriantharians in the makeup of their cnidome (the t ...

. This species is found in the North Atlantic in subtidal sand or muddy sand at depths of 15–130 m.

Description

This is a large sea anemone, with a diameter of up to when fully expanded and a height of a similar amount. There are two whorls of tentacles, the outer ring of about thirty are long and slender, while the inner ring, consisting of a similar number, are short and are extended upward, turning inward at the tip to form a cone; it is this feature which distinguishes this species from the otherwise similar ''

Cerianthus lloydii ''Cerianthus lloydii'' is a species of tube-dwelling sea anemone in the family Cerianthidae. It is sometimes called the lesser cylinder anemone and is found in shallow seas around the coasts of north west Europe. Taxonomy ''Cerianthus lloydii'' ...

''. The tentacles are indistinctly banded. It lives in soft sand, muddy sand, mud or gravel, with its column concealed in a parchment-like tube.

Distribution

This species was described from

Trondheim Fjord The Trondheim Fjord or Trondheimsfjorden (), an inlet of the Norwegian Sea, is Norway's third-longest fjord at long. It is located in the west-central part of the country in Trøndelag county, and it stretches from the municipality of Ørland in ...

, Norway. It occurs in the north-east Atlantic Ocean off

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

and Ireland.Picton, B.E.; Manuel, R.L. 1985. Arachnanthus sarsi'' Carlgren, 1912, a redescription of a cerianthid anemone new to the British Isles.'' Zoological Journal of the Linnean Society 83 pp.343-349. In Northern Ireland it is known only from the southern half of

Rathlin Island Rathlin Island ( ga, Reachlainn, ; Local Irish dialect: ''Reachraidh'', ; Scots: ''Racherie'') is an island and civil parish off the coast of County Antrim (of which it is part) in Northern Ireland. It is Northern Ireland's northernmost point. ...

. It seems to be rare in Northern Ireland, but this may be because it is at least partly

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

and may have been overlooked.

References

Arachnactidae Animals described in 1912 {{anthozoa-stub