''Leptometra celtica'' is a marine invertebrate and

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 ...

crinoid Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...

or feather star of the Leptometra

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Antedonidae Antedonidae is a family of crinoids or feather stars in the phylum Echinodermata. Members of the family are unstalked and have ten feathery arms. They can move about freely and have clawed cirri to attach them temporarily to structures.

. It is found in the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

around the coasts of north west Europe. The presence of ''L. celtica'' and '' L. phalangium'' (its counterpart in the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

) is considered to be a good indication of nearby shelf breaks, general bottom currents, and areas of high gross productivity as they are suspension-feeders, hence their proliferation in productive environments.

Description

''Leptometra celtica'' has ten pinnate arms that are typically 7–10 cm in length with neatly held side branches. The arms may be banded in red and white or plain coloured in brown, white or red. In areas of moderate current, specimens have been observed to spread their arms out into a vertical fan across the current.Encyclopedia of Marine Life of Britain and Ireland. Retrieved 2013-12-03. The

cirri Giovanni Battista Cirri (1 October 1724 – 11 June 1808) was an Italian cellist and composer in the 18th century. Biography Cirri was born in Forlì in the Emilia-Romagna Region of Italy. He had his first musical training with his brother ...

of ''L. celtica'' are about 34–40 mm in length and vary in color from green to white. They are arranged in irregular columns dimorphically about the organism's stalk allowing for locomotion and attachment to deep sea structures. Examination of cirri can help distinguish ''L. celtica'' from the related ''L. phalangium'' as the cirri of ''L. celtica'' are shorter in proportion and are not evenly tapered distally. The distal segments of the cirri have their distal edge slightly swollen so that the organism's dorsal profile retains a slightly scalloped appearance in comparison to ''L. phalangium''. ''L. celtica'' has short proximal oral pinnule segments protruding from its stalk to allow for feeding. Its oral pinnules are arranged in irregular columns are somewhat shorter in length in comparison to ''L. phalangium''. The four lowest pinnules average between 12–17 mm. The opening of the centrodorsal cavity in ''L. celtica'' is only 0.35 of the centrodorsal diameter, making it similar to that of other species of antedonids.

Distribution and habitat

''L. celtica'' can be found in the Atlantic Ocean ranging from the coasts of the United Kingdom and Faroe Islands to the Moroccan coast. The species has been found at depths between 20 and 1247 m in the western Mediterranean and has been studied in the Algarve region on the southwest coast of Portugal. ''L. celtica'' has also been studied along shelf breaks ranging from northwest Spain to the southwest coasts of Ireland. The species can be typically found in sandy to muddy sand types of sediment.

Ecology

''L. celtica'' are suspension feeders that take in organic particles that fall from the photic zone. Shelf-break upwelling and water turbulence increases the transportation of organic matter up the water column, leading to high-concentrations of crinoids like ''L. celtica'' that feed on organic matter around these shelf breaks. The species plays an important role in marine environments by taking in large amounts of organic particles and regulating food chain production. For this reason, the presence of

benthopelagic fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They o ...

alongside crinoids like ''L. celtica'' can serve as indicators of highly productive regions of shelf-breaks.

Human impact

Several studies have focused on the impact of

bottom trawling Bottom trawling is trawling (towing a trawl, which is a fishing net) along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towin ...

and

dredging Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing da ...

on crinoid communities along the coast. ''L. celtica'' has been found in crinoid beds with a high abundance of juvenile commercial fish and crustacea, and research has shown that heavily towed benthic environments have much lower numbers of crinoid taxa like ''L. celtica''.

References

{{Taxonbar, from=Q2881870 Antedonidae Animals described in 1857