''Thysanocardia procera'' is a marine

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

belonging to the phylum

Sipuncula The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of unsegmented marine annelid worms. The name ''Sipuncula'' is from the genus name ''Sipunculus'', and comes from the Latin ' ...

, the peanut worms. It is a cylindrical, unsegmented

worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wo ...

with a crown of

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work ma ...

s around the mouth. It is native to shallow seas in the northeastern Atlantic Ocean.

Taxonomy

This peanut worm was first described in 1875 by the German zoologist

Karl Möbius Karl August Möbius (7 February 1825 in Eilenburg – 26 April 1908 in Berlin) was a German zoologist who was a pioneer in the field of ecology and a former director of the Museum für Naturkunde in Berlin. Early life Möbius was born in Eilen ...

, who placed it in the genus '' Golfingia'', naming it ''Golfingia procera''. Subsequently, it was moved to ''Thysanocardia'', which was considered to be a subgenus of ''Golfingia''. In a revision of ''Thysanocardia'' in 1983, the subgenus was elevated to full genus rank, with only three species being retained, ''T procera'', a North Atlantic species, the widely distributed '' T. catherinae'', and '' T. nigra'' with a north Pacific distribution.

Description

Like other sipunculans, the body of ''Thysanocardia procera'' is divided into a wide posterior end known as the trunk and a narrower, extendable anterior end known as the introvert. The introvert is several times as long as the trunk when extended, and the whole animal may reach a length of . The surface of trunk and introvert is finely wrinkled, with a dusting of tiny papillae. The

nephridiopore A nephridiopore is part of the nephridium, an excretory organ found in many organisms, such as flatworms and annelids. Polychaetes typically release their gametes into the water column using nephridiopores. Nephridia are homologous to nephrons o ...

s and the anus are at the anterior end of the trunk. The oral disc surrounds the mouth at the tip of the introvert. It consists of eight bundles each containing six to ten

s, arranged in radial or longitudinal rows. A further six to ten short tentacles surrounding the nuchal organ, which has two lobes separated by a groove. There are no hooks on the introvert in this species.

Distribution

This peanut worm occurs in the northeastern Atlantic Ocean. its range includes the

Skagerrak The Skagerrak (, , ) is a strait running between the Jutland peninsula of Denmark, the southeast coast of Norway and the west coast of Sweden, connecting the North Sea and the Kattegat sea area through the Danish Straits to the Baltic Sea. T ...

and the northern part of the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...

, but not the southern part, nor the

English Channel The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" (Cotentinais) or ( Jèrriais), (Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kana ...

. It also occurs in the northwestern Atlantic between about 34°N and 40°N, and has been reported from California, but its precise distribution is unclear. It is found in sandy or silty sediments at depths of from around .

References

{{Taxonbar, from=Q2262499 Sipunculans Animals described in 1875