| Abstract from DBPedia | Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 14 families within the order; 35 extant genera, and it is estimated that of 450 described species, around 200 are valid. Sea pens have a cosmopolitan distribution, being found in tropical and temperate waters worldwide, as well as from the intertidal to depths of more than 6100 m. Sea pens are grouped with the octocorals, together with sea whips (gorgonians). Although the group is named for its supposed resemblance to antique quill pens, only sea pen species belonging to the suborder Subselliflorae live up to the comparison. Those belonging to the much larger suborder Sessiliflorae lack feathery structures and grow in club-like or radiating forms. The latter suborder includes what are commonly known as sea pansies. The earliest accepted fossils are known from the Cambrian-aged Burgess Shale (Thaumaptilon). Similar fossils from the Ediacaran (ala Charnia) may show the dawn of sea pens. Precisely what these early fossils are, however, is not decided.ウミエラ（海鰓・Sea-pen）は、刺胞動物門花虫綱八放サンゴ亜綱ウミエラ目ウミエラ科に属する腔腸動物の群体であり、羽毛状で羽ペンのような形をしている。体長は10〜20cmで、日本近海・西太平洋の砂泥底などに生息する。海底に直立する。、、などの種がいる。最大種は、全長2mに達するである。 ウミエラの多くは夜行性であり、昼間は体を収縮させて海底の砂中に潜り、夜になると砂上に姿を現して餌を摂取する。襞の部分にはポリプが無数に並び、水流に合わせることで効率的にプランクトンを摂食している。 (Source: http://dbpedia.org/resource/Sea_pen) |
