page_title: Echiura
section_title: Distribution and habitat
hierarchical_section_title: Echiura / Distribution and habitat
caption_attribution_description: Ochetostoma erythrogrammon Japanese name:Sujiyumusi：スジユムシ Date;2009,10.04;Tanabe City, Wakayama prefecture, Japan Author;Keisotyo
context_page_description: The Echiura, or spoon worms, are a small group of marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids typically have their bodies divided into segments, but echiurans have secondarily lost their segmentation. The majority of echiurans live in burrows in soft sediment in shallow water, but some live in rock crevices or under boulders, and there are also deep sea forms. More than 230 species have been described.
  Spoon worms are cylindrical, soft-bodied animals usually possessing a non-retractable proboscis which can be rolled into a scoop-shape to feed. In some species the proboscis is ribbon-like, longer than the trunk and may have a forked tip. Spoon worms vary in size from less than a centimetre in length to more than a metre.
  Most are deposit feeders, collecting detritus from the sea floor. Fossils of these worms are seldom found and the earliest known fossil specimen is from the Upper Carboniferous.
context_section_description: Echiurans are exclusively marine and the majority of species live in the Atlantic Ocean. They are mostly infaunal, occupying burrows in the seabed, either in the lower intertidal zone or the shallow subtidal (e.g. the genera Echiurus, Urechis, and Ikeda). Others live in holes in coral heads, and in rock crevices. Some are found in deep waters including at abyssal depths; in fact more than half the 70 species in Bonelliidae live below 3,000 m (10,000 ft). They often congregate in sediments with high concentrations of organic matter. One species, Lissomyema mellita, which lives off the southeastern coast of the US, inhabits the tests (exoskeleton) of dead sand dollars. When the worm is very small, it enters the test and later becomes too large to leave.
  In the 1970s, the spoon worm Listriolobus pelodes was found on the continental shelf off Los Angeles in numbers of up to 1,500 per square metre (11 square feet) near sewage outlets. The burrowing and feeding activities of these worms churned up and aerated the sediment and promoted a balanced ecosystem with a more diverse fauna than would otherwise have existed in this heavily polluted area.
caption: Ochetostoma erythrogrammon
exif: {}