acorn worm


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acorn worm:

see HemichordataHemichordata
, small phylum of marine invertebrates closely related to both the echinoderms (phylum Echinodermata) and chordates (phylum Chordata). Acorn worms, class Enteropneusta, are the most common hemichordates.
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acorn worm

[′ā‚kȯrn ‚wərm]
(invertebrate zoology)
Any member of the class Enteropneusta, free-living animals that usually burrow in sand or mud. Also known as tongue worm.
References in periodicals archive ?
Hemichordates are a type of marine animal split into two groups: the acorn worm, which live in burrows, and the pterobranchs, which live in a tubular structure anchored to the ocean floor.
Enteropneusts - or acorn worms - are marine animals closely related to starfish and sea urchins.
Allapasus isidis is the name given to a white acorn worm which was named after the NERC-owned remotely operated vehicle, ROV Isis, which collected the specimens from the ocean.
One gene cluster preserved for more than half a billion years is though to be linked to the development of the pharynx - the passageway linking the nasal cavity to the mouth and throat - in both acorn worms and vertebrates.
Christopher Cameron of the University of Montreal's Department of Biological Sciences and his colleagues have confirmed that Spartobranchus tenuis is a member of the acorn worms group, which are seldom-seen animals that thrive today in the fine sands, and mud of shallow and deeper waters.
The northwest plains were the home of deep-sea enteropneust acorn worms.
In preliminary studies, Shu Degan of Xian Northwest University places Yunnanozoon in another phylum, the hemichordates, which includes the modern acorn worms.