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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Indirect-developing acorn worms begin life as planktonic, feeding, tornaria larvae that can remain in the water column for up to 300 days (Hadfield, 1978; Nielsen and Hay-Schmidt, 2007).
Functional studies aimed at uncovering the genetic and molecular mechanisms controlling neural regeneration may, in certain cases, be more tractable in the larvae due to their small size, transparency, and relatively simple body plan and tissue architecture compared to adult acorn worms.
Enteropneusts - or acorn worms - are marine animals closely related to starfish and sea urchins.
Tergivelum cinnabarinum is the name given to a vibrant scarlet-orange acorn worm -- cinnabarinum is Latin for cinnabar which is a red colored mineral.
1B), or in both regions (9%, n = 11) of the acorn worms. The number of cysts varied among acorn worm individuals.
A new deep-sea species of epibenthic acorn worm (Hemichordata, Enteropneusta).
An anatomical description of a miniaturized acorn worm (Hemichordata Enteropneusta) with asexual reproduction by paratomy.
The 1984-1987 survey: Examples of the acorn worms and brachiopods collected are included in Fig.
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.
Acorn worms are themselves part of the hemichordates, a group of marine animals closely related to today's sea stars and sea urchins.
The northwest plains were the home of deep-sea enteropneust acorn worms. Only a few specimens, from the Pacific Ocean, were previously known to science," said Professor Monty Priede, Director of the University of Aberdeen's Oceanlab.
In preliminary studies, Shu Degan of Xian Northwest University places Yunnanozoon in another phylum, the hemichordates, which includes the modern acorn worms.