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Morphology of a new deep-sea acorn worm (class Enteropneusta, phylum Hemichordata): A part-time demersal drifter with externalized ovaries

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dc.contributor.author Holland, Nicholas D. en
dc.contributor.author Kuhnz, Linda A. en
dc.contributor.author Osborn, Karen J. en
dc.date.accessioned 2018-08-31T18:27:57Z
dc.date.available 2018-08-31T18:27:57Z
dc.date.issued 2012
dc.identifier.citation Holland, Nicholas D., Kuhnz, Linda A., and Osborn, Karen J. 2012. "<a href="https://repository.si.edu/handle/10088/81565">Morphology of a new deep‐sea acorn worm (class Enteropneusta, phylum Hemichordata): A part‐time demersal drifter with externalized ovaries</a>." <em>Journal of Morphology</em>. 273 (7):661&ndash;671. <a href="https://doi.org/10.1002/jmor.20013">https://doi.org/10.1002/jmor.20013</a> en
dc.identifier.issn 0362-2525
dc.identifier.uri https://hdl.handle.net/10088/81565
dc.description.abstract Ten individuals of an enteropneust in the family Torquaratoridae were videotaped between 2, 900 and 3, 500 m in the Eastern Pacific one drifting a few centimeters above the bottom, two exposed on the substrate, and seven partly burrowed, reflecting a bentho-pelagic life style. Here, we describe a captured specimen (26 cm living length) as the holotype of Allapasus aurantiacus n. gen., n. sp. The small proboscis is dome-shaped, and the collar is only slightly wider than deep; both of these body regions are more muscular than in other torquaratorids, which presumably facilitates burrowing. The proboscis complex, in contrast to that of shallow-living enteropneusts, lacks a pericardial sac and is located relatively posteriorly in the proboscis stalk. The stomochord is separated from the main course of the gut by the intervention of a small, plate-like proboscis skeleton lacking posterior horns. The most anterior region of the trunk houses the pharynx, in which the pharyngeal skeletal bars are not connected by synapticles. The postpharyngeal trunk comprises three intestinal regions: prehepatic, hepatic (with conspicuous sacculations), and posthepatic. On either side of the worm, a flap of body wall (lateral wing) runs the entire length of the trunk. The two lateral wings can wrap the body so their edges meet in the dorsal midline, although they often gape open along the pharyngeal region. The holotype is a female (presumably the species is gonochoric) with numerous ovaries located in the lateral wings along the pharyngeal region. Each larger ovary contains a single primary oocyte (up to 1, 500 µm in diameter) and bulges outwards in an epidermal pouch attached to the rest of the body by a slender stalk. Such externalized ovaries are unprecedented in any animal, and nothing is yet known of their role in the reproductive biology of A. aurantiacus. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc. en
dc.relation.ispartof Journal of Morphology en
dc.title Morphology of a new deep-sea acorn worm (class Enteropneusta, phylum Hemichordata): A part-time demersal drifter with externalized ovaries en
dc.type Journal Article en
dc.identifier.srbnumber 110474
dc.identifier.doi 10.1002/jmor.20013
rft.jtitle Journal of Morphology
rft.volume 273
rft.issue 7
rft.spage 661
rft.epage 671
dc.description.SIUnit NH-Invertebrate Zoology en
dc.description.SIUnit NMNH en
dc.description.SIUnit Peer-reviewed en
dc.citation.spage 661
dc.citation.epage 671


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