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New species of horseshoe worm discovered in Japan after a 62 year gap

Date:
April 4, 2014
Source:
Pensoft Publishers
Summary:
A team of scientists recently described a new species of horseshoe worm Phoronis emigi from sandy bottom at 33 m depth in Amakusa, Japan. This is the first new horseshoe worm species since the discovery of Phoronis pallida by Silén in 1952, 62 years ago.
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This is a living Phoronis ijimai, extending its lophophore.
Credit: Dr. Masato Hirose; CC-BY 4.0

The horseshoe worm is a worm-like marine invertebrate inhabiting both hard and soft substrates such as rock, bivalve shells, and sandy bottom. The name "horseshoe" refers to the U-shaped crown of tentacles which is called "lophophore." Horseshoe worms comprise a small phylum Phoronida, which contains only ten species decorating the bottom of the oceans.

The new species Phoronis emigi, the eleventh member of the group described in the open access journal ZooKeys, comes after a long 62 year gap of new discoveries in the phylum. It is unique in the number and arrangement of body-wall muscle bundles and the position of the nephridia which is the excretory organ of some invertebrates. The new species is morphologically similar to sand-dwelling species Phoronis psammophila and it is also closely related to Phoronis hippocrepia, which inhabits hard substrate.

The morphology of the topotypes for Phoronis ijimai is also described in this study after 117 years since its original description. The combination of a detailed observation of the internal morphologies and the molecular phylogenetic analyses including the topotypes ensure a synonymy between P. ijimai and the northeastern pacific species Phoronis vancouverensis that has long been disputed.

"It is necessary to use both internal anatomy and molecular data for reveal the global diversity of horseshoe worm. The known phoronid diversity still remains low, with all specimens reported from limited habitats and the localities by the limited reports. Investigations at new localities or habitats may yield additional species in the future," explains Dr Masato Hirose, Atmosphere and Ocean Research Institute, The University of Tokyo, Japan.


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The above post is reprinted from materials provided by Pensoft Publishers. The original story is licensed under a Creative Commons License. Note: Materials may be edited for content and length.


Journal Reference:

  1. Masato Hirose, Ryuma Fukiage, Toru Katoh, Hiroshi Kajihara. Description and molecular phylogeny of a new species of Phoronis (Phoronida) from Japan, with a redescription of topotypes of P. ijimai Oka, 1897. ZooKeys, 2014; 398: 1 DOI: 10.3897/zookeys.398.5176

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Pensoft Publishers. "New species of horseshoe worm discovered in Japan after a 62 year gap." ScienceDaily. ScienceDaily, 4 April 2014. <www.sciencedaily.com/releases/2014/04/140404092935.htm>.
Pensoft Publishers. (2014, April 4). New species of horseshoe worm discovered in Japan after a 62 year gap. ScienceDaily. Retrieved August 30, 2015 from www.sciencedaily.com/releases/2014/04/140404092935.htm
Pensoft Publishers. "New species of horseshoe worm discovered in Japan after a 62 year gap." ScienceDaily. www.sciencedaily.com/releases/2014/04/140404092935.htm (accessed August 30, 2015).

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