A new bizarrely shaped spoon worm, Arhynchite hayaoi, from Japan

June 27th, 2013 in Biology / Plants & Animals
A new bizarrely shaped spoon worm, Arhynchite hayaoi, from Japan
This image shows the new spoon worm species, Arhynchite hayaoi. Credit: Teruaki Nishikawa


This image shows the new spoon worm species, Arhynchite hayaoi. Credit: Teruaki Nishikawa

A new species of the peculiarly shaped spoon worms has been recently discovered in Japan, and described in the open access journal Zookeys. These animals derive their name from their elongated and spoon-like projection (the proboscis), issuing from the barrel- or sweet potato-like roundish body proper (the trunk).

The new species Arhynchite hayaoi was discovered on a sandy tidal flat named Hachi-no-higata of the Seto Inland Sea, Japan. Like most spoon worms, the new species has the typical peculiar spoon shaped . The animal is of a pinkish-yellow colour, and its body length reaches about 10 cm in total.

Spoon worms, scientifically called Echiura, are a small group of exclusively . Although they are members of annelid worms, most of which has segmented structure, they have lost segmentation during their evolutionary history. Like the new species from Japan, most spoon worms live in shallow waters, but some are connected with deep sea waters. Most representatives are deposit feeders, which means that they use their "spoon" to collect or fragments from their surroundings.

A new bizarrely shaped spoon worm, Arhynchite hayaoi, from Japan
"Hachi-no-higata" is where the new spoon worm was discovered. Credit: Masaatsu Tanaka

Previously confused with a different species, the newly described spoon worm used to be in fact rather abundant and collected in great numbers from intertidal to subtidal sandy bottoms for fish bait in the Seto Inland Sea, Japan. Now that the true identity of the species is recognised, it seems to be in decline, with numbers dropping to a point where the spoon worm lost this economic importance.

More information: ZooKeys 312: 13–21, doi: 10.3897/zookeys.312.5456.

Provided by Pensoft Publishers

"A new bizarrely shaped spoon worm, Arhynchite hayaoi, from Japan." June 27th, 2013. http://phys.org/news/2013-06-bizarrely-spoon-worm-arhynchite-hayaoi.html