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

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 proboscis. 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 marine animals. 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 organic particles or fragments from their surroundings.

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.