10 new species of freshwater earthworms

Scientists have discovered 10 new species of semi-aquatic freshwater earthworms in river systems in Thailand.

According to a report published in the journal "ZooKeys", the earthworms in the genus Glyphidrilus occur in a wide range of natural freshwater habitats which include rice fields, where they might play an important role in the development of organic farming.

The newly-discovered worms have a rounded body tip, while the end is square shaped. When twisted, the posterior end, which is normally above the soil surface, forms U-shaped channels. These are used to allow water circulation down the burrow.

This is probably an evolutionary adjustment that ensures oxygen transport to the deeper surface of the worms, while their bodies remain in the burrows.

Another peculiar feature are the so-called “wings”, or the expanded part of epidermis near the body tip. The function of the wings is still unknown to scientists, but it has been suggested that they evolved to assist breathing in such aquatic habitats.