425 Million Year Old Fossil Shows Tongue Worm Attacking Ostracod

Posted on July 11, 2015

Scientists have created a 3D reconstruction of a 425-million-year-old fossil where a parasite is attacking an ostracod. The parasite is an ancient tongue worm and the host species is an ostracod, a group of micro-arthropods that had two shells joined together at a hinge. One of the tongue worms can be seen on the top right outside the ostracod's shell in the above image. This is the only known fossil pentastomid preserved with its host.

The ancient tongue worm has a worm-like body, a head and two pairs of limbs. Modern relatives of the tongue worm live in the respiratory system of host animals, including humans. There are about 140 known species of tongue worms or pentastomids living today. The ancient tongue worm species has been named Invavita piratica, which means ancient intruder and piracy. The parasites ranged in size from 1 to 4 millimeters.

The well-preserved fossil was discovered in in Herefordshire, England. The tongue worms in the fossil were attacking the ostracod on the inside of its shell as well as the outside. One was found near its eggs. The image below provides a view of the fossil reconstruction with the shell removed.

Paleontologist David Siveter of the University of Leicester is the lead author of the study. He says, "This discovery is important not only because examples of parasites are exceptionally rare in the fossil record, but also because the possible host of fossil tongue worms - and the origin of the lifestyle of tongue worms - has been the subject of much debate."

A research paper on the newly discovered tongue worm was published here in the journal, Current Biology.

This following image shows the ancient tongue worm attack with the shell removed so you can see tongue worm (orange colored) that was inside the ostracod's shell.

ANIMALS