The tongue worm parasite (orange) is attached to the host ostracod. (David Siveter)

CBC Radio’s Quirks & Quarks has another interesting segment.  This one is about a 425 million year old parasite, a tongue worm, found attached to its host.  The host is an ostracod, which is a type of crustacean.  It was discovered in Herefordshire, England and is the first fossil of its kind.  The paper appeared in the journal Current Biology.

Dr. David Siveter, Emeritus Professor of Paleontology at the University of Leicester, studied the fossil and discovered three tongue worms – one inside attached to eggs and two on the outside of the crustacean’s shell.

Because the fossil was found in an ancient marine environment, it indicates that the tongue worm made the transition to a land animal parasite at some point. The many species of tongue worm today are parasites of reptiles, snakes and humans.