Scientists find new fossilised English species of parasitic tongue worm

This article originally appeared on Culture24.

A 420 million year old species of  tongue worm parasite has been discovered still attached to the shell of its host

A new fossil species found in 425-million-year-old rocks in Herefordshire has been identified by scientists as an ancient parasitic intruder.

Several examples of the species - a type of 'tongue worm' with a soft body ranging from 1 to 4 millimetres - have been identified in the fossils, which scientists describe as exceptionally well preserved.

The species has a worm-like body, head and two pairs of limbs. Its descendants today live in the respiratory system of a host when eaten.

The ancient fosillised version of the grisly parasite was found still attached to its unfortunate host, a species of ostracod (a small sea creature) with two shells joined at a hinge.

Despite their name, tongue worms (technically termed pentastomids) are not worms at all but rather an unusual group of tiny and widespread parasitic arthropods. Today there are approximately 140 species of them and they can affect vertebrate animals, particularly reptiles and even humans.

Their fossils are exceptionally rare and until now are known only from a handful of isolated juvenile specimens.

Professor David Siveter of Leicester University, who made the discovery with colleagues from various universities across Europe, described the fossilised discovery as “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”.

“This discovery affirms that tongue worms were ‘external’ parasites on marine invertebrate animals at least 425 million years ago,” he added.

“It also suggests that tongue worms likely found their way into land-based environments and associated hosts in parallel with the movement of vertebrates onto the land by some 125 million years later.”

The tongue worm and its host lived in a sea, which 425 million years ago during the Silurian period of geological time would have covered much of southern Britain, then positioned in warm southerly subtropical latitudes.

Scientists have reconstructed the fossils using 3D computer modelling and named the new species Invavita piratica, which means an ‘ancient intruder’ and ‘piracy’, referring to its parasitic lifestyle in the sea.  

The research has been published in the journal Current Biology and was supported by The Natural Environmental Research Council, together with the Leverhulme Trust, the John Fell Oxford University Press (OUP) Research Fund and Yale Peabody Museum of Natural History.

What do you think? Leave a comment below.

More from Culture24's Dinosaurs and Fossils section:

"A crucial transformation": Scientists use 500 million-year-old fossilised brain to study evolution of animal heads

Penis Worm was a fearsome Cambrian period predator with teeth like a cheese grater, say palaeontologists

Huge lobster-like animal filtered seawater for food 480 million years ago, say fossil hunters

Source: http://www.culture24.org.uk/science-and-nature/dinosaurs-and-fossils/art527328-scientists-find-a-new-fossilised-english-species-of-parasitic-tongue-worm