The Mardy Monster

Fast Facts

Latin name: Turdulisoma cf helenreadae

Notable feature: The Mardy Monster is a brown millipede, about 12mm in length. It’s body has distinctive, bluntly rounded extensions of its exoskeleton.

Conservation Status: Not Evaluated

Where in the UK: Known from a single UK site - the former Mardy Colliery in the village of Maerdy, Rhondda Cynon Taf, South Wales.

The Mardy Monster (Turdulisoma cf helenreadae) © Liam Olds

The Mardy Monster is a ‘New to Science’ millipede found by Christian Owen at Mardy Colliery in December 2016. The first specimens were discovered under an old railway sleeper, with more individuals found beneath stones on sparsely vegetated banks of colliery spoil.

A brown millipede, about 12mm in length, with each eye having about 25 ommatidia in the shape of an equilateral triangle. It is very difficult to distinguish between other new species of millipede found in recent years in South Wales.

Globally, this species has only been found at the former Mardy Colliery, Maerdy, Rhondda Cynon Taf, South Wales. It’s not known if the Mardy Monster is native to the UK and was overlooked or it was introduced.


  • Size: 12mm in length.
  • Life span: Unknown.
  • Diet: Most likely feeds on algae from deadwood.
  • Reproduction: Unknown.
  • When to see: Winter
  • Population Trend: Unknown as it is found on this one site and no work has been undertaken to ascertain its abundance/distribution on this site.
  • Threats: The main threat to this species is development, with the premise of a solar farm being the latest development proposal for the site. The site also suffers from illegal off-road activities which damage habitat.
  • Fun Fact: The millepede was named after the Mardy Monster locomotive utilised at Mardy Colliery. The locomotive was built by Peckett & Sons in 1954 and, based on tractive effort, it is the most powerful steam locomotive design built in Britain. The locomotive was withdrawn from industrial service in 1976.

How you can help:

Buglife is working to increase awareness of invertebrates and the Beddau Beast through specific projects, such as Coil Spoil Connections, but we need your help! Visit the project page to find out how you can get involved in events and BioBlitz’s. This species was found during a bioblitz at the Mardy Colliery site so who knows what other species are out there waiting to be discovered!

Join a recording scheme and log your finds – download the iRecord app and get recording!


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