Unknown to science before 2006, the mysterious ghost slug (Selenochlamys ysbrada) was first discovered in a Caerphilly Lane. In May 2009 it was named as one of the 'top new species described' in 2008 by the International Institute for Species Exploration.
A Cardiff gardener found a specimen in 2007. Other examples have been found around Swansea.
The ghost slug is carniverous and nocturnal, sucking earthworms into its body with blade-like teeth. Although similar species exist in eastern Europe, the Welsh examlpes have been classified as a wholly new species, being given the name ysbryda from the Welsh for ghost.
The ancestor individuals' route to Wales can only be speculated on, but Bill Symondson of Cardiff University believes they may have come in on pot plants.
Spending most of its time underground, it squeezes its flexible body into cracks or tunnels to get at earthworms, which it detects by smell or taste.
The slug population is being monitored in case it becomes a pest species.
Photo courtesy of Amgueddfa Cymru - National Museum Wales.
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