, or Alcathoe's bat, was identified by a research team led by Professor John Altringham at the University of Leeds and Professor Roger Butlin of the University of Sheffield during a Europe-wide study of bat population ecology and genetics.
Alcathoe's bat - which is about the size of the end of a person's thumb - was 'discovered' in Greece in 2001 and is a native of continental Europe. But until now, it was presumed that the English Channel acted as a barrier which had prevented it reaching the UK.
In Yorkshire the bats were found in a Forestry Commission woodland in Ryedale in the North York Moors National Park, a biologically rich site that was home to the north of England's last known colonies of rare barbastelle and lesser horseshoe bats over 50 years ago.
The southern sites are in the South Downs of Sussex, a wooded area known for a number of rare woodland bat species. Alcathoe's bat may well be present in many other parts of the country.
The researchers believe the bat is actually resident in the UK but has not been spotted before because its appearance is so similar to other bat species.
Professor Altringham said: "Over a third of the UK's native land mammal species are bats, making them by far the biggest contributor to our mammalian diversity. This discovery takes the number of bat species established in the UK from 16 to 17. Most of the bats were captured as they entered underground "swarming" sites, where bats gather to mate before going into hibernation. A single swarming site, usually a cave or disused mine, can attract thousands of bats of ten or more species. This makes them good places to look for rare species.
"Its presence at sites 350 km apart suggests that Alcathoe's bat is a well-established, resident species. Preliminary evidence suggests that it makes up a significant proportion of the small Myotis bats at both the Yorkshire and Sussex sites. Its close resemblance to two other UK species means it has gone unnoticed."
Professor Butlin said: " Our genetic analysis* (mitochondrial and nuclear DNA) places Alcathoe's bat as a very close relative to the whiskered bat (M. mystacinus) a widespread but relatively uncommon UK species. These two species and a third, Brandt's bat (M. brandtii), are so similar in appearance that identification based on appearance alone can be difficult even for the unwary expert."
Prof Altringham added: "However, Alcathoe's distinctive echolocation call, which terminates at a significantly higher frequency than those of its relatives (43-46 kHz), alongside some subtle physical differences makes identification possible without genetic analysis.
"Although similar in appearance these three bats may prove to be ecologically quite different. The separation of the common pipistrelle into two species in the 1990s led to the discovery that despite their physical similarity they have significantly different roosting habits, feeding habitat and food."
Brian Walker, Forestry Commission Wildlife Officer for the North York Moors, said: "We have some incredibly rich bat habitats in North Yorkshire and it was only a few years ago that work locally helped to confirm that the common pipistrelle was actually made up of two different species. The discovery of Alcathoe's bat is another first to add to the record books."
Photo credits: Cyril Schönbächler
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