A bat preserved in alcohol for 30 years in the Museum's collection has been recognised as a new species of horseshoe bat.

The female bat was collected in Malaysia in 1983 by Charles M Francis. The new species is named Rhinolophus francisi, or Francis' woolly horseshoe bat, in his honour. As the first example of this new species ever found and described, the Museum specimen has been designated as the type specimen. This means it will be used as a reference point by scientists trying to classify similar bats in the future. 'This new species of bat highlights once more the value and importance of natural history collections,' says Roberto Portela Miguez, an author of the study and Curator of Mammals at the Museum. 'Our current and future understanding of the world's biodiversity depends to a great extent on these collections and those who study them.'

Funny face Bats in the Rhinolophus genus typically have a horseshoe-shaped, leaf-like structure on their nose, earning them the common name 'horseshoe bats'. Experts think that they use this structure to focus the sound of their echolocation calls, which are used for navigation and finding food. Rhinolophus bats use a specially adapted sound frequency to detect fluttering insects.

Field surveys across Southeast Asia, in addition to the re-examination of the Museum specimen, helped a network of researchers to identify the new species, Rhinolophus francisi. The team collected genetic and acoustic data from a range of bats in the region for comparison, and found that some specimens were distinct from any known species. Bat bones are very thin and fragile, so to avoid handling the Museum specimen, the researchers used a CT scanner to measure the key dimensions of the animal's skull.

Two more specimens, collected in central and western Kalimantan in Indonesia in 2004, have also been identified as members of the new species. One is now deposited at the Harrison Institute in the UK, and the other in Indonesia's Museum Zoologicum Bogoriense. Further surveys and analyses of other bats housed in museum collections could show that the species is widespread in Southeast Asia. Genetic data suggest that it may also be present in Vietnam, but the paper's authors say that further confirmation is needed. A fourth specimen, from western Thailand, was found to be almost identical in terms of its physical appearance and echolocation frequencies. But genetic sequencing revealed a genetic divergence of about 10 per cent from the Indonesian specimens, leading the researchers to describe the Thai specimen as a subspecies, Rhinolophus francisi thailandicus. They say that future research in Thailand's forests may reveal that the two populations are sufficiently distinct to consider Rhinolophus francisi thailandicus a new species in its own right. Shrinking forests Unlike fishes, insects and amphibians, the discovery of new mammal species is relatively rare. Bats have been a notable exception to this rule in recent years.