The riddle of the mystery gazelle
From chimera to species: Museum specimens obtained nearly 200 years ago represent the only evidence for an enigmatic species of Arabian gazelle. Closer examination of the material has now led to a different, and very surprising, conclusion.
Photo: Torsten Wronksi
Protection of biodiversity requires detailed knowledge of individual species and their geographical distributions. In addition to direct observations in the wild, the collections held by museums of natural history provide valuable information in this context. However, one sometimes comes across museum specimens collected long ago which document species that seem to have disappeared soon after they were discovered. One such case concerns the Arabian gazelle (Gazella arabica), which was known only on the basis of museum specimens that arrived from Arabia in Berlin in 1825.
The International Union for Conservation of Nature (IUCN) included G. arabica as an extinct species on its Red List until 2008. Its status was then revised to “data deficient” owing to the lack of genetic data. To remedy this deficiency, LMU researchers recently examined the DNA of the almost 200-year-old type specimen, as part of a collaborative project that also involved scientists from the UK and Saudi Arabia. The results surprised everyone. “It turned out that the skin and the skull come from different animals,” says Dr. Gertrud Rößner of the Bavarian State Collection for Paleontology and Geology.
Type specimen unmasked as a chimera
“The combination of elements from different individuals has led zoologists to search for a species that never existed,” says Eva Bärmann, a doctoral student at Cambridge University, who carried out the intricate DNA analyses at LMU. The results revealed that the specimen is in fact a “composite” made up of parts representing two different lineages of the mountain gazelle (G. gazella) found in the Eastern Mediterranean region and on the Arabian Peninsula, respectively.
But that’s not all. The new data indicate that the Arabian form, hitherto classified as a subspecies of G. gazella and recently recognized as a species in its own right, is in fact G. arabica, alive and kicking. “Our analyses underline the enormous significance of type specimens – not only as objects of historical value, but as indispensable references for studies of biodiversity and efforts to preserve it, even in the era of molecular biology,” says Professor Gert Wörheide of the Department of Earth and Environmental Sciences, in whose laboratory the genetic analyses were performed. (Mammalian Biology, 2012) göd
The study was financed by the Natural Environment Research Council (UK), the Cambridge European Trust and the Balfour Fund (University of Cambridge).