An antarctic biogeographical anomaly resolved: the true identity of a widespread species of Collembola

摘要

Springtails and mites are the most abundant and species rich micro arthropods in the Antarctic and species tend to be short-range endemics. It was thought that the Springtail (Collembola), Friesea grisea (Schaffer) was an exception. It was described briefly nearly 150 years ago from South Georgia and has not been redescribed from the type locality since. However, published localities include the South Shetland Islands, the Antarctic Peninsula, Enderby Land, Marguerite Bay and South and North Victoria Land suggesting that it is unusually widespread. Recent sequence data have indicated that some Antarctic populations could be putative species but individuals were allegedly morphologically identical. No sequence data were available for South Georgian specimens. These results suggested that a new examination of the South Georgian species' morphology was needed in order to resolve the anomalous biogeographic patterns. I here redescribe F. grisea from South Georgia and show that it has subtle morphological characters that distinguish it from Antarctic individuals allowing it to be unambiguously distinguished from all known Antarctic populations. Consequently, Friesea antarctica is taken out of synonymy with F. grisea. These results emphasise the endemism of Antarctic faunas and allows more targeted conservation planning, especially for short-range endemic species located in likely refugia during glacial periods. Descriptions of putative species from the Continental populations are currently in progress. A new Friesea species from South Georgia, F. fantaba, is also described here. The genus Friesea is now the most species-rich genus of terrestrial arthropods in both the Antarctic and subantarctic and includes twelve species.