LAUSR

The Antarctic nematode Panagrolaimus davidi can survive intracellular freezing. Genetic studies indicate the culture strain (now designated as Panagrolaimus sp. DAW1) is a different species to the P. davidi of field origin. This paper reports further attempts both to isolate DAW1 from Antarctic soils and to culture P. davidi itself. Sequencing of the 18S rRNA gene of 151 individuals indicates that DAW1 is rare in the field, but characterising two new isolates shows that, nevertheless, it is present. Panagrolaimus davidi is common in the field, but cannot be cultured using the media tested here. These two species are difficult to distinguish morphologically, apart from the absence of males in DAW1 and its longer recurved tail. Whilst it is possible that DAW1 is an introduced species, the sites at Shackleton’s hut at Cape Royds are dominated by P. davidi , which is clearly an endemic species.