Drepanocladus longifolius

Ronikier, Marta Saługa Ryszard Ochyra Jan Żarnowiec Michał, 2018, Do Antarctic populations represent local or widespread phylogenetic and ecological lineages? Complicated fate of bipolar moss concepts with Drepanocladus longifolius as a case study, Organisms Diversity & Evolution 18 (3), pp. 263-278 : 265

Drepanocladus longifolius — recent colonist or in situ survivor?

Contemporary Antarctic populations of D. longifolius are known exclusively from the maritime Antarctic ( Ochyra et al. 2008a; Li et al. 2009). The recent origin of the Antarctic populations may be supported by occurrence of this species on sub-Antarctic islands and on neighbouring lands of South America and Australia. Moreover, sub-fossil findings in the Admiralty Bay area on King George Island, dated to 4950 B.P., also point to recent colonisation of this moss species ( Birkenmajer et al. 1985).

On the other hand, aquatic forms of Drepanocladus longifolius from the Antarctic differ considerably from non- Antarctic populations. Antarctic forms of D. longifolius are apparently unique amongst other aquatic mosses in being submerged in water of lakes ( Li et al. 2009). Moreover, it has never been reported on ground around the lakes, whereas other mosses are land forms which have become adapted to the aquatic environment. In contrast, plants from South American mainland and Tierra del Fuego usually thrive in swampy habitats and are seldom submerged in pools and streams. Being permanently submerged in deepwater results in admittedly different morphology. Aquatic mosses significantly differ from their terrestrial counterparts in size and shape of the leaves ( Priddle 1979). Accordingly, Antarctic forms have straight, narrowly lanceolate and long-acuminate leaves, whereas the South American plants have predominantly strongly falcato-secund leaves ( Ochyra et al. 2008a; Li et al. 2009).

Due to the morphological variability between the plants of Drepanocladus longifolius from the maritime Antarctic and South America, we are particularly interested in the origin, colonisation history and the degree to which Antarctic populations are genetically isolated from those in other Southern Hemisphere landmasses.