“…Accordingly, he characterised the organisms inhabiting the psammon as psammobiontic, those organisms that live exclusively, except fortuitously, in the psammon; psammophile, those that show a clear preference for the psammon, but which may also be found in the littoral; and psammoxene, those that avoid the psammon (Wiszniewski, 1937). Notwithstanding that there is a substantial body of recent literature on psammon and interstitial habitats in lotic (Schmid-Araya, 1995, 1998Turner, 1996) as well as in lentic freshwater environments (Wiszniewski, 1934a(Wiszniewski, , 1934bMyers, 1936;Pennak, 1939;Bielańska-Grajner, 2001Radwan & Bielańska-Grajner, 2001;Ejsmont-Karabin, 2004), there are particularly few studies on these habitats in (sub)tropical regions. Recently, Segers and Chittapun (2001) reported on a limited collection of interstitial rotifers from a peat swamp on Phuket Island, Thailand, and described three new rotifer species, viz.…”