Class DIPLOPODA

These are larger animals, variable in appearance but often cylindrical from 2 to 30 mm or more long and with from less than 50 to more than several hundred leg pairs. Their distinctive feature is that most of the apparent trunk segments (diplosegments) bear two pairs of legs. As the animals develop the number of diplosegments and hence of leg pairs increases.

Of the 10,000 or so described species of millipede, four clearly halophilic species are reported from Europe, USA, Far-eastern Russia and Tasmania. In addition, two penicillate or bristly millipedes are also recorded, Polyxenus lapidicola described by Silvestri from the Mediterranean (no subsequent definite records) and a Chilexenus sp. is reported from South Africa by Lawrence (1984).

The total number halophilic diplopod species in the world may be 20 or much more as there are no records at all from western North America, Central & South America and the Caribbean, all of Asia and most of Oceania and littoral diplopods are often difficult to find. Probably there are as yet undescribed, littoral species in collections as well as described species for which no habitat data was recorded at the time.

Other species may occur in supra-littoral sites, some frequently. For instance, Cylindroiulus latestriatus (Curtis, 1845) is characteristically found in such sites all around the coast of Britain and Ireland as well as occurring inland (Lee, 2006).