THE FIRST RECORD OF CAVE-DWELLING COPEPODA FROM THAILAND AND DESCRIPTION OF A NEW SPECIES: ELAPHOIDELLA NAMNAOENSIS N. SP. (COPEPODA, HARPACTICOIDA)

During a brief collecting expedition in Nam Nao National Park, Phetchabun province (northern Thailand) in November 2007, various water bodies connected with subterranean water were sampled. In five caves, eight samples were collected from pools and six species of Copepoda were collected. For the first time, a stygobiotic (= cave-dwelling) species of Copepoda was discovered in Thailand. It belongs to the order Harpacticoida and was recognized as a new species, Elaphoidella namnaoensis n. sp. Specimens were only collected from pools filled by percolating water. This indicates a specific ecology of the new species, linked to the unsaturated zone of karstic aquifers, where the hydrology is determined exclusively by rainfall. A detailed description of the new species is presented here, supplemented with some information on its ecology and morphological adaptations. These adaptations are compared to those found in other Elaphoidella species from the unsaturated zone of karstic aquifers in Europe.