Elaphoidella stygobiotica (Copepoda: Harpacticoida: Canthocamptidae), a new species of cave-dwelling copepod from western Thailand

A sampling campaign of cave-dwelling copepods between 2016 and 2022 in Thailand resulted in the discovery of a new Elaphoidella species found in the Lawa cave. The cave is located in the Tenasserim Hills within Kanchanaburi Province in the western part of Thailand. The new species has been found exclusively in that location and therefore appears to be endemic to the region. The new species has been assigned to group X proposed by Lang (1948) and can be distinguished from three other species within the group present in Southeast (SE) Asia, namely E. elegans, E. cornuta, and E. javaensis, based on several morphological characteristics. The most similar species within the genus is E. elegans from Java, Indonesia, but they differ in ornamentation of the urosomites and armature of the antennae and legs. The other SE Asian species within group X are also compared and differentiated.