Scientific Publications from the Virginia Museum of Natural History
by Janet W. Reid
published 15 May 2004
Ten species of the cyclopoid copepod crustacean genus Diacyclops were collected by Julian J. Lewis and his associates from caves, wells, and the hyporheic zone of streambeds in karst and non-karst terrain in southern Indiana, USA. These collections included six previously known species: D. crassicaudis brachycercus, D. jeanneli, D. navus, D. nearcticus, D. sororum, and D. yeatmani. Diacyclops jeanneli, which was originally described from Marengo Cave in Crawford County, is redescribed herein. A population of D. jeanneli still exists in Marendo Cave, and other populations were discovered in Floyd, Harrison, and Orange counties. All the sites where D. jeanneli was collected are located in the Blue Ridge faunal basin. Three new species, D. salisae, D. lewisi, and D. indianensis, are described from wells and a cave in Big Oaks National Wildlife Refuge. The refuge lies within the Muscatatuck faunal basin, with was covered by the Illinoian glacier. these three species show few or none of the morphological reductions that are normally associated with the subterranean habitat. They may have invaded subterranean habitats comparatively recently, i.e., after the Illinoian glacier began to retreat about 140,000 years ago. Female cyclopoids that are morphologically identical to D. indianensis were recently discovered in two caves in east-central Tennessee; therefore the primary habitat of D. indianensis may be groundwater rather than caves. Both Diacyclops jeanneli and D. conversus show several reductions that are typical of subterranean cyclopoids, and may be more ancient subterranean inhabitants than D. salisae, D. lewisi, and D. indianensis.