Systematics of Haloniscus Chilton, 1920 (Isopoda: Oniscidea: Philosciidae), with description of four new species from threatened Great Artesian Basin springs in South Australia

Abstract

Recent surveys of Australian arid-zone groundwater ecosystems have uncovered considerable species diversity and extreme endemism for the oniscidean isopod genus Haloniscus Chilton, 1920. Phylogenetic and species delimitation analyses have recognised several distinct species from the Great Artesian Basin springs in South Australia, inspiring a morphological reassessment of the genus and examination of specimens from the iconic Lake Eyre and Dalhousie Springs. We present a revised diagnosis of Haloniscus, transfer the genus from the family Scyphacidae to Philosciidae and describe four new species, H. fontanus Stringer, King & Taiti n. sp., H. microphthalmus Stringer, King & Taiti n. sp., H. rotundus Stringer, King & Taiti n. sp., and H. yardiyaensis Stringer, King & Taiti n. sp., based on combined morphological and molecular evidence. We compare the results of molecular-based species delimitation analyses with morphological data, provide distribution information, and present a key to the described species of Haloniscus. Two species presently included in Andricophiloscia Vandel, 1973, A. stepheni (Nicholls & Barnes, 1926) and A. pedisetosa Taiti & Humphreys, 2001, from Western Australia are also transferred to Haloniscus.