Preliminary notes on the Cavernicolous Arthropod Fauna of Judbarra/Gregory Karst Area, northern Australia

Abstract

The Judbarra / Gregory Karst Region is situated in the Judbarra / Gregory National Park, west of Timber Creek, Northern Territory. Several large joint controlled maze caves occur within the area, developed within and below a prominent dolomitic layer (the Supplejack Member). The caves are predominantly shallow in depth (< 15 m below the surface) but are occasionally developed deeper as multi-level systems, reaching the aquifer. Two biological surveys from the largest caves have revealed 56 morphospecies from 43 families, 19 orders, and 7 classes. All collecting was undertaken in the northern dry season (April to September) and consisted predominantly of opportunistic collecting. The diversity of invertebrates collected from the Judbarra / Gregory karst comprised non-troglobionts (48 species, 86%), troglobionts (5 species, 9%), stygobionts (2 species, 3%), and trogloxenes (1 species, 2%). Five of the species are considered to be potential troglobionts, and two potential stygobionts as indicated by troglomorphisms such as elongate appendages and reduced or absent eyes. The five troglobiont species are an isopod (Platyarthridae: Trichorhina sp.), a scorpion (Buthidae: Lychas? sp. nov.), a pseudoscorpion (Geogarypidae: Geogarypus sp. nov.), a millipede (Polydesmida: sp.), and a planthopper (Meenoplidae: sp.). The two stygobiont species are a hydrobiid snail (Hydrobiidae: sp.), and an amphipod (Amphipoda: sp.). The troglobiont scorpion is only the second collected from a cave environment from continental Australia.