We used molecular and morphological techniques to study troglobitic schizomids inhabiting a variety of subterranean landforms in semiarid Western Australia. The study was designed to explore the taxonomic and phylogenetic status of newly discovered populations of subterranean schizomids. Molecular sequences of the mitochondrial DNA (mtDNA) cytochrome oxidase subunit 1 (COI) and small subunit rRNA (12S) were obtained from a total of 73 schizomid specimens. Populations sampled from boreholes within mesa landforms in the Robe Valley were highly genetically distinct from species of Draculoides Harvey, 1992 found elsewhere in the Pilbara (Cape Range and Barrow Island). Pronounced genetic structuring was also evident at a fine spatial scale within the Robe Valley, with populations from each of the mesas examined exhibiting unique and highly divergent mtDNA lineages. These molecular data were generally supported by small but significant morphological features, usually in the secondary male structures, but some species were represented only by female specimens that possessed more conservative morphologies. The molecular data defined two major in-group clades, which were supported by morphological differences. One clade was widespread and included the type species of Draculoides, D. vinei (Harvey), along with D. bramstokeri Harvey & Humphreys, D. brooksi Harvey, D. julianneae Harvey, D. mesozeirus, sp. nov. and D. neoanthropus, sp. nov. The second clade was restricted to the Robe Valley and deemed to represent a new genus, Paradraculoides, which included four new species P. anachoretus, sp. nov., P. bythius, sp. nov., P. gnophicola, sp. nov. and P. kryptus, sp. nov. (type species).

A review of the Australian endemic millipede genus Atelomastix reveals the presence of 28 species, including the type species A. albanyensis Attems, A. nigrescens Attems, and 25 new species from Western Australia, as well as A. solitaria Jeekel from Victoria. All species are from the high rainfall zone of southern Australia. The new species are: A. anancita, A. attemsi, A. bamfordi, A. brennani, A. culleni, A. danksi, A. dendritica, A. ellenae, A. flavognatha, A. francesae, A. gibsoni, A. grandis, A. julianneae, A. lengae, A. longbottomi, A. mainae, A. melindae, A. montana, A. poustiei, A. priona, A. psittacina, A. rubricephala, A. sarahae, A. tigrina and A. tumula. Most species are shown to have extremely small distributions and all are classified as short-range endemic species. Most species have been collected at very few locations, occurring in discontinuous habitats such as mountain ranges, islands, granite outcrops, or fragments of wet forest.

We studied a variety of chthoniid pseudoscorpions collected from the semiarid zone of Western Australia. Five new species of Tyrannochthonius Chamberlin, 1929 and three new species of Lagynochthonius Beier, 1951 are named and described from the Pilbara and Gasgoyne regions, and surrounding areas such as Barrow Island. Tyrannochthonius basme, sp. nov. and Lagynochthonius asema, sp. nov. from pisolitic mesas near Pannawonica, T. garthhumphreysi, sp. nov. from limestone karst on Barrow Island, T. souchomalus, sp. nov. from calcrete deposits near Cue, T. billhumphreysi, sp. nov. and L. polydentatus, sp. nov. from a calcrete deposit on Sturt Meadows Station and L. leemouldi, sp. nov. from calcrete near Marble Bar are all considered to represent hypogean species as all exhibit typical troglomorphic adaptations including total loss of eyes and attenuated appendages. New records are provided for T. brooksi Harvey and T. butleri Harvey from Cape Range peninsula. A new epigean species, T. aridus, sp. nov., was found on Barrow Island and the Pilbara mainland. Two further putative new species based upon nymphal specimens from subterranean environments are described but not named owing to the lack of adult specimens. Although the epigean species T. aridus, sp. nov. is relatively widespread, all of the subterranean species are thought to represent short-range endemic species as they have been found at very few locations, all of which occur in localised habitats such as limestone or within mesa formations. Tyrannochthonius chamorro Chamberlin, 1947 from Guam is transferred to the genus Lagynochthonius, creating the new combination Lagynochthonius chamorro (Chamberlin 1947).