Pseudoscorpions of the family Feaellidae (Pseudoscorpiones : Feaelloidea) from the Pilbara region of Western Australia show extreme short-range endemism Mark S. Harvey A,B,C,D,F , Kym M. Abrams A,B , Amber S. Beavis A,E , Mia J. Hillyer A and Joel A. Huey A,B A Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, WA 6986, Australia. B School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia. C School of Natural Sciences, Edith Cowan University, Joondalup, WA 6027, Australia. D Division of Invertebrate Zoology, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024-5192, USA; Department of Entomology, California Academy of Sciences, Golden Gate Park, San Francisco, CA 94103-3009, USA. E Present address: Office of the Chief Scientist, Industry House, 10 Binara Street, Canberra City, ACT 2601, Australia. F Corresponding author. Email: mark.harvey@museum.wa.gov.au Abstract. The phylogenetic relationships of the Australian species of Feaellidae are assessed with a molecular analysis using mitochondrial (CO1) and nuclear (ITS2) data. These results confirm the morphological analysis that three previously undescribed species occur in the Pilbara bioregion, which are named and described: Feaella (Tetrafeaella) callani, sp. nov., F. (T.) linetteae, sp. nov. and F. (T.) tealei, sp. nov. The males of these three species, as well as males of F. anderseni Harvey and other unnamed species from the Kimberley region of north-western Australia, have a pair of enlarged, thick-walled bursa that are not found in other feaellids. Despite numerous environmental impact surveys for short-range endemic invertebrates in the Pilbara, very few specimens have been collected, presumably due to their relictual distributions, restricted habitat preferences and low densities. http://zoobank.org/urn:lsid:zoobank.org:pub:131F0587-F2EE-405F-BE5A-772F072D9915 Additional keywords: morphology, new species, taxonomy, threatened species. Received 12 February 2016, accepted 27 April 2016, published online 31 October 2016 Introduction With only a handful of named species, the Feaellidae are one of the smallest pseudoscorpion families, surpassed only by Pseudogarypidae with seven recent species and the monotypic Parahyidae (Harvey 2013). Feaellids have arguably the most unusual body shape of any pseudoscorpion, with short raptorial pedipalps and a highly thickened femur, a strongly rounded abdomen and deeply lobed anterior margin of the carapace (Figs 7, 18, 32, 33). Along with Pseudogarypidae, they belong to the superfamily Feaelloidea (e.g. Chamberlin 1931; Harvey 1992). Opinions on the relationships of the feaelloids have varied since they were first described, and they have been placed between the Garypidae and Cheliferidae in the Panctenodactyli by With (1906), as a member of the suborder Monosphyronida by Chamberlin (1931) and in the suborder Neobisiinea (roughly equivalent with Chamberlin’s Diplosphyronida) by Beier (1932). Weygoldt (1969: 129) summarised the dilemma posed by some of the morphological features found in feaellids, stating ‘it seems that they are an old family that originated either close to the Heterosphyronida or somewhere between Heterosphyronida and Diplosphyronida. They should be considered, perhaps, as a separate suborder, but further taxonomic work is necessary before this question can be settled’. Harvey (1992) found feaelloids to group with the superfamily Chthonioidea, which together formed the suborder Epiocheirata, whereas in molecular analyses using three mitochondrial and nuclear genes, Murienne et al.(2008) recovered feaelloids as the sister-group to all other pseudoscorpions, and Arabi et al.(2012) found them to be sister to Iocheirata. Journal Compilation Ó CSIRO 2016 www.publish.csiro.au/journals/is CSIRO PUBLISHING Invertebrate Systematics, 2016, 30, 491–508 http://dx.doi.org/10.1071/IS16013