Four new species of the myrmecophile Diplocotes Westwood (Coleoptera: Ptinidae) from Queensland and South Australia Karen L Bell* and T Keith Philips Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA. Abstract Four new species of the Australian ptinid genus Diplocotes are described. Two of these species are from the dry tropical and subtropical areas of northern and central Queensland, while the other two are from the arid areas of South Australia. While the four new species described here have not been observed with ants in the field, the species of this genus are known to be myrmecophilous, and similar interactions may occur between the new species and their host ants. Additionally, many characters are shared with other unrelated myrmecophilous species, and may be convergent adaptations to the ant-associated lifestyle. Key words central Australia, Diplocotes, myrmecophilous, Ptinidae, spider beetle. INTRODUCTION The spider beetles (Coleoptera: Ptinidae) are a diverse group of beetles, occurring throughout most of the world, and occu- pying a variety of ecological niches, with high levels of diver- sity in arid habitats. There are roughly 700 species placed within 75 genera and currently most species are known from the southern Holarctic region and southern Africa. The Australian endemic tribe Ectrephini is myrmecophilous and wingless. It is a highly derived lineage, with a high species richness in the arid and semi-arid areas of central Australia. There are four genera of Ectrephini – Diplocotes Westwood, Polyplocotes Westwood, Ectrephes Pascoe and Enasiba Olliff – containing 35 described species (Lawrence & Reichardt 1969). Lawrence and Reichardt (1969) considered all four genera to be derived from a single ancestor based on several hypothesised synapomorphies. The huge diversity of forms within the Ectrephini has meant that many species were originally described in monotypic genera, often diagnosed solely by differences in antennal mor- phology. Lawrence and Reichardt (1969) noted a lack of cor- relation of antennal morphologies with other characters, and considered antennal modifications to be adaptive, noting simi- larities to unrelated myrmecophilous Coleoptera. Accordingly, they redefined the genera based on other characters, reducing the number of genera in the tribe from 14 to 4, but did not undertake any generic revisions nor produce a phylogeny sup- porting the monophyly of each group. They placed 19 species in the genus Diplocotes, with the most consistent characters grouping the species based on the clypeus, and the absence of unique characters of the pronotum that define the genera Poly- plocotes, Ectrephes and Enasiba. The majority of described species of Diplocotes are recorded from southern and western Australia, with the fauna of the south-west being distinctly different and more diverse than the fauna of the south-east and north-west (Lawrence & Reichardt 1969). The north-eastern Australian fauna (New South Wales, Queensland and Northern Terri- tory) is less diverse, although this may be an artefact of col- lecting effort. Here we describe two recently collected species from this less speciose north-eastern region, and two new species from the more species-rich region of central Australia. We currently consider the spider beetles as a family rather than a subfamily of the Anobiidae due to the possibility that they should both be subfamilies of the Bostrichidae. Both are derived clades of the bostrichids (Ivie 1985; Philips 2000), and excluding them from this group results in a paraphyletic Bos- trichidae. There is also morphological (Philips 2000) and molecular evidence (KL Bell and TK Philips, unpubl. 2007) that the spider beetles are sister to the anobiids rather than a derived clade of the latter. Lastly, based on priority of names, one could consider the anobiids to be more correctly called Ptinidae. We hope to rectify this semantic situation in the near future. MATERIALS AND METHODS Specimens were borrowed from the South Australian Museum, Queensland Museum and Canadian Museum of Nature. Specimens were examined under fibre optic and fluo- rescent light using a Leica MZ-16 microscope. Photographs were taken using an auto montage system from Syncroscopy *Present address: CSIRO Entomology, 120 Meiers Road, Indooroop- illy, Qld 4068, Australia (karen.bell@csiro.au). Australian Journal of Entomology (2008) 47, 80–86 © 2008 The Authors Journal compilation © 2008 Australian Entomological Society doi:10.1111/j.1440-6055.2008.00633.x