RECORDS OF THE WESTERN AUSTRALIAN MUSEUM 29 105–127 (2014) DOI: 10.18195/issn.0312-3162.29(2).2014.105-127 New species of subterranean silverfi sh (Zygentoma: Nicoletiidae: Atelurinae) from Western Australia’s semi-arid Pilbara region Graeme B. Smith1,2* and Jane M. McRae3 1 Australian Museum, 6 College St, Sydney, New South Wales 2010, Australia. 2 Federation University Australia, PO Box 663, Ballarat, Victoria 3353, Australia. 3 Bennelongia Pty Ltd, 5 Bishop St, Jolimont, Western Australia 6014, Australia. * Author for correspondence. Email: [email protected] ABSTRACT – Three new species of the usually inquiline Atopatelurini, collected deep within iron- ore formations via mining bore holes, are described. Two species, Dodecastyla crypta sp. nov. and D. rima sp. nov. are placed in the Chilean genus Dodecastyla Paclt although certain ambiguities still exist regarding this genus. Troglotheus gen. nov. is erected for inclusion of T. bifurcus sp. nov. due to the absence of dorsal tergal chaetotaxy. Habitat data and possible host associations are discussed. KEYWORDS: hypogean, troglophile, inquiline, iron-ore formations INTRODUCTION cases highly modifi ed terminalia, particularly in the Silverfi sh of the family Nicoletiidae are well known males. Other atelurin species seem to be quite fl exible from subterranean habitats. With the exception of the in their host associations and do not display the more Atelurinae, the members of this family are elongate, extreme morphological adaptations. They can often be primitively eyeless and generally lack pigmentation. found in soil without any obvious host although they While about half of all described non-atelurin species are usually not regarded as hypogean silverfi sh. On have been found in soil related habitats (in humus or two occasions, however, one of us (Smith) has observed under rocks), the remainder have been collected from unidentified atelurins travelling with lines of ants within limestone caves (e.g. Mendes 1994) or from lava deep within caves (Cape Range, WA and Undara, Qld) tubes (e.g. Espinasa and Espinasa Closas 2006, Smith and on another occasion (also at Undara) high density 2006). Cave-adapted forms are often quite spindly with populations (c. 30/m2) of Pseudogastrotheus sp. were longer legs and sensory appendages. In recent years, sampled from the muddy fl oor of a lava tube without any biological survey work for mining companies in Western obvious ant presence. This paper describes three new Australia has seen the sampling of fauna deep within species of Atelurinae that have been collected from deep various rock strata via drilled geological exploration within rock formations via exploratory drill holes in the holes. This has revealed a rich and highly adapted central part of the semi-arid Pilbara region of Western subterranean fauna (e.g. Guzik et al. 2010, Halse and Australia. Pearson 2014) consisting mostly of short range endemic The subfamily Atelurinae is quite diverse with some species, restricted sometimes to a single outcrop. Smith 70 described genera, many of which are monotypic. et al. (2012) described silverfi sh species of the subfamily Mendes (2012) divides the subfamily into fi ve tribes, Subnicoletiinae sampled via such exploration holes in placing all described Australian species within the banded iron formations from the northern part of the Atopatelurini, a tribe characterised by the absence of Pilbara region in Western Australia. scales on the head, the presence of a fovea but the lack of The Atelurinae, once considered as an independent antennal apophyses on the pedicel of mature males, well family (e.g. Watson 1970) but now treated as a subfamily developed molar regions of the mandibles, a galea with within the Nicoletiidae, are considered as specialised just one apical conule, legs with lyriform spines, the lack for a living as inquilines or ‘tolerated guests’ of ants of specialised armature on the median dorsal appendage or termites. Many species, especially those hosted by of mature males, pseudovesicles on urosternite VII and termites, display striking morphological adaptations. the presence of 1+1 vesicles on urosternite VI which These include a much more convex dorsum, a round have a medial tuft of well developed setae. The tribe has or tear-drop shape and reduced appendage lengths, a wide distribution with species described from Africa especially of the terminal fi laments, and in extreme and the Middle East, South Asia, Indonesia, Papua-New http://www.zoobank.org/urn:lsid:zoobank.org:pub:FC516109-8064-4C28-99B0-E123C49599CD 106 G.B. SMITH AND J.M. MCRAE Guinea, New Zealand, South America and Australia. MATERIALS AND METHODS Hosts include termites of the families Mastotermitidae, Termitidae and Rhinotermitidae as well as ants ABBREVIATIONS (Formicidae). I–X abdominal segments from anterior to The Australian atelurin fauna is not well documented posterior are numbered with roman with only nine species having been described, despite numerals many more being represented in various entomological HW head width (always in millimetres) collections. References to the genus Atelurodes Silvestri, H+B head and body length 1916 in Australia (e.g. Smith 1998a), following the lead of Wygodzinsky (1963), are incorrect. Atelura similata juv. juvenile Silvestri, 1908 with fi ve pairs of abdominal stylets, L/W length to width ratio requires redescription and will probably be placed My million years within a new genus near Pseudogastrotheus Mendes, N, S, E, W compass directions north, south, east, 2003 (with only four pairs of stylets). west (often in combination) This paper describes three new species from the PI, PII, PIII prothoracic, mesothoracic and Pilbara with six pairs of stylets, which along with other metathoracic legs respectively characters, appears to place them in or near the genus Dodecastyla Paclt, 1974 erected for the Chilean species PVC polyvinyl chloride (plastic) Lepismina bifi da Schäffer, 1897. Two of the three species will be placed, at least provisionally, in Dodecastyla TERMINOLOGY Paclt. A new genus will be erected for the third species Left and right are used in respect to the animal’s left or owing to its very different head and dorsal chaetotaxy. right side when viewed from above with the head forward. This position may need to be revised when more A new term will also be introduced in this paper for a information becomes available on the chaetotaxy of the type of tergal seta or macrochaeta common within the head and the presence of pulvilli in Dodecastyla bifi da. Atopatelurini. The shape of the individual macrochaetae can be quite signifi cant for the Zygentoma and the term ‘apically bifi d’ is used to describe a wide variety of forms, from quite delicate splits at the very apex, through the strong lyriform spines found on the legs of many atelurin species such as Atopatelura furcifera Silvestri, 1908 or Ausallatelura ordoarmata Smith, 2007 to the antennal macrochaetae of Crypturelloides mindeni Smith and Veera Singham, 2011, which are quite long yet bifurcated for up to ⅔ of their length. Several genera, including Australiatelura Mendes, 1995 and Dodecastyla display fl attened bifurcated setae along the posterior margins of the thoracic and abdominal tergites (Figure 1). In his redescription of Dodecastyla bifi da (as Grassiella bifi da) Silvestri (1905) describes these macrochaetae as short deeply apically incised scales ‘Thorax et abdomen tergites squamis brevibus, latiusculis in apice sat profunde incisis’ and for Australiatelura tasmanica (Silvestri, 1949) describes them as a transverse row of short, robust, apically incised setae ‘serie transversali setarum robustarum brevium, in apice incisarum’. Mendes (1986) describes these as spathulate setae with a profound apical incision ‘sedas espatuladas e com incisão apical profunda’. Stach (1935) commented that these setae resembled fi r needles ‘Diese Borsten errinern sehr an die Nadeln einer Tanne; die sind also zugefl acht, an der Spitze seicht gespalten und haben einer Mittelrippe’. The Latin word for fi r is ‘abies’ which also forms the generic name for trees such as the Silver Fir (Abies alba Miller, 1768), which have needles that bear some resemblence to these fl attened setae. Taking the lead from Stach, we would like FIGURE 1 Australiatelura tasmanica (Silvestri, 1949): to propose the use of the term ‘abiesiform’ to describe this scanning electron micrograph of abiesiform distinct form of macrochaeta while recognising that there macrochaeta with small setula to the upper will be a degree of transition between the various types of right of it, above a typical scale insertion. macrochaetae. NEW TROGLOPHILIC ATELURINAE FROM THE PILBARA 107 STUDY AREA The Pilbara region in north-western Australian has been emergent for up to 3.5 billion years (Buick et al. 1995) and has experienced a range of climates. At the end of the Oligocene, the climate was temperate and the region supported small patches of rainforest. Aridity increased in the mid-Miocene (Macphail and Stone 2004, Martin 2006) and it is likely that some ground- dwelling invertebrates began moving underground in the late Miocene or early Pliocene to escape the drying conditions. Although the major elements of the Pilbara’s current climate came into place about 0.5 My ago, aridity has continued to increase (Martin 2006). The Pilbara now has a semi-arid climate and mostly receives monsoonal rainfall as infrequent events during hot summers, although there is signifi cant winter rain some years, especially in the southern Pilbara. Average annual rainfall is mostly 250–350 mm across the Pilbara and average temperatures in the hottest summer month (January) range from 36°C near the coast to 41°C inland (http://www.bom.gov.au/). Winters are warm and usually dry and annual pan evaporation is approximately 3500 mm (Luke et al. 2003). The three species described here were collected FIGURE 2 Localities of: from iron ore formations in two parts of the Hamersley Dodecastyla rima sp. nov., Range in the central Pilbara (Packsaddle Range and Dodecastyla crypta sp.