A Little Bit on Lesser Dung Flies

Copromyza stercoraria, photographed by Blaauw7.

The fly in the picture above is a typical member of the Sphaeroceridae, a family of over 1300 species of small flies that include some of the most ubiquitous of all insects. Despite their abundance, however, they rarely attract much attention from humans due to their small size, usually only about a couple of millimetres in length. Sphaerocerids are distinguished from other flies by the structure of the tarsus (the 'foot') on the hind leg. In most other flies, all the legs have the tarsi divided into elongate segments, but in sphaerocerids the first segment of the last tarsus is noticeably short and broad.

Sphaerocerids are sometimes referred to as 'lesser dung flies', referring of course to their small size and the diet of their larvae. However, lesser dung flies are not only associated with dung, but also feed on almost any form of decaying organic matter. They may be found on carrion or decaying vegetation or fungi. Some species may feed on a wide range of foodstuffs, but others are much pickier. One species, seemingly as yet unidentified, has been found in the excretory glands of a land crab. The coast-dwelling genus Thoracochaeta feeds on seaweed (Marshall & Buck 2010).

Podiomitra sp., photographed by Inna Strazhnik.

Though diverse, the majority of sphaerocerids are fairly conservative in appearance, including the Copromyza at the top of this post. There are, of course, notable exceptions. The individual just above is a representative of the Homalomitrinae, a rarely-collected subfamily of six known species in three genera from tropical Central and South America. The homalomitrines have a number of unusual features: their heads lack ocelli, have reduced bristles, and are more or less elongate; their thoraxes are relatively small; and the tarsi of all legs are short and broad. Two of the three genera, Sphaeromitra and Podiomitra, have markedly reduced venation in the wings. They do not have the appearance of strong fliers (though specimens have been collected in Malaise traps, indicating that they fly at least on occasion), but their extreme rarity (so far as is known) means that their lifestyles are almost unknown. Two species of Homalomitra, H. ecitonis and H. albuquerquei have been collected in association with army ants (Roháček & Marshall 1998), and it has been suggested that homalomitrines might develop in army ant middens, travelling phoretically by clinging to the ants with their modified tarsi (Marshall & Roháček 2003). However, it should be noted that this is largely speculative: the holotype of H. ecitonis, when collected, was reported to be walking amongst the supposed host ants, but otherwise little has been recorded of the nature of the association. It should also be noted that Roháček & Marshall (1998) suggested that H. ecitonis and H. albuquerquei form a clade to the exclusion of the other homalomitrine species, which further weakens confidence in extending the habits of these species to others.

There are also a number of species of sphaerocerid in which the wings are reduced or absent. The development of the wings may vary within a single species, as rather dramatically demonstrated by the specimen of Pullimosina meijerei shown above in a figure from Roháček (2012). This male exhibited unequal wing development, with the left wing that of a brachypterous individual but the right wing that of a macropter.

Sphaerocerids have been suspected as potential disease vectors due to their association with waste and decay, but actual evidence of negative impact on humans is rare. There appears to be at least one recorded case of sphaerocerid-caused intestinal myiasis (Marshall & Richards 1987), and sphaerocerids may become numerous enough to be a nuisance in places with a concentration of potential food, such as abattoirs or mushroom farms. Whatever their negative impacts may be, they are almost certainly outweighed by the positive: the ubiquitous sphaerocerids are probably major players in the process of breaking down waste materials and returning nutrients to the environment. They're the little flies that save you from being knee-deep in shit.

REFERENCES

Marshall, S. A., & M. Buck. 2010. Sphaeroceridae (small dung flies). In: Brown, B. V., A. Borkent, J. M. Cumming, D. M. Wood, N. E. Woodley & M. A. Zumbado (eds) Manual of Central American Diptera, vol. 2, pp. 1165-1187. NRC Research Press: Ottawa.

Marshall, S. A., & O. W. Richards. 1987. Sphaeroceridae. In: McAlpine, J. F. (ed.) Manual of Nearctic Diptera, vol. 2, pp. 993-1006. Biosystematics Research Centre: Ottawa.

Marshall, S. A., & J. Roháček. 2003. Podiomitra, a new genus of Homalomitrinae (Diptera: Sphaeroceridae) from Costa Rica. Proceedings of the Entomological Society of Washington 105 (3): 708-714.

Roháček, J. 2012. Wing polymorphism in European species of Sphaeroceridae (Diptera). Acta Entomologica Musei Nationalis Pragae 52 (2): 535-558.

Roháček, J., & S. A. Marshall. 1998. Revision of Homalomitrinae subfam. n. (Diptera: Sphaeroceridae), with the description of a new genus and three new species. European Journal of Entomology 95: 455-491.

Meet Australia's Newest Rake-legged Mite

Dorsal view of Neocaeculus imperfectus, as shown in Taylor et al. (2013).

Taylor, C. K., N. R. Gunawardene & A. Kinnear. 2013. A new species of Neocaeculus (Acari: Prostigmata: Caeculidae) from Barrow Island, Western Australia, with a checklist of world Caeculidae. Acarologia 53 (4): 439-452.

And, just in time for Christmas, here comes another publication for our lab! The paper is freely available for download, and represents my first foray into the world of mite taxonomy! So let me introduce to you the Barrow Island rake-legged mite, Neocaeculus imperfectus.

One of the most productive methods that we use for our collections on Barrow Island is suction sampling. This is exactly what it sounds like: we run a blower-vac over the vegetation, slurping up any bugs that might be sitting there. This usually provides us with a ton of material relatively quickly. The method's main caveat is that it provides mostly smaller stuff (larger insects are more likely to fly away before the blower-vac reaches them, or be strong enough to hang onto the vegetation as the vacuum passes over them). You also tend to confuse on-lookers who cannot work out why you are vacuuming the scrub.

Vital equipment for any entomologist.

So the average suction sample from Barrow Island will contain a lot of micro-wasps, a lot of leafhoppers... and one heck of a lot of one particular species of mite. The entire island seems to be crawling with these guys (or girls, rather: we've not yet identified a male, and it seems likely that this species is parthenogenetic). Some samples look to contain specimens numbering in the hundreds.

Like this.

It might seem surprising for the single most abundant species in a region to also be a completely new species to science, but this is indeed what we found. This particular mite belongs to a family called the Caeculidae, the rake-legged mites. The name refers to the presence of long spines on the front legs of these mites, which they use in capturing prey. Otto (1993) observed live individuals of another species, Microcaeculus pica, and found that they would stand in once place, immobile, with their front legs raised above the ground. When a small animal such as a springtail walked underneath the raised legs, the mite would drop them down, and the spines would act like a cage, trapping the victim. This habit of remaining perfectly still goes some way to explaining another interesting detail about the Barrow Island caeculids: despite their apparent abundance, we've never seen them alive in the field (I have occasionally seen one walking about in the lab when sorting samples). Presumably their motionlessness makes them almost invisible.

Unidentified caeculid, photographed in South Africa by Jon Richfield.

Caeculids are common in many parts of the world, particularly in arid regions, but they've never gotten much love; relatively little has been published on them. A large part of this is that they're difficult to work with under a microscope, being dark and heavily sclerotised. Their aforementioned crypsis also means that they are often overlooked and may be difficult to collect. The last person to work extensively on caeculids, the now-retired French researcher Yves Coineau, reported that he collected specimens by filling a tray with leaf litter and then blowing tobacco smoke over it to make the mites move (Coineau 1974). This method would probably not be recommended today. Because of the difficulty in finding information on caeculids, we also included in our paper a key to the genera and a complete checklist of the species of the world.

Finally, in case you were wondering, 'imperfectus' is Latin for 'undeveloped'. Neocaeculus imperfectus is something of an apparently neotenous form compared to other caeculids, with adults retaining a number of juvenile features such as a low number of dorsal setae.

It's just the cutest little baby face.

REFERENCES

Coineau, Y. 1974. Éléments pour une monographie morphologique, écologique et biologique des Caeculidae (Acariens). Mémoires du Muséum National d’Histoire Naturelle, Série A, Zoologie 81: 1-299, pls 1-24.

Otto, J. C. 1993. A new species of Microcaeculus from Australia (Acarina: Caeculidae), with notes on its biology and behavior. International Journal of Acarology 19 (1): 3-13.

Barrow's Scaly Bark-louse

Male of Lithoseopsis humphreysi, from Taylor (2013). As this specimen has been preserved in ethanol, most of the wings' scales have been washed off.

In yesterday's post, I told you about our project's new book on the terrestrial invertebrates of Barrow Island. In this post, I want to tell you about my own main contribution: a description of Barrow Island's resident species of Amphientomidae.

Amphientomidae is a family of the bark-lice, the Psocodea (or Psocoptera, perhaps). They differ from most other bark-lice in having the wings densely covered in scales, like the wings of a moth; someone on BugGuide once referred to an amphientomid as a "moth-hopper-louse-bug thingy". These scales are often arranged into striking patterns of contrasting colours (take a look at the individual below). When the late Courtenay Smithers initially identified our collections of bark-lice from Barrow Island (which we briefly reviewed last year, though most are still not identified to formal species), he highlighted the presence of an amphientomid in the collection as particularly interesting. Amphientomids are incredibly little known in Australia. Only three Australian species had previously been described, and all three were only known from a single specimen. The description in my paper is drawn from six specimens, so it represents a tripling of Australia's published tally!

A North American species of Lithoseopsis, L. hellmani, photographed by Diane Young.

With this in mind, a description of the Barrow Island amphientomid seemed in order. This, of course, required comparing it to the already-described Australian species, which had thankfully been given detailed descriptions (Smithers 1989; New 1994). Two of these were from Western Australia: one from the Kimberley region in the far north, the other from the Cape Range which is on the mainland close to Barrow Island. Both of these had been placed in the genus Seopsis, which is otherwise known from Africa and Asia. However, when I compared the Barrow Island specimens to descriptions of Seopsis and other Asian genera, things didn't quite add up. For instance, take a look at the face of the Barrow Island species:

In particular, note the position of the ocelli (the three simple eyespots) at the front of the face. In all the Australian species, these are widely spaced, and the two lateral ocelli are right alongside the compound eyes. In contrast, here is the face of a Japanese amphientomid:

The individual in this photo, from here, isn't identified but may belong to Paramphientomum yumyum (yes, really, that's its name). Note how in this species, all three ocelli form a close triangle in the centre of the face; Seopsis also has this arrangement of ocelli. Other features such as genital morphology were also inconsistent between the Western Australian species and Seopsis.

Instead, the Western Australian species are better placed in a genus called Lithoseopsis*. The Barrow Island specimens I assigned to the same species that had earlier been described from the Cape Range, Lithoseopsis humphreysi. There are some minor differences between the Barrow specimens and the Cape Range holotype, but with only one specimen available from the latter locality I couldn't really assess whether these were indicative of more than one species. The recognition of this species as Lithoseopsis is interesting, as this genus is otherwise known only from southern North America. How such an oddly disjunct distribution may have come about I have no idea; my first guess would be that it's somehow relictual. However, it's also worth pointing out that there are three other genera very similar to Lithoseopsis that share its broadly-spaced ocelli: the African genus Hemiseopsis and the circum-Mediterranean genera Marcenendius and Nephax. The relationship between these genera really deserves a proper study.

*And here's a bit of a cautionary tale for you all. When I initially submitted the manuscript of this paper for review, one of the reviewers pointed out that the Western Australian species shouldn't be placed in Lithoseopsis due to the absence of one of that genus' primary features, a sclerotised plate on the back of the abdomen. Therefore, the manuscript was revised and accepted to establish the WA species as a new genus. At this point, I should note, the only amphientomids that had been available from Barrow Island were males. However, shortly before the book was due to be published, I finally received a female specimen. This specimen possessed the sclerotised plate that had been absent in the males! The paper was quickly revised at the last minute to return the WA species to Lithoseopsis. The ability to examine a female from Barrow also lead me to change my mind about whether the Barrow species was distinct from the Cape Range species, represented only by a female holotype. Unfortunately, once the book had been published and I could see the final product, I found that I had missed correcting the genus and species name in the figure captions! Much wailing and gnashing of teeth immediately commenced, I can bloody well tell you. After the whole pureora/pureroa thing, 2013 has not made me look good as a proof-reader.

The Barrow Island specimens also tell us something interesting about intra-specific variation in amphientomids. A common feature of bark-lice is variation within species of wing development: individuals of a single species may have the wings fully developed, reduced or absent. In amphientomids, however, such variation has been rarely recorded. A couple of species are known in which males and females differed in wing development, but so far as was known all males and all females had wings the same size. In the Barrow Island specimens, however, some males had both pairs of wings large and fully developed, but others had the forewings slightly shortened and the hind wings reduced to minute flaps. As the reduced-wing specimens were otherwise little different from the fully-winged specimens, they seem unlikely to represent different species. Instead, Lithoseopsis humphreysi is the first recorded example for amphientomids of wing polymorphism within a single sex.

REFERENCES

New, T. R. 1994. A second species of Amphientomidae (Insecta: Psocoptera) from Western Australia. Proceedings of the Linnean Society of New South Wales 114 (4): 233–236.

Smithers, C. N. 1989. Two new species of Amphientomidae (Insecta: Psocoptera), the first record of the family for Australia. Proceedings of the Linnean Society of New South Wales 111 (1): 31–35.

Taylor, C. K. 2013. The genus Lithoseopsis (Psocodea: Amphientomidae) in the Western Australian fauna, with description of the male of Lithoseopsis humphreysi from Barrow Island. Records of the Western Australian Museum Supplement 83: 245-252.

The Terrestrial Fauna of Barrow Island

Nihara R. Gunawardene, Jonathan D. Majer, Christopher K. Taylor & Mark S. Harvey (eds) 2013. The Terrestrial Invertebrate Fauna of Barrow Island, Western Australia. Records of the Western Australian Museum, Supplement 83. 406 pp.

For several years now, my colleagues and I have been monitoring terrestrial invertebrates on Barrow Island here in Western Australia. Some of you will have already heard of Barrow Island; for anyone that hasn't, Barrow is the second-largest island off the coast of WA (it's about 25 km long and 12 km wide). It has two main claims to fame: (a) it has been a recognised nature reserve for over 100 years, with thriving populations of a number of animals that are rare or extinct elsewhere, and (b) for the last 50 years, it has also been a working oil field, most recently managed by the oil company Chevron. It also lies close to large offshore natural gas deposits, and in 2003 Chevron and its associates were given permission to build a processing plant on Barrow Island for extraction of the gas. This permit, however, carried strong caveats: development of the plant is not to compromise the value of Barrow as a nature reserve. That's where we come in: on a regular basis, we travel to the island to look for any undesirables that may have managed to slip through the stringent quarantine requirements that have been placed on transport to Barrow (nothing so far, touch wood). Before plant development was begun, a large-scale survey was also conducted to identify the pre-existing invertebrate fauna of Barrow Island: before you can say whether something isn't there, you need to be able to say what is.

Over the course of these surveys, a sizeable collection of material has been accumulated from an area that had previously been only sporadically sampled. Over two dozen taxonomic experts were consulted in the process of identifying this material, a lot of which represented species potentially new to science. And so, some time in 2012, we asked the people who had been involved with the project if they would like to contribute to a collection of papers on Barrow Island invertebrates. The response was mostly positive, and The Terrestrial Invertebrate Fauna of Barrow Island, Western Australia was released to the world a couple of weeks ago.

We're very pleased with how it turned out. Some of the contributors provided overviews of their taxon of interest; others provided descriptions of new species. Authors came from both the academic and private sectors, and we're grateful to everyone who put time and effort into answering our calls. In the end, we had 22 chapters on hand, including material on animals from arachnids to isopods to ants, and 25 new species: one snail, two spiders, a silverfish and 21 flies. Not all of these new species were from Barrow Island alone: the chapter on Dolichopodidae (long-legged flies) by Dan Bickel represents a review of the fauna of the entire Pilbara region.

The book is available for purchase from the Western Australian Museum, but I've noticed that their site doesn't provide an article listing. Therefore, I'm including one below, with the abstracts for each article. Contact details for the corresponding authors have been included as hyperlinks, if you want to ask them about their articles. And again, thank you to everyone involved.

The camaenid snail Rhagada barrowensis. The identity of Barrow Island's common Rhagada species has been subject to a bit of confusion over the years; Johnson et al. describe it as a new species in this book.

Dorian Moro and Russell Lagdon, pp. 1-8.
History and environment of Barrow Island

Barrow Island represents a unique island ecosystem off north-western Australia. It has ecological affinities to the Cape Range region of the Australian mainland, and it also supports an oil and gas resource industry. The island hosts a long-unburnt vegetation complex, and a diverse community of vertebrate and invertebrate fauna occupy the disturbed and undisturbed habitats of the island. In the absence of non-indigenous predators or herbivores, without extensive land clearing, and with an instituted level of island quarantine, these environmental values have persisted to make Barrow Island an important environmental asset for Australia, and an example where island ecology functions in the presence of resource extraction. To date, almost 2,800 species of terrestrial and subterranean species have been consistently recorded from Barrow Island. These include 378 native plant species, 13 mammal species (including two species of bats), at least 119 species of terrestrial and migratory birds, 43 species of terrestrial reptiles, one species of frog, three subterranean vertebrates, at least 34 species of subterranean invertebrates, and the most speciose of all, over 2,200 terrestrial invertebrates.

Russell Lagdon and Dorian Moro, pp. 9-11.
The Gorgon gas development and its environmental commitments

Chevron has made an important contribution to our knowledge and understanding of the Barrow Island flora and fauna, and to the Australian economy. This knowledge has been primarily founded from the investigations and commitments of joint venture partners associated with the environmental impact assessment for the Gorgon Gas Development. The Gorgon Gas Development is one of the world’s largest natural gas projects and the largest single natural gas project in Australia’s history. Development has been balanced between energy needs and environmental management. Through plans, procedures, programs and research, Chevron Australia and its joint venture participants have established a benchmark for environmental management of this important island reserve. Furthermore, the Gorgon Joint Ventures have contributed to one of the largest biodiversity offset and Net Conservation Benefit programs in Western Australia.

Jonathan D. Majer, Shae K. Callan, Karl Edwards, Nihara R. Gunawardene and Christopher K. Taylor, pp. 13-112.
Baseline survey of the terrestrial invertebrate fauna of Barrow Island

Barrow Island is Western Australia’s second largest offshore island and its flora and fauna have been able to evolve without major human disturbances. Chevron Australia Pty Ltd and its Joint Venture Participants made an application to construct a plant to liquefy natural gas on the island in 2001. One of the conditions under which approval was granted was the implementation of a rigorous biosecurity effort to ensure that no non-indigenous species (NIS) are introduced or allowed to establish on the island. To fulfil this condition it was first necessary to characterise what was already present on the island. A series of surveys have been performed using a purpose-designed sampling protocol in order to provide baseline data on the existing terrestrial invertebrates on Barrow Island. A total of 1,873 morphospecies were sampled but subsequent surveys and taxonomic developments have increased the count to 2,397. This compares with an estimated species richness of 2,481 terrestrial invertebrate species on the island. Composition of the fauna varied considerably between the wet and dry seasons and between years, even when samples were taken during the same month. Composition also varied with distance from the coast, which may be associated with soil type and vegetation association. Twenty five non-indigenous species and seven putative non-indigenous species have been found, all of which are believed to have been present prior to commencement of the Gorgon Gas Development project.

Peter Whittle, Frith Jarrad and Kerrie Mengersen, pp. 113-130.
Design of the quarantine surveillance for non-indigenous species of invertebrates on Barrow Island

The Ministerial conditions for regulatory approval for the Gorgon gas project on Barrow Island included a quarantine surveillance program having detection power of 0.8 for non-indigenous species of terrestrial invertebrates, vertebrates and plants. No method was available for design of such a program, so we developed a new method and designed surveillance systems that were implemented successfully in 2010−11 for the first of four years over the construction period. Here we describe the method and outline the invertebrate surveillance system, after the experience of the first year. We discuss a set of issues that characterised the design problem, which we consider typical of many surveillance applications. We suggest that the method is broadly applicable for objective design of surveillance, for biosecurity and other settings.

Ken Walker, pp. 131-134.
Providing web based diagnostics for the Barrow Island baseline survey

During the years of 2005 to 2007, an extensive baseline study of the Barrow Island invertebrate fauna was conducted. This survey included more than 50 sample sites across the island and multiple collecting techniques were used at each site. Over 14,000 specimens were collected during this survey. Taxonomic specialist who examined this material nominated over 2,000 morphospecies of which about 300 could be placed to species rank. Having done all of this collecting and identification, the question then was how best to access and use this valuable resource. All of the specimens were stored in two institutions in Perth – several thousand kilometres south of Barrow Island. Manual access to these specimens was slow which hindered the decision making processes needed when a suspected non-indigenous species was found on the island. The decision was made to digitise the diagnostic characters for representative of each morphospecies. These images were to be made available through a website called PaDIL (Pests and Diseases Image Library). Each species was to have its own webpage containing at least 4 diagnostic images of each species and all of the species collection points to be displayed on an interactive Google Map. Species, as well as higher ranks, could be queried alone or against sample localities or against Indigenous or Non-Indigenous status. Individual species pages could be opened and comparative images tables could be pre-defined and presented or users could build their own comparative image tables in real time. The development of the Barrow Island PaDIL website made the results of the entire Baseline Study accessible to anyone with a web browser from anywhere with an internet connection. The Barrow Island PaDIL website is a major part of the Quarantine efforts of Chevron on Barrow Island.

Christopher K. Taylor, pp. 135-144.
Annotated bibliography for Barrow Island terrestrial invertebrates

A bibliography is provided of publications treating terrestrial invertebrates on Barrow Island. A brief overview is also given of natural history and invertebrate collections on Barrow Island.

Garth Humphreys, Jason Alexander, Mark S. Harvey and William F. Humphreys, pp. 145-158.
The subterranean fauna of Barrow Island, north-western Australia: 10 years on

Barrow Island, situated off the north-west Australian coast, is well recognised for its subterranean fauna values. Sampling for both stygobitic and troglobitic fauna has taken place on the island since 1991, and Humphreys (2001) summarised the then current state of knowledge of the island’s subterranean fauna. Sampling for impact assessment purposes on the island over the past decade has substantially increased the recorded species richness of Barrow Island. The number of documented stygal taxa has more than doubled since 2001, from 25 to 63 species now known. Troglobitic diversity has also substantially increased, with six species known in 2001 and 19 troglobitic taxa known today. The total recorded subterranean species richness for Barrow Island at this time stands at 82 species. It is likely that considerably more species remain to be recorded, as even the additional surveys of the past decade leave many areas of the island unsampled.
The distributions and minimum area of occupancy for many species known from Barrow Island in 2001 have also been significantly expanded by the sampling efforts of the last decade. This includes specially protected species listed under State and Commonwealth Government legislation. The available data suggest the fauna of the island may number in the hundreds of species, many of which are endemic, confirming its status as internationally significant for subterranean biota.

Michael S. Johnson, Sean Stankowski, Corey S. Whisson, Roy J. Teale and Zoë R. Hamilton, pp. 159-171.
Camaenid land snails on Barrow Island: distributions, molecular phylogenetics and taxonomic revision

Three species of camaenid land snails occur on Barrow Island: Quistrachia barrowensis and two previously unassigned species of Rhagada. Based on morphological re-evaluation and analysis of sequences of the mitochondrial gene COI, we have revised the taxonomy of these species, providing a clearer understanding of their geographic distributions and origins. The supposed Barrow Island endemic Q. barrowensis is synonymous with Q. montebelloensis from the Montebello and Lowendal Islands. The small species of Rhagada, confined to the northern tip of Barrow Island, is conspecific with R. plicata, whose distribution also includes the Montebellos and the Lowendals. The large species of Rhagada is described here as R. barrowensis sp. nov., known only from Barrow Island and adjacent Pascoe Island. The three camaenids represent deeply divergent lineages with different geographic origins, indicating that the local diversity on Barrow Island has come about through a complex history. With maximum geographic spans of only 22 to 70 km, the short-range endemism of these species highlights the conservation significance of Barrow Island.

Volker W. Framenau and Anna E. Leung, pp. 173-184.
Costacosa, a new genus of wolf spider (Araneae, Lycosidae) from coastal north-west Western Australia

A new genus of wolf spider (family Lycosidae Sundevall, 1833), Costacosa gen. nov. is described from north-west Western Australia to include C. torbjorni sp. nov. (type species) and C. dondalei sp. nov. The genus belongs to the subfamily Lycosinae Sundevall, 1833 and differs from all other Australian genera in this subfamily with similar somatic morphology, in particular Venator Hogg, 1900 and Knoelle Framenau, 2006, mainly in genitalic characters. The tegular apophysis of the male pedipalp has a pronounced ventral spur, a distinct ventral edge of species-specific shape and serrations along its apical edge. The female epigyne has an elongated triangular atrium and the medium septum is longer than the posterior transverse part. Costacosa are medium-sized wolf spiders of overall brown colouration and with broad light median and sublateral bands on the carapace and a black patch in the frontal two-thirds of the venter. Costacosa torbjorni is the most commonly recorded wolf spider on Barrow Island, from where currently seven species of Lycosidae are known.

Simon Judd and Giulia Perina, pp. 185-207.
An illustrated key to the morphospecies of terrestrial isopods (Crustacea: Oniscidea) of Barrow Island, Western Australia

This paper presents an illustrated key to eighteen morphospecies of terrestrial isopods from Barrow Island with a brief summary regarding their currently known distribution and potential endemicity to the island. Six described species are recorded, Ligia exotica (family Ligiidae), Alloniscus pallidulus (Alloniscidae), Laevophiloscia yalgooensis (Philosciidae), Porcellionides pruinosus (Porcellionidae), Barrowdillo pseudopyrgoniscus, Buddelundia hirsuta (both Armadillidae), but the identifications of most need to be confirmed following genus-level revisions and examination of type- or topotypical material. The key includes twelve undescribed species and at least two undescribed genera from the family Armadillidae, one of which is apparently restricted to Barrow Island. Although there is still considerable taxonomic work required to evaluate distributions, it appears that at least six of the eighteen species are potential short-range endemics (SRE).

Catherine A. Car, Megan Short, Cuong Huynh and Mark S. Harvey, pp. 209-219.
The millipedes of Barrow Island, Western Australia (Diplopoda)

Six species of millipedes are recorded from Barrow Island, including three species of pin-cushion millipedes of the order Polyxenida, Lophoturus madecassus (Marquet and Condé, 1950) (Lophoproctidae), Unixenus mjoebergi (Verhoeff, 1924) (Polyxenidae) and Phryssonotus novaehollandiae (Silvestri, 1923) (Synxenidae), a single species of the order Spirobolida, Speleostrophus nesiotes Hoffman, 1994 (Trigoniulidae), and two species of the order Polydesmida, Boreohesperus dubitalis Car and Harvey, 2013 (Paradoxosomatidae) and one species of the family Haplodesmidae (genus and species indet.). Lophoturus madecassus is circum-tropical in distribution, Unixenus mjoebergi and Phryssonotus novaehollandiae are found also on mainland Australia, but the other three species are endemic to the island. Speleostrophus nesiotes is a highly modified troglobiotic species, currently listed as threatened by the Western Australian government. It is unclear at present whether the haplodesmid specimen is a troglobite.

Penelope Greenslade, pp. 221-228.
Composition of Barrow Island collembolan fauna: analysis of genera

Collembola have been collected from Barrow Island for the first time; a maximum of seventy one species were detected, of which a high proportion are undescribed. Only four non-indigenous species (NIS) species have been collected, three in very small numbers but one was a large population introduced to the island in lengths of timber which were subsequently sent off the island. Despite few of the species being described, most have been collected before and endemism is low. One new genus record for Australia, Calx, was found. The presence of a species of Temeritas is unusual in that the males showed strong sexual dimorphism, and a species of Acanthocyrtus that lacked any pigment was collected in reasonable numbers. Collections from bore holes were rich in species. Five species were recorded only from bore holes and may be island endemics. The intertidal fauna was also rich in species with 14 found, all restricted to this habitat. Soil fauna density of Collembola was found to be high, with a mean average potential density of nearly 47,000/m². A proportion of the terrestrial Collembola fauna is active under all weather conditions but other species are only active after rain. In general, the terrestrial fauna shows a dominance of the families Isotomidae and Bourletiellidae, which is typical for the wet/dry tropics where trees are absent.

Graeme Smith, pp. 229-240.
A new species of Heterolepisma from Barrow Island (Zygentoma: Lepismatidae)

The silverfish fauna of Barrow Island is discussed and Heterolepisma parva sp.nov. is described from extensive material collected mostly in pitfall traps or Winkler sac leaf litter samples.

David T. Jones, pp. 241-244.
The termites of Barrow Island, Western Australia

Forty years ago D. H. Perry, the renowned termite expert, published a checklist of 18 species that he had collected on Barrow Island. That checklist is now updated with the results of a recent invertebrate survey of the island, and a literature search for additional records. The updated list now runs to 27 species, all of which appear to be indigenous to the island.

Christopher K. Taylor, pp. 245-252.
The genus Lithoseopsis (Psocodea: Amphientomidae) in the Western Australian fauna, with description of the male of Lithoseopsis humphreysi from Barrow Island

The Australian Amphientomidae species Seopsis incisa Smithers, 1989 and S. humphreysi New, 1994 are transferred to the genus Lithoseopsis Mockford, 1993 as L. incisa new combination and L. humphreysi new combination, as a result of the discovery of speciens of L. humphreysi from Barrow Island, Western Australia. The male of L. humphreysi is described for the first time, and both macropterous and brachypterous individuals are described. The genus Lithoseopsis was previously known from North America only, and the addition of the Western Australian species significantly increases its range. A key is provided to the genera of Amphientomidae.

David Gopurenko, Murray Fletcher, Holger Löcker and Andrew Mitchell, pp. 253-285.
Morphological and DNA barcode species identifications of leafhoppers, planthoppers and treehoppers (Hemiptera: Auchenorrhyncha) at Barrow Island

The hemipteran suborder Auchenorrhyncha comprises a rich assemblage of plant feeding species, many of which are widespread in distribution and act as vectors of viral and fungal diseases affecting plants. Species level identifications in this group generally are possible only by examination of male specimens; prior DNA barcode analyses of a limited range of Auchenorrhyncha indicate that this approach may provide an expedient means to identify species within this diverse group. In this study we explored the utility of DNA barcoding for identification of a wider range of Auchenorrhyncha species than has been examined previously. Diverse fulgoroid (planthopper) and membracoid (leafhopper and allies) Auchenorrhyncha were sampled from Barrow Island, Western Australia, and identified to the least inclusive taxonomic units using morphology. DNA barcodes from 546 adult specimens were obtained and analysed using a General mixed Yule – Coalescent (GMYC) modelling approach to genetically delimit putative species, as a comparison to the morphospecies identifications. Additional DNA barcodes (N = 106) were obtained from nymphs and these were compared to adult DNA barcodes to identify species present among immature specimens.
Among adult specimens, 73 species were congruently delimited by morphology and genetic analyses when modelled using a single threshold GMYC. Congruence between morphological and molecular species assignments was greatly reduced when the Yule – Coalescent transition was allowed to vary across genetic lineages. In a separate DNA barcode analysis of all specimens using neighbour joining distance metrics, nymphs and physically degraded specimens were in most cases genetically linked to adult conspecifics. Ten genetic clades detected among the nymphs were not observed among adults and did not match pre-existing sequence accessions in GenBank or DNA barcode records in BOLD.
Of the 73 adult Auchenorrhyncha species congruently identified by DNA barcoding and morphology, most were Cicadellidae (N = 53 morphospecies), the remaining 20 morphospecies were sparsely representative of ten other families. Formal identifications to species level were available for only 36% of these 73 morphospecies, owing mainly to an absence of diagnostic male specimens within many of the delimited species. Indeterminate species detected among adults and nymphs are designated with interim species codes.
The work presented here demonstrates that DNA barcoding is likely to be a powerful investigative tool for identifying and understanding species limits in the Auchenorrhyncha, particularly if it is used within an integrative taxonomic framework.

Laurence A. Mound, pp. 287-290.
Thysanoptera (Insecta) of Barrow Island, Western Australia

Almost 50 species of the insect order Thysanoptera are here listed from Barrow Island, Western Australia, of which several are known only from this island. This cannot be interpreted as indicating that any species is endemic to the island, because almost nothing is known of the Thysanoptera fauna of the nearby mainland.

Daniel J. Bickel, pp. 291-348.
The family Dolichopodidae (Diptera) of the Pilbara region, Western Australia in its Australasian biogeographic context, with the description of 19 new species

The Dolichopodidae (Diptera) of the Pilbara Region (here also including Barrow Island and Cape Range), Western Australia are described, keyed and illustrated. The fauna comprises 41 species, including three with generic names only, being represented by females or badly damaged males. The following 19 species are newly described: Pseudoparentia canalicula sp. nov., Pseudoparentia niharae sp. nov., Paraclius manglar sp. nov., Medetera junensis sp. nov., Corindia gascoynensis sp. nov., Thinophilus eboricoxa sp. nov., Thinophilus yarraloola sp. nov., Chaetogonopteron capricorne sp. nov., Chaetogonopteron vexillum sp. nov., Sympycnus colliepa sp. nov., Sympycnus lacrimulus sp. nov., Sympycnus pistillus sp. nov., Sympycnus weano sp. nov., Sympycnus ephydroides sp. nov., Sympycnus hamulitarsus sp. nov., Diaphorus karijini sp. nov., Diaphorus garnetensis sp. nov., Chrysotus austrotropicus sp. nov. and Chrysotus pilbarensis sp. nov. Paraclius obtusus Hardy, 1939 is regarded as a new senior synonym of Paraclius albodivisus Parent, 1941, syn. nov. The Pilbara fauna is treated in the context of the wider Australian fauna, and many extralimital records are included. Many Pilbara species are found across tropical northern Australia, and sometimes into adjacent Melanesia. However, some species have a trans-continental distribution south of the monsoonal belt and also occur in central Northern Territory and subtropical interior Queensland suggesting a biogeographic track that now comprises favorable relictual habitats in a largely arid region. The Millstream site along the Fortescue River is particularly rich in species, and it is the only known locality of the isolated monotypic genus Pilbara Bickel.

David K. Yeates and Stefanie K. Oberprieler, pp. 349-354.
Two new species of the Australian bee fly genus Comptosia (Diptera: Bombyliidae) from Barrow Island, Western Australia

Two new species of the bee fly genus Comptosia Macquart from Western Australia, C. barrowensis and C. karijinii, are described.

Nicholas B. Stevens, Syngeon M. Rodman, Tamara C. O’Keeffe and David A. Jasper, pp. 355-374.
The use of the biodiverse parasitoid Hymenoptera (Insecta) to assess arthropod diversity associated with topsoil stockpiled for future rehabilitation purposes on Barrow Island, Western Australia

This paper examines the species richness and abundance of the Hymenoptera parasitoid assemblage and assesses their potential to provide an indication of the arthropod diversity present in topsoil stockpiles as part of the Topsoil Management Program for Chevron Australia Pty Ltd Barrow Island Gorgon Project. Fifty six emergence trap samples were collected over a two year period (2011 and 2012) from six topsoil stockpiles and neighbouring undisturbed reference sites. An additional reference site that was close to the original source of the topsoil on Barrow Island was also sampled. A total of 14,538 arthropod specimens, representing 22 orders, were collected. A rich and diverse hymenopteran parasitoid assemblage was collected with 579 individuals, representing 155 species from 22 families. The abundance and species richness of parasitoid wasps had a strong positive linear relationship with the abundance of potential host arthropod orders which were found to be higher in stockpile sites compared to their respective neighbouring reference site. The species richness and abundance of new parasitoid wasp species yielded from the relatively small sample area indicates that there are many species on Barrow Island that still remain to be discovered. This study has provided an initial assessment of whether the hymenoptera parasitoid assemblage can give an indication of arthropod diversity. However, further work would still be required to more robustly establish the use of the hymenoptera parasitoid assemblage as indicators of arthropod diversity.

B. E. Heterick, pp. 375-404.
A taxonomic overview and key to the ants of Barrow Island, Western Australia

This work characterises the ant (Hymenoptera: Formicidae) fauna of Barrow Island, Western Australia, and provides a key to the workers and several unique reproductives of the 117 species recorded from the island thus far. In all, 11 of the 13 subfamilies of Western Australian ants have been recorded from Barrow Island, but Myrmeciinae and Heteroponerinae are absent. At a generic level, the fauna of the island is less rich, holding 36 of the 71 genera currently known from Western Australia. The ant fauna is characteristic of the Eremaean Botanical Province of the Pilbara, rather than that of the Carnarvon Basin from which Barrow Island is geologically derived. Ninety-three ant species (79.5% of the total on Barrow Island) are shared with the ant fauna of the Pilbara region on the adjoining mainland, but only 52 species (44.4% of the total) are shared with the ant fauna of the Carnarvon Basin. The island is very rich in unspecialised and thermophilic ant species. Five such genera, i.e., Iridomyrmex (14 spp.), Monomorium (13 spp.), Polyrhachis (12 spp.), Melophorus (10 spp.), and Camponotus (nine spp.) make up almost 50% (i.e., 49.6%) of the island’s ant fauna. Very few ants appear to be endemic to Barrow Island. The relative proportions of the two major subfamilies (Formicinae and Myrmicinae, together comprising 61.5% of the total ant richness) are similar to the proportions found in the South-west Botanical Division for these two subfamilies (i.e., 65.9%), with Barrow Island having a slightly lower ratio of formicines to myrmicines than is found in the south-west of the state. An estimate of the total number of ant species likely to occur on Barrow Island, using the Estimate-S program (Colwell 2009), suggests that a maximum of fourteen additional species may be as yet unrecorded.

Jonathan D. Majer, Nihara R. Gunawardene, Christopher K. Taylor and Mark S. Harvey, pp. 405-406.
A last word

The work reported on in this volume is the culmination of nine years of data gathering stemming from the original baseline surveys on Barrow Island. Not surprisingly, this has resulted in one of the most comprehensive terrestrial invertebrate surveys ever performed on an offshore island on this continent. There are other substantial surveys, but these have generally focussed on specific taxonomic groups, rather than the whole spread reported here.

Proasellus: Life Under Water

Proasellus slavus, photographed by Hans Jürgen Hahn K. Grabow (see comments below re credits).

The animal in the picture above is not quite the animal that I was planning on telling you about today, but I couldn't find an image of my particular target species. As long-time readers of this page will know, once a week I pick some random taxon to look at, and for this week I picked out the freshwater isopod Proasellus vignai. Most of you will know isopods as the woodlice that you may find in your garden, but the woodlice are really only one small part of the broad range of mostly aquatic isopod diversity. Proasellus belongs to a group of isopods known as the Asellota; as you can see in the picture above, asellotes differ from woodlice in (amongst other things) having the dorsal shields of each segment less tightly pressed together.

Proasellus is a genus of freshwater asellotes found around the Mediterranean: Europe, western Asia, northern Africa. Proasellus vignai is one of a number of species of Proasellus that are found in subterranean habitats, like P. slavus shown above. Both P. slavus and P. vignai, like most other subterranean animals, have lost the pigment and eyes of their surface-dwelling relatives. However, not all subterranean habitats are equal, and not all subterranean animals live in 'caves' as you might usually imagine them. Some Proasellus species are indeed found living in caves, but P. vignai and P. slavus are inhabitants of the hyporheic zone, the ground around rivers and streams where the water from the river soaks into the surrounding groundwater. Cave-dwelling Proasellus species tend to be broader and have more elongate limbs, so that they can maximise their chances of finding food in the nutritionally sparse cave waters. Hyporheic species, on the other hand, are narrower and more elongate, making them better suited for squeezing through the gaps between sediment particles.

Proasellus vignai seems to be a little known species (hence the lack of an available illustration). It is only known from the hyporheic zone of the Melfa river, in the Appenine mountains of the Lazio region of Italy (Bodon & Argano 1982). The Melfa is not a long river, only about 40 km long, so P. vignai may be a very localised species. It is a close relative of P. slavus, which lives in the water catchment of the Danube River. Other related species include P. ligusticus in the Ligurian Alps, P. sketi in Greece and P. boui in Languedoc in southern France. The scattered nature of the species of the P. slavus group, all of them hyporheic, suggests a certain degree of relictualism. Like other habitats that represent the edge of things, the hyporheic environment can be an uncertain one, vulnerable to outside influences. Should something change the nature of the Melfa river, Proasellus vignai might be taken with it.

REFERENCE

Bodon, M., & R. Argano. 1982. Un asellide delle acque sotterranee della Liguria orientale: Proasellus ligusticus n.sp. (Crustacea, Isopoda, Asellota). Fragm. Entomol. 16 (2): 117-123.

Oribotritia: Some Mites Just Want to be Left Alone

I'm aware that a lot of people would not automatically think of mites when categorising cuteness, but I dare you to look at the animal in the photo above (taken by Tom Murray) and tell me it's not adorable. This is a box mite of the genus Oribotritia, a cosmopolitan genus found on all the continents except Australia. More than 80 species of Oribotritia have been described so far, and there's probably more to come. Box mites are armoured mites with a body form known as 'ptychoid'; as described in an earlier post, this means that the legs can be drawn back close to the body, and the prodorsum (the articulated shield at the front of the body covering the mouthparts folded over to cover the soft parts. The figure below from Schmelzle et al. (2009) shows how it works. The mite on the left is Oribotritia banksi, the one on the right is a different ptychoid, Rhysotritia ardua:

This figure also shows some of the distinguishing features of Oribotritia. There are a number of families of ptychoid mites; interestingly, indications are that not all ptychoids are directly related to each other. Instead, the ptychoid morphology has evolved a number of times. Oribotritia belongs to the 'true' box mites, in which the notogaster (the main 'body' of the mite) is a single undivided dorsal plate, while the genital and anal plates are long and together occupy the entire length of the underside. The three main families of true box mites are the Phthiracaridae, Oribotritiidae and Euphthiracaridae. Phthiracarids have the ventral plates broad and the venter overall more or less U-shaped; the other two families have the venter narrow and triangular. In oribotritiids like Oribotritia, the genital and anal plates have another elongate pair of plates running outside them, but in euphthiracarids (like Rhysotritia ardua in the figure above), all the ventral plates have become fused into a single plate pair.

When fully withdrawn into its sclerotised shell, the ptychoid mite is pretty effectively sealed away from would-be predators. As well as this mechanical defense, glandular openings on the side of the notogaster secrete defensive oils to repel predators chemically. The overall aim is that the mite should simply be left unmolested to pursue its own interests: feeding on decaying vegetation.

REFERENCES

Balogh, J., & P. Balogh. 1992. The Oribatid Mites Genera of the World. Hungarian Natural History Museum: Budapest.

Schmelzle, S., L. Helfen, R. A. Norton & M. Heethoff. 2009. The ptychoid defensive mechanism in Euphthiracaroidea (Acari: Oribatida): a comparison of muscular elements with functional considerations. Arthropod Structure and Development 38: 461-472.

Hyperamminids: A Rough Retort

Hyperammina elongata, photographed by Onno Groß.

Agglutinated foram time again! In previous posts, I've described how these aquatic amoeboids construct coverings for themselves by cementing together particles from the surrounding environment. In the family of forams I'm presenting you with today, the Hyperamminidae, their choice of particle is generally sand grains, glued together with a relatively small amount of cement. As a result, hyperamminids often have a quite rough appearance to their walls. They live free, not cemented to their substrate. The test is not divided into chambers; instead, it starts as a globular chamber (the proloculus) that opens into an elongate tube. The overall appearance, therefore, is not dissimilar to one of those glass cylinders with a basal bulb (like an old thermometer). In species of Hyperammina, the tube is simple and tapers as it gets further from the proloculus. In contrast, the genus Saccorhiza has the tube more constant in diameter, and also has the tube branching dichotomously (Loeblich & Tappan 1964). Hyperamminids are abundant in the deep sea, and though certainly not among the largest forams, they can easily be a millimetre or more in size.

Agglomeration of Saccorhiza ramosa tubes, from here.

The classification of agglutinated forams presented by Kaminski (2004) lists six genera in the Hyperamminidae, with separate subfamilies for Hyperammina and Saccorhiza. These two genera are the only ones alive today; the remainder are all fossils. The record of hyperamminids stretches back some way: specimens have been assigned to Saccorhiza from the Lower Carboniferous, while Hyperammina is recorded from as far back as the Lower Ordovician. Yep, that's a single genus that goes back nearly 500 million years (really makes you wish that meant something). The genus Platysolenites, if correctly placed within the hyperamminids, is one of the oldest of all forams, known from the very early Cambrian. The other genera are also Palaeozoic; one of them, Sacchararena, had a test made with fine white sand, leading to its name: 'sugar sand' (Loeblich & Tappan 1984).

REFERENCES

Kaminski, M. A. 2004. The Year 2000 classification of the agglutinated Foraminifera. In: Bubík, M. & M. A. Kaminski (eds) Proceedings of the Sixth International Workshop on Agglutinated Foraminifera. Grzybowski Foundation Special Publication 8: 237-255.

Loeblich, A. R., Jr & H. Tappan. 1964. Treatise on Invertebrate Paleontology pt C. Protista 2. Sarcodina, chiefly "thecamoebians" and Foraminiferida, vol. 1. The Geological Society of America and The University of Kansas Press.

Loeblich, A. R., Jr & H. Tappan. 1984. Some new proteinaceous and agglutinated genera of Foraminiferida. Journal of Paleontology 58 (4): 1158-1163.