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The riddle of Schayer's slater, Spherillo misellus (Crustacea: Isopoda)
Invertebrata 20, July 2001

The first species in the crustacean suborder Oniscidea (Isopoda) to be based on a Tasmanian slater was Armadillo misellus Budde-Lund, 1885. Budde-Lund described it in Latin from a single specimen collected in Van Diemen's Land by 'Dom. Scheyer' and lodged in a Berlin museum. (Note that an English translation of the description, by Thomson (1893), contains some mistakes.) Later Budde-Lund (1904) transferred A. misellus to the genus Spherillo Dana, 1852, and updated the locality name to 'Tasmania'.

I have studied terrestrial isopods from 1956 onwards but I have not yet seen a slater which I can identify with certainty as S. misellus. The holotype of the species is no longer in Berlin. It may not have been returned from loan to Budde-Lund, who died before his isopod studies were finished. The original collecting locality might have been anywhere in Tasmania so the chances of learning more about S. misellus seemed remote.

Recently, however, I learned that Adolphus Schayer, from Berlin, arrived in Tasmania in 1831 to work for the Van Diemen's Land Company. At first Schayer was based at Circular Head (now Stanley). From January 1835 to January 1843 he was Superintendent of the V.D.L. Company's station at 'Woolnorth', in Tasmania's northwest corner. Schayer collected many Tasmanian insects, and some crustaceans, before he returned to Berlin. It seems likely that Budde-Lund's 'Dom. Scheyer' was Superintendent Schayer and that his specimen of S. misellus was found in far northwestern Tasmania.

Among the Tasmanian Armadillidae, Cubaris tamarensis Green, 1961, comes closest to Budde-Lund's S. misellus. C. tamarensis has been collected from the Furneaux Group, Swan Point (West Tamar), Hawley Beach and West Ulverstone (NW coast), three sites north of Sandy Cape and Hibbs Lagoon (west coast). Thus the far northwest corner of Tasmania is within the known range of C. tamarensis.

Although not supralittoral, C. tamarensis does live near the coast and is easier to find than most forest slaters. It has unusually long scale-setae, which might represent the pubescent dorsal surface noted by Budde-Lund for S. misellus. However, some other characters of C. tamarensis, especially structures on the first pereon segment, do not match Budde-Lund's account.

The genus Spherillo has had a confused history. A type species, selected recently, will help to solve some taxonomic problems. Spherillo species which are not compatible with the type need to be re-examined, S. misellus included. Budde-Lund's species does not belong in Cubaris Brandt, 1833, and C. tamarensis is not a typical Cubaris. What was actually collected near 'Woolnorth' by Superintendent Schayer?

The riddle of Schayer's slater waits to be solved.

Alison J.A. Green
Launceston TAS

Further information:

Budde-Lund, G. 1885. Crustacea Isopoda terrestria, per Familias et Genera et Species descripta. Hauniae.

Budde-Lund, G. 1904. A Revision of 'Crustacea Isopoda terrestria' with additions and illustrations. Parts 2 & 3, pp. 32-144. Copenhagen: H. Hagerup.

Thomson, G.M. 1893. Notes on Tasmanian Crustacea, with descriptions of new species. Papers and Proceedings of the Royal Society of Tasmania 1892: 45-76.

A little bit of the north is down south
Invertebrata 20, July 2001

Tasmania has long been regarded as a biological treasure trove, supporting an astounding range of species found nowhere else, many of which have survived the perturbations of climate change during the Pleistocene. The late Prof. V.V. Hickman, Professor of Zoology at the University of Tasmania, spent his research career hunting out peculiar arachnids and other invertebrates, and documenting the unusual fauna of the southern isle. He described a plethora of Tasmanian oddities including Plesiothele fentoni, a primitive mygalomorph spider, and Holarchaea globosa, a minute araneomorph spider whose closest relative occurs in New Zealand. Hickman's link with arachnids and Tasmania is indelibly forged - the large cave-dwelling spider Hickmania troglodytes, the sole member of the subfamily Hickmaniinae, bears his name.

Hickman was also responsible for the discovery of one of the most unusual of Tasmania's arachnids. It all started with his inclination for collecting in the Launceston region which is nestled amongst some lovely hills, many of which are still forested to this day. He collected some peculiar pseudoscorpions which he handed to a student for study. J.C.H. Morris found that one of them was a member of the family Pseudogarypidae, a peculiar pseudoscorpion family which previously had been found only in the northern hemisphere, with several extant species of Pseudogarypus in North America (particularly in the Appalachians and the Rocky mountains), and some extinct species of the same genus found entombed in amber deposits from the Baltic region. Pseudogarypids have yet to be found in any other part of the world, including mainland Australia. Morris named the Tasmanian species Neopseudogarypus scutellatus and noted that Hickman had collected it in the Launceston area (Morris 1948). My visits to Cataract Gorge in 1986 and 1989 revealed that the species could be found under large rocks in the drier portions of the gorge, normally on slopes with casuarina trees. Despite careful searching for over 20 years, I have not found any pseudogarypid in mainland Australia.

Many years after the discovery of pseudogarypids in Tasmania, I examined a pair of pseudoscorpions collected at Frodshams Pass in southern Tasmania by Ian Naumann and Josephine Cardale of CSIRO Entomology. They were totally different to any pseudoscorpion which I had ever seen from Australia, and it took much detective work to establish their identity. Finally, I found that they were extremely similar to members of the genus Syarinus (Syarinidae) which are found in the northern hemisphere across the U.S.A. and southern Canada and in northern Europe. However, I found sufficient morphological differences between the Tasmanian species and the northern ones to warrant the erection of a new genus, Anysrius, and a second species from northwest Tasmania was also described (Harvey 1998). Once again, Anysrius has not been found in mainland Australia, and it appears to be endemic to Tasmania.

The similarities between the distribution patterns of these two groups of pseudoscorpions is remarkable, with species in the Holarctic region and in Tasmania - but nowhere else. As these small, relatively fragile creatures are unlikely candidates for trans-oceanic dispersal it seems that their biogeography can be best explained by vicariance: the common ancestors of both groups were distributed on the ancient supercontinent Pangea, which broke apart during the Cretaceous. The separate fragments took with them the biota of the time. It seems that the precursors of Neopseudogarypus and Anysrius ended up in the southern fragment, Gondwana, and have only managed to survive in isolated pockets of Tasmania. Whilst they may eventually be found in other southern areas (mainland Australia, New Zealand, South America or southern Africa), the only known stronghold of these small southern representatives of an otherwise northern group is in Tasmania - two truly remarkable cases of relictual endemism.

I would be happy to examine Tasmanian pseudoscorpions, especially if somebody can uncover further populations of either Neopseudogarypus or Anysrius.

Mark S. Harvey
Department of Terrestrial Invertebrates
Western Australian Museum
Francis Street
Perth WA 6000
mark.harvey@museum.wa.gov.au

Further information:

Harvey, M.S. 1998. Pseudoscorpion groups with bipolar distributions: a new genus from Tasmania related to the Holarctic Syarinus (Arachnida, Pseudoscorpiones, Syarinidae). Journal of Arachnology 26: 429-441.

Morris, J.C.H. 1948. A new genus of pseudogarypin pseudoscorpions possessing pleural plates. Papers and Proceedings of the Royal Society of Tasmania 1947: 43-47.

Happily bugged
Invertebrata 20, July 2001

To celebrate National Science Week the Burnie Library organised a 'Bug Us at the Library' morning on Saturday, 5th May. 'Bring your garden bugs, insects and creepy crawlies', said the publicity material, 'to be identified by experts', namely the authors of this note. When the day arrived neither of us was feeling particularly expert. We rolled up to the Library laden with reference books, CSIRO Entomology posters and pinned specimens. Who would come, and with what? To soothe our nerves the Library staff administered large cups of tea and heaping platefuls of cake and biscuits. Staff had also organised two long tables for us at which to meet clients, and had made up their own bugs display of books from the lending collection.

It wasn't too bad. We had 14 interviews in two hours with North-West Coasters from Wynyard to Penguin. The tally of bugs (in order of appearance) was:

1 theridiid spider (the redback look-alike without the stripe)
2 Fuller's Rose Weevils, Asynonychus cervinus
1 Cabbage White larva, Pieris rapae
1 arctiid moth
2 spirosteptidan millipedes (natives)
1 land snail, Helicarion cuvieri
1 clubionid spider
1 gnaphosid spider
several talitrid landhoppers
1 stink bug
1 lycosid and 1 salticid spider
1 tree lucerne moth, Uresiphita ornithopteralis
1 mole cricket, Gryllotalpa sp.
3 sugar ants, Camponotus sp.
1 anthelid moth larva, Anthela sp.
1 daddy-longlegs spider, Pholcus phalangioides
numerous spotted millipedes, Blaniulus guttulatus (in a strawberry)
1 Portugese millipede, Ommatoiulus moreleti (in the same strawberry)
1 theridiid spider and 1 ?gnaphosid spider
1 psychid moth larva
2 burrowing crayfish, Engaeus fossor
several ?Argentine ants
1 leaf-curling spider, Phonognatha sp.

We were also told about a large stick insect, a praying mantis, Emperor Gum Moths, introduced bumblebees at Ridgley and a fast-running spider (almost certainly Supunna sp.).

Of the 14 interviews, seven were with young children and their parents. We did our best to encourage the kids and to suggest that bug study was rewarding and interesting. It was a bit harder to get this message across to the adults who had come with 'How do I get rid of this?' inquiries.

We enjoyed the morning and wouldn't mind repeating the exercise. The book we used most often with our clients was the excellent Backyard Insects (Paul Horne & Denis J. Crawford, Miegunyah Press, 1996). Next time, a reference collection of specimens would be a useful aid. Or maybe (in future) a website with images of, say, the 200 most-often seen suburban invertebrates...

Lionel Hill
Department of Primary Industry, Water and Environment
PO Box 303
Devonport TAS 7310
Lionel.Hill@dpiwe.tas.gov.au

Bob Mesibov
Research Associate
Queen Victoria Museum and Art Gallery
mesibov@southcom.com.au

A study of Astacopsis gouldi habitat in two rivers in northwest Tasmania:
summary of Honours research at the University of Tasmania
Invertebrata 20, July 2001

From August 2000 to January 2001, I studied how habitat parameters affect the population structure of Astacopsis gouldi Clark and the number of taxa and abundance of other aquatic macroinvertebrates. Reasons for the decline in populations of A. gouldi have been generally accepted to be over-fishing and habitat loss and degradation. However, changes in any one of the many variables of the riverine environment, either natural or as a result of human activity, can cause major changes in the composition of aquatic communities.

Six study sites were selected: paired sites in three distinct riparian environments. Two sites were intensively grazed pasture-land, two had mature pine plantation on one bank and native vegetation on the other, and the last pair were set within undisturbed native wet sclerophyll/mixed rainforest. The study sites, each ca. 500 m long, were located along two rivers in northwest Tasmania and were between 30 and 100 m above sea level. Vegetation composition, vegetation coverage and topography were recorded for each site. At each site I measured the population density and size range of A. gouldi and the abundance of a range of other aquatic macroinvertebrates. River water was tested for dissolved oxygen, pH, maximum and minimum water temperatures, nitrates, nitrites, phosphates, ammonium and conductivity. Physical conditions on-site and upstream were assessed. Site variables were then examined for correlations with population structure of A. gouldi and with the composition and abundance of the aquatic macroinvertebrate community generally.

Little correlation was found between populations of A. gouldi and water chemistry. However, a sharp spike in nitrate levels in September at all sites except site N2, where the largest population was found, invites further investigation. It was found that lobsters were not active below ca. 8°C and above ca. 18°C. In addition, few females were caught during January, suggesting a change in behaviour over this period.

Wide variation was found between sites in numbers of lobster captured. A cause for concern was that although over 200 lobsters were caught over the six-month study period, only five females were found to be in berry. Greater numbers of young lobsters were present at the more productive sites, but only low numbers of breeding-size females were found. Healthy populations of A. gouldi (with a wide range of sizes, including breeding size) were found at only one site (N2) where riparian vegetation was intact both at the site and upstream. One possible explanation for the healthy populations at site N2 is that its streamside trees are a source of organic matter in the form of leaves, twigs and logs for the rivers, and provide essential food and shelter for the lobster and other aquatic invertebrates. However both of the pine sites (P1 and P2) and the second native site (N1) offered these conditions but did not carry as high a population of A. gouldi.

The data suggest that where instream organic matter was not a limiting factor, the major influence of streamside vegetation on populations of A. gouldi was through the moderation of water temperature. Where large stretches of river were unshaded by trees upstream of sites, water temperature in summer was much higher than at those sites where upstream riparian vegetation was intact. Correspondingly, populations of the lobster were lower at sites where water temperatures were comparatively high, even where vegetation within the site was intact.

Figure 1 illustrates the difference in temperature range from site to site over the study period. The smallest range was found at the native site N2, where riparian vegetation both at the site and upstream was intact. Interestingly, the largest temperature range was at site N1, the second native site. This site had similar within-site conditions to site N2, but logging upstream had left the river exposed without a buffer zone for several kilometers. The two pine sites P1 and P2 also reflect the loss of an upstream riparian zone in their comparatively large temperature ranges. The rivers at the two farm sites F1 and F2, although both situated in open farmland with no riparian buffer zone, reinforce the importance of their upstream riparian vegetation by a reduction in overall mean temperature range.

Figure 2 shows the total biomass of lobsters caught at each site. Comparison of the biomass caught and the temperatures at each site, shown in Figure 1, suggest a relationship between populations and water temperature. Sites F2 and N2 represent the farm and native sites respectively on one river with little upstream disturbance, while sites F1 and N1 represent the farm and native sites respectively on a second river which has experienced major upstream disturbance within 3 km upstream of site N1.

The discovery of strong correlations between the presence of several families of aquatic invertebrates and presence of healthy populations of A. gouldi reinforced these findings. Where sites experienced increased water temperatures and loss of riparian vegetation, especially upstream of the site, populations of the lobster were low and populations of the correlated species of aquatic macroinvertebrate were either sparse or absent.

The results of this study have implications for land management, reinforcing the message that adequate riparian buffer zones need to be retained along streams. Land managers should also be aware that activities in the headwaters of streams will have an impact on downstream aquatic habitats, with an impact in particular on populations of A. gouldi, which is presently listed as vulnerable.

Joanna Lyall
B. App. Sc (Hons)
59 South Riana Road
Upper Natone TAS 7321

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