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So my blog this time is concerning some work that I undertook recently at the South Australian Museum. I was over in Oz on a holiday, playing with wombats and wallabies in Tasmania,  and I thought that I would utilise the time in checking on some Cerdistus specimens which was a group of robberflies (Asilidae) that my associate Bob Lavigne, a retired Dipterist in the States, and I were working on.


We have recently published a paper on a new species and are currently working on a key. Bob used to live in South Australia and spent many years collecting this group of Asilids. There are many new species that he has described or is in the process of describing and so we decided that it was time to develope a good key to this group. I say group, as we are not sure whether all the previoulsy described Cerdistus belong in this genus - it may be split as well.


Cerdistus SPC Mated pair IMG_9305-9316 Fig. 1.jpg

These are some Cerdistus that were caught in cop and so we are very sure that we have a male and a female of the same species....Lovely looking things. As with all robberflies they have the fantastic mystax or moustache, which are very long stiffened bristles to prevent the flailing prey from damaging the delicate mouthparts!!


Bob and I were based at the South Australian Museum - and as always I have great fun pocking around in other peoples collections (it is like pocking around other peoples houses! - although you may get arrested for that....) - Everyone has a slightly different style although good management practices are universal. The collection in the South Australian Museum is looked after by just one Man! I am amazed at his workload and what he has achieved! But again he is assisted by a superb team of volunteers! Mostly retired, this team have done wonders with many different parts of the collection.


My most surprising event upon arrival was that Bob had kindly arranged accommodation for me through his colleague, a scientific associate at the museum, Archie MacArthur. Now I did not think much of the name till I arrived and I was pounced upon by this man who remembers me coming into the collection 17 years ago to ask for help in identifying ants!! I struggle to remember last week let alone that long ago….and to make matters worse his 90th birthday was whilst I was there…I was utterly shamed!!! He even produced a piece of paper with my scribbled notes over it. (I undertook a placement whilst at the University of Adelaide – months running around the outback looking for ants….not to be sniffed at!!)


He is still publishing and one more book is just in print (e.g.


Here he is celebrating his birthday!



And here is one of 'the boys' - please pay no attention to the wine on the table they were just props....

archie and bob.jpg

But back to flies. Bob had been travelling to many of the major collections in the world to look at the type holdings for this group of flies. Whilst in the UK on a previous visit he had spent time in Oxford as well as in the NHM imaging the specimens. I have been working on a descriptions spreadsheet noting individual characters of NHM specimens and he has been working on them, as well as the Oxford material, material from Paris and of course, the main bulk of the material in the SA Museum.



If you leave Dipterists alone for any period of time they start obsessing over genitalia. Bob spent a lot of time finding original descriptions of Type species, making copies of the diagrams where there were any and then photographing the genitalia. (I have a large collection... )


Cerdistus SPCR-Cropped Fig 2.jpg

See how wonderfully shiny it is!


So the plan for the week was to go through the working key with the majority of the specimens in front of me. Now making a key is not easy and Bob had done an amazing job so far in getting as far as he had. Most of the key was written from his (and some of my) notes from specimens. However, It is still amazing how many times they do not fit or something has been recorded incorrectly or with a level of ambiguity as to make writing for a key difficult!! When I was going through the key there were stumbling blocks all over the place (resulting in a bit of a potty mouth)– and much

of that was due to me!! I am always a big believer in simple things – if you are going to describe something – why not have an image to clarify exactly what you mean.


However, this means lots of images as there are many characters on the fly that we use in speciating them – the colour of their moustache for instance (it is a key feature of the robberflies). I have pages and pages of notes for images that I have to now take as well as verifications that i have to do. I have had to bring back a box of flies to the UK to enable me to again compare with the specimens in the NHM.


Box of flies - always amusing to take as hand luggage on a plane - very confused customs people...airline staff...people sitting next to you...



As well as working on the morphology of the specimens we are about to sequence them. This will greatly help us decide if what we think is a new species is in fact a new species, or is it just a colour variant of another one. When you have very few of a ‘morpho’ type you need to gather as much evidence that it is a new species. Our collection in the NHM is dotted with singletons and it is not uncommon to describe on a single specimen although this does not aid us in understanding any variation within the species. Now as we think that there are many many new species to this group (and as already stated, we do not believe that it is even one genus) by enlisting both morphological and molecular analyses we are formulating the best picture.


So come back to us in about 6 months when we have gone through the analyses, described the new species, and properly developed the key. In the meantime, check out some of the UK species of Asilidae. I love this group as they are just the best predators!!


And just to show you how much we love our work - this was my Christmas card from Bob!!! Beautiful isn't it!

Cerdistus Belair  MS IMG_0416-0425 Chr.jpg

Erica McAlister

Member since: Sep 3, 2009

I'm Erica McAlister, Curator of Diptera in the Entomology Department. My role involves working in the collection (I have about 30000 species to look after and over a million specimens), sometimes in the lab, and thankfully sometimes in the field.

View Erica McAlister's profile