Part 1 tells the story of 3 hours in the field with Chris Owen and Dave Gibbs. This story begins at the microscope a week later, keying out some millipedes from the beech wood.
Firstly, by sieving just a couple of handfuls of leaf-litter, I not only found Lithobius tricuspis (which is what I was after) but 30 or more small whitish millipedes. They must be very abundant at this site. I pooted 11 to give myself a good chance of getting an adult male, and Dave took a few as well. I guessed they were a species of Melogona in the field but under the microscope it was clear they had blunt paranota (bumps at 10 o’clock and 2 o’clock) on the body segments rather than being smoothly cylindrical. Unfortunately they were all immature so I put them aside and moved on.
Secondly, I had found a single specimen of what I thought was Craspedosoma rawlinsii under a log. I’d called Dave and Chris over to see it before pooting it for later checking. As well as being one of the few species with blunt paranota, and quite a strikingly patterned species, C. rawlinsii is quite a scarcity, occurring in wet, shaded habitats. There were loads of the little whitish immatures under the same log so I guessed they were the same species.
That “Craspedosoma rawlinsii” turned out to be an adult male. It keyed out as Craspedosoma rawlinsii but the gonopods and paragonopods (the highly modified 8th and 9th pair of legs used in mating) looked completely different to the pictures. I only had two female rawlinsii in my collection for comparison but they were bigger animals (my Bargoed specimen is just 10 mm long) and clearly different in other respects. What else could it be? It clearly wasn’t Nanogona polydesmoides and I could rule out Anthogona britannica and Anamastigona pulchella from the gonopod illustrations in BMG Bulletin 12.
So I arrive at that “Eureka moment” – I’ve discovered a millipede new to Britain! But in reality, rather than leaping around my study punching the air, a large part of me is thinking I’ve probably just made some daft mistake – after all, I’m no expert when it comes to millipedes. It is time to seek advice. Next day, Steve Gregory confirmed it was something new to Britain and recommended asking Des Kime in France if he could put a name to it. Des replied straight away suggesting genus Rhymogona and that I send my photos to Jörg Spelda in Munich. Jörg too was incredibly prompt and helpful, and after I’d carefully dissected the specimen and photographed and sketched the gonopods and paragonopods, he was able to recognise it as Ceratosphys confusa Ribaut, 1955, currently regarded as a variety or subspecies of Ceratosphys amoena Ribaut, 1920. Time to punch the air!
Though it was brilliant that a pan-species listers’ field meeting had resulted in a first for Britain, and brilliant to get it named so quickly, I couldn’t help feeling gutted for Chris, who’d had a first for Britain pinched from right under his nose. But while all this was going on, Chris was busy returning the favour …
Chris recognised that those abundant whitish immature millipedes were not Ceratosphys amoena but ANOTHER millipede new to Britain! Something so mind-fryingly improbable that I hadn’t considered for a moment that they were anything other than immature Ceratosphys. I think only one millipede (Brachyiulus lusitanus) has been added to the British list from outdoors (i.e., excluding greenhouses) since 1996 so to turn up two firsts for Britain in one day is simply incredible!
By checking his reference specimens, Chris found that he’d seen both Ceratosphys amoena and “Chris’s millipede” a few times in his area but had identified them all as Craspedosoma rawlinsii, having never seen the true rawlinsii! He soon located some adult males and enlisted the help of Steve, Des and Jörg to try and name it. This one was more difficult and whereas we’d had a name for Ceratosphys amoena within a few days, this time we had to wait a couple of weeks. I even started to wonder whether “Chris’s millipede” could be new to science. After all, the Ghost Slug was discovered new to science in the same part of the world. Why not a millipede?
In the end, Des recognised “Chris’s millipede” from Steve’s drawings and photos as Hylebainosoma nontronensis Mauriès & Kime, 1999. So not new to science but quite a recently described species. Jean-Paul Mauriès has also seen the images and has written: “C’est magnifique de retrouver cette espèce au Pays de Galles!”
We’ll be writing a paper on these two millipedes new to Britain in due course. Chris has found both of them in several more sites since but also drawn a blank at a few other sites further afield: map here.
Keep an eye on the Pan-species Listing website for news of a return visit to the Valley of the Millipedes in 2015.