[ID] Pygmy Woodlouse? 99% sure

Jason Green · #1 (**permalink**) 10-03-2010, 08:59 PM

Evening all,

I saw this Woodlouse today, under a half-submerged, moss-covered brick. I collected it in a specimen pot to photograph...

10/03/2010

Top-side, near side-on and rear-end.

It measured up at 3.5mm-ish, so I assume it's a juvenile. As for why I believe it is the Common Pygmy Woodlouse - it has the correct head pattern, general colouration, elongate profile and long rear uropods.

I wonder if I'm correct in my ID? All thoughts welcome. I know exactly where I saw it and plan on returning tomorrow.

Thanks for reading

Take care,

Jason

Fauna · #2 (**permalink**) 11-03-2010, 08:16 PM

Hi Jason...i agree with you here on common pygmy - Trichoniscus pusillus. Just had them in the garden along with others including the Rosy Woodlouse

Apparently T.pusillus exist in two forms T.pusillus form pusillus composed almost entirely of females and T.pusillus form provisorius composed roughly in equal numbers of both sexes.

Jason Green · #3 (**permalink**) 11-03-2010, 09:07 PM

Thanks Chris, that's a first for me - interesting info on the forms too. My 7th species now.

They are: Androniscus dentiger, Armadillium vulgare, Philoscia muscorum, Porcellio scaber, Porcellio spinicornis, Oniscus asellus and now Trichoniscus pusillus.

Any tips for others in general London habitats?

Fauna · #4 (**permalink**) 12-03-2010, 05:27 PM

Once you get your eye in on T.pusillus you will find that they turn up all over the place, they are all the pygmy woodlice i can seem to find. Except for the Rosy woodlouse that is...

Have a gentle rummage through some ants nests to try for Platyarthrus hoffmannseggi, you should also take a look at old dumping sites, one near me has 9 species with Armadillidium nasatum under nearly every stone. I'm not sure where else you should be looking in London, possibly old buildings and woodland i suppose.