19.01.19 - Kilby

On a very cold morning with the wind blowing straight from the Urals, I didn't fancy much more than a quick collecting trip so I consulted the map and decided that a short drive down to Kilby would fill in another tetrad. I grabbed a bag of leaf litter and was home again inside the hour, where, heating on, I sorted through it in the warm. It proved to be very productive, with Dicyrtomina saundersi, Entomobrya intermedia, Entomobrya nicoleti, Orchesella cincta, Orchesella villosa and Pogonognathellus longicornis all present. However, the main feature was a large number of very green isotomids:



The natural assumption was to assume that these were all Isotoma viridis, but I checked half a dozen of them and they were all Isotoma caerulea (two pairs of manubrial teeth plus dorsal macrosetae on manubrium A<B). This confirms my recent experience that it is not possible to distinguish between Isotoma anglicana/caerulea/viridis by habitus (general appearance) and that microscopic confirmation is required:




In amongst all the caerulea were two isotomids with a dark median band. Identifying these was a bit tricky as they had lost their macrosetae, but they turned out to be Isotomurus pseudopalustris (two characteristic pale dots either side of midline on abd4):