05.01.19 - Gilmorton - Mottes and Moats

We celebrated our impending return to work (!) by a quick trip down to Gilmorton. In spite of constant grey skies and not having seen the sun for days, the ground was quite dry and at first, with the leaf litter all crispy, I began to think we wouldn't find much. But Gilmorton has a secret weapon - a Norman motte surrounded by a moat. Technically the moat is dried up (apart from a section which has been turned into a garden pond), but that's dried up in the sense of not actually underwater - it was quite squishy in the bottom and full of Sweet Chestnut leaves. Immediately we began to find springtails, notably quite a few Dicyrtomina minuta, which shone out in the gloom:



However, what caught my eye were lots of Isotomids. When I got these home for a closer look most of them looked like Isotoma viridis, and indeed that's what they turned out to be under the microscope, with a single tooth on the apical edge of the manubrium:



However, several specimens were larger and much darker that the "normal looking" I. viridis in the sample and I strongly suspected these might be Isotoma anglicana:



I spent a long time working on these but because of my lack of microcopy skills I was not able to confirm these as anglicana because I couldn't see any definite evidence of two manubrial teeth, so reluctantly, I had to put these down as one of the ones that got away. I am very cautious of confirming the identity of the Isotoma anglicana/viridis species pair because we know that these have been so frequently confused in the past.




Also present on the site at the bottom of a big leaf pile which was nice and damp at the bottom were Dicyrtomina saundersi, Orchesella villosa and Pogonognathellus longicornis (but no Orchesella cincta). All in all, probably the best afternoon I've ever spent grubbing around in the bottom of a Norman moat (n=1).