Friday, November 17, 2017

Checking the Rapidan River

Yesterday I went up to the Rapidan River to check on the flow and habitat conditions.  The good news is that the water levels are normal again: the bad news is that the leaf packs have not decomposed to the point where there are large numbers of nymphs in them chomping away.  Still, I got some pretty nice photos.

1) Above and below, the uncommon, "common stonefly" (Perlidae) Agnetina capitata.  As you can see from the posterior edge of the wingpads this one was far from mature.   For that we have to wait until June and July.

2) The "brushlegged mayfly" (Isonychia sp.).   These were quite common.

You might recall that I was hopeful that, using our new key, I could get these down to species ID.  But alas, every nymph that I've found so far has a "cluster of filaments" for forecoxal gills -- these

-- which means that I can't go any further: I'd need an electron microscope.

3) And the other thing that was common in the leafpacks was the pronggilled mayfly, Neoleptophlebia.  They were probably N. assimilis, but they're still too small for me to attempt to confirm that ID.


Sure good to see water again in our streams.  The season's about to pick up.

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