Sunday, October 22, 2017

A "Cheat Sheet" for pronggilled mayfly (Leptophlebiidae) genera


One more, and it's the easiest one to do.  With very little help -- this guide and a loupe -- monitors and volunteers should be able to determine pronggilled mayfly genera right at the stream.  Only one thing to check: the gills.  I've found four genera, and four types of gills.


A "Cheat sheet" for pronggilled mayfly (Leptophlebiidae) genera


 1. gills forked with tracheal branching at base: Neopleptophlebia

2. gills forked without tracheal branching at base: Paraleptophlebia

3. gills forked, each branch ending in a cluster of filaments normally 3 (look like pitchforks): Habrophlebia


4. each gill consisting of two petals (bilamellate) which end in a pointed filament: Leptophlebia
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1. gills forked with tracheal branching at baseNeopleptophlebia

They look like this.


And the gills are forked with tracheal branching.


While I can't say this for sure, I suspect that this is the genus that monitors most often see.  They're in our streams from late fall through much of spring (December - April?).  For fly fishermen, they hatch as "Blue Quills."  I see tons of them at the Rapidan River: look in the leaf packs.
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2. gills forked without tracheal branching at baseParaleptophlebia

Less common, typically in pretty small streams (though I find them as well at the Rapidan River).


(Also the nymph at the top of the page.)  Easy to see that the gills lack the "tracheal branching" we see on Neoleptophebia.


I've identified three species for this genera.  The one pictured here -- P. guttata -- is the most common.  This genera is one that I typically see from late spring into summer.
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3. gills forked, each branch ending in a cluster of filaments normally 3 (look like pitchforks): Habrophlebia



Really cool gills.  No mistaking this genus, and the gills are easy to see with a loupe (actually, you can see them with the naked eye.)  But, you'll have to be lucky to see one.  They're "uncommon": this is the only one that I've seen (Rapidan River).
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4. each gill consisting of two petals (bilamellate) which end in a pointed filamentLeptophlebia



Beaty says this genus is "widespread" ("The Ephemeroptera of North Carolina," p. 78), but to date this is the only one that I've seen (Doyles River at Brown's Cove).
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Easy-peasy.  Just have to find them.

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