Posts Tagged ‘Epitheca costalis’

When I photographed this dragonfly on Friday at Occoquan Bay National Wildlife Refuge, I had no doubt in my mind that it was a Common Baskettail dragonfly (Epitheca cynosura).  I had seen dragonflies of this species several times near that area of the refuge, including once earlier this year. Besides, what else could it be?

I got a quick response to that question when I posted a photo to the Virginia Odonata group, a Facebook forum devoted to dragonflies and damselflies. One viewer suggested that it looked more to him like a Slender Baskettail dragonfly (Epitheca costalis) than a Common Baskettail. Eventually several experts weighed in and also opined that it looked like a male Slender Baskettail, though one acknowledged that it was difficult to make a definitive call based on my photos that he judged to be “suboptimal.”

So how do you tell the species apart? Slender Baskettails tend to have a narrower waist and are relatively slimmer, but the only way to know for sure is by the length of the cerci, the dark black terminal appendages at the tip of the abdomen (the “tail”). The cerci are longer on male Slender Baskettails than on Common Baskettails. (If you want to know more about dragonfly terminal appendages, check out a posting by fellow dragonfly enthusiast Walter Sanford entitled Dragonfly terminal appendages (male, female).)

The folks who suggested that this dragonfly is a Slender Baskettail did so on the basis of my photos, but that is not really a reliable method, because the angle and lighting can distort perceptions. How do you know for sure? One expert stated that “you can really only ID them by measuring the cerci which I do of a specimen under a microscope.” I may be a little geeky when it comes to dragonflies, but I am not about to measure a specimen’s anatomical parts with a microscope.

I am left therefore with a bit of a scientific mystery. Is it a Slender Baskettail or a Common Baskettail dragonfly? It might be a bit of heresy to some, but it does not really matter to me. I was simply happy to capture these cool photos of a beautiful creature.

Shakespeare’s words about a rose in “Romeo and Juliet” could easily be applied here, “A rose (or a dragonfly) by any other name would smell (or look) as sweet.”


Slender Baskettail

Slender Baskettail

© Michael Q. Powell. All rights reserved.




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