Pot o’ Emeralds

The following photo shows a plastic container of 20 Downy Emerald dragonfly (Cordulia aenea) exuviae, collected by a good friend during April 2018 in Vienna, Austria. Not a pot o’ gold at the end of a rainbow, but valuable treasure nonetheless!

Thanks to field marks shared by Benoit Guillon, I was able to quickly determine that all of the exuviae are the same species as the specimen featured in a recent blog post.

Benoit’s excellent Web pages are written in French. I used the Google Chrome Web browser to translate French to English.

The exuvia of the Tanned Cordulia is easy to recognize, provided you have good eyes or … a magnifying glass. It is indeed only to present a line, or double black line, on the thorax, clearly visible on the enlargement of the photo on the top left [see Benoit’s Web page]. She also has very large legs and we easily notice the teeth of the palps of her [face] mask in the photo above [see Benoit’s Web page]. As for his eyes, even if they are spectacular [sic?], some other odonate varieties are also strange. Source Credit: Benoit Guillon.

The key field marks — shown in the following focus-stacked composite image — include one- or two dark lines along the thorax, and a dark line between its small, pointy eyes.

Related Resource: Cordulia aenea: exuviae (1/2), by Benoit Guillon.

Tech Tips

I used my Panasonic Lumix DMC-FZ150 superzoom camera and a handheld Canon 580EX Speedlite fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier to shoot the first photo featured in this blog post.

The following equipment was used to shoot all of the photographs for the focus-stacked composite image, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier. Adobe Photoshop CC 2017 was used to create the focus-stacked composite image, as well as spot-heal and sharpen the final output.

Copyright © 2018 Walter Sanford. All rights reserved.

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3 Responses to “Pot o’ Emeralds”

  1. Mike Powell Says:

    Wow. It is definitely cool to see so many exuviae together in a single shot. What I find most unusual is that there was a single exuvia of another species intermixed with all of those of those Downy Emerald exuciae. I guess that means it is good to collect all of the exuviae you can find and not worry about identification until later.

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