New discoveries in 2016

The more you know, the more you know how much you don’t know. Huh? There’s always more to discover/learn! My new discoveries in 2016 are presented in reverse-chronological order.

Eastern Amberwing dragonfly exuviae

Perithemis tenera exuviae, published on 06 December 2016.

07 JUL 2016 | Potomac River | Eastern Amberwing (exuvia, head-on)

I’m a man on a mission to demystify the art and science of odonate exuviae identification. The task is as challenging as I was led to believe, but with determination and persistence it is do-able.

The specimens featured in this post are the first odonate exuviae that I was able to identify to the species level. Although the specimens were collected in early July, they were identified in early December. New species will be added to my Odonate Exuviae page when their identity is confirmed.

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Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR) is a familiar location where several species, previously unknown to occur at the park, were discovered in 2016.

Shadow Darner dragonfly

Shadow Darner dragonfly (female), posted on 18 October 2016.

14 OCT 2016 | JMAWR | Shadow Darner (female heteromorph)

Russet-tipped Clubtail dragonfly

Russet-tipped Clubtail dragonfly (male), posted on 26 September 2016.

22 SEP 2016 | JMAWR | Russet-tipped Clubtail (male)

Blue-faced Meadowhawk dragonfly

Another new species discovered at JMAWR, posted on 20 September 2016.

15 SEP 2015 | JMAWR | Blue-faced Meadowhawk (female andromorph)

Lancet Clubtail dragonfly

Identifying clubtails by the calendar, posted on 30 June 2016.

26 JUN 2016 | JMAWR | Lancet Clubtail (male)

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In addition to my contributions to the odonate species list at Jackson Miles Abbott Wetland Refuge, Mike Powell discovered the first official record of Swift Setwing at JMAWR and in Fairfax County, Virginia USA.

Copyright © 2016 Walter Sanford. All rights reserved.

Identifying clubtails by the calendar

Much to my surprise, a Lancet Clubtail dragonfly (Gomphus exilis) was spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA. This individual is a male, as indicated by his terminal appendages.

26 JUN 2016 | JMAWR | Lancet Clubtail (male)

Ashy Clubtail (Gomphus lividus) and Lancet Clubtail (Gomphus exilis) are two species of dragonflies from the Family Gomphidae (Clubtails) that are similar in appearance.

26 JUN 2016 | JMAWR | Lancet Clubtail (male)

Kevin Munroe, author of the excellent Dragonflies of Northern Virginia Web site, explains how to identify Ashy Clubtail versus Lancet Clubtail on the page for Ashy Clubtail (see the section entitled “Notes from the field”). In this case, item No. 5 explains how to use a calendar to differentiate the two species.

Lastly, use the calendar: April = Ashy Clubtail; June or July = Lancet Clubtail; May = could be either one. (These dates work in Northern Virginia.) Source Credit: Ashy Clubtail, by Kevin Munroe.

Since the specimen shown in the preceding photographs was spotted on 26 June, Lancet Clubtail is almost certainly the correct identification. Further, the physical characteristics described in item No. 3 on Kevin’s checklist confirms what the calendar tells us.

Copyright © 2016 Walter Sanford. All rights reserved.

Can I see some eye-dentification?

It may seem like all dragonflies look alike when you’re beginning to learn how to identify dragonflies. For example, all dragonflies have large, multifaceted compound eyes. Look closely. Careful observation of the color, shape, and size of eyes should enable you to quickly identify the family (or families) of dragonflies to which a specimen may belong.

The following field markers — used in combination with a good field guide to dragonflies, a species list for your location, and the process of elimination — should enable you to identify unknown specimens more quickly than randomly trying to find a match between your specimen and one of the 316 of species of dragonflies known to occur in the United States!

Clubtail Family (and Petaltail Family)

The eyes of clubtail dragonflies (and petaltails) are widely separated, somewhat similar to the eyes of damselflies. The Clubtail Family is the second largest family of dragonflies, so this field marker should be useful for identifying a lot of dragonflies to the family level — if only clubtails were as easy to identify down to the species level!

09 MAY 2013 | Meadowood Recreation Area | Ashy/Lancet Clubtail (female)

The preceding dragonfly is either an Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphis exilis). Ashy- and Lancet Clubtail dragonflies are similar in appearance and difficult to differentiate with complete certainty. But one look at those eyes and you know it’s definitely some species of clubtail!

Spiketail Family

Notice the eyes of the following dragonfly nearly touch at a point between its eyes — that’s a distinctive field marker for the Spiketail Family.

09 MAY 2013 | Meadowood Recreation Area | Brown Spiketail (female)

Cruiser, Emerald, and Skimmer Families

In a few families of dragonflies, the eyes meet along a short seam near the face.

The Skimmer Family is the largest family of dragonflies. Many species of Skimmers are common and fairly easy to identify.

There are fewer species of dragonflies in the Cruiser Family than the Skimmer Family; no other dragonflies in the United States look similar to cruisers.

02 MAY 2013 | Accotink Bay Wildlife Refuge | Stream Cruiser (male)

Many species of the Emerald Family feature distinctive bright green eyes, hence the family name.

25 JUL 2012 | The Wildlife Sanctuary | Mocha Emerald (male)

Darner Family

The eyes of Darners meet along a long seam from front-to-back.

14 AUG 2012 | Huntley Meadows Park | Common Green Darner (mating pair)

Self-test

OK, let’s apply what you just learned. Looking at the eyes only, can you identify the family for the following dragonfly? If you would like to know whether your answer is correct, then please leave a comment.

Teacher’s Note: In order to avoid revealing the answer to the one-question quiz as soon as the first person comments, I changed the settings for this blog so that comments must be approved manually.

26 JUN 2015 | Wickford Park | [Insert family name here.]

Editor’s Notes: This post is adapted from Dragonfly Head & Eyes, one of many excellent guides on the Odes for Beginners Web site. Thanks for the inspiration, Sheryl Chacon!

Copyright © 2015 Walter Sanford. All rights reserved.

Ashy- or Lancet Clubtail dragonfly (redux)

The following photographs show a Clubtail dragonfly perching on the ground along the earthen dam at Hidden Pond, a small lake located at Meadowood Recreation Area in Fairfax County, Virginia USA. This individual is either an Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphis exilis). Ashy- and Lancet Clubtail dragonflies are similar in appearance and difficult to differentiate with complete certainty. Anyone care to offer an expert opinion?

Editor’s Note: According to Ed Lam, author and illustrator of Damselflies of the Northeast, this individual is definitely female but the species is indefinite.

In the pictures where the abdomen tip is obscured, the rounded shape of the base of the hind wing identifies it as a female. Not going to guess on the … [species]. That’s the way it goes sometimes.

Thanks for your help, Ed!

Copyright © 2013 Walter Sanford. All rights reserved.

Ashy- or Lancet Clubtail dragonflies

I spotted a couple of Clubtail dragonflies along the trail to Hidden Pond, a small lake located at Meadowood Recreation Area in Fairfax County, Virginia USA. These dragonflies are either Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphis exilis). Ashy- and Lancet Clubtail dragonflies are very similar in appearance and difficult to differentiate with complete certainty. I think both individuals are female, based upon their terminal appendages. Can I get an expert second opinion?

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

• Genus Gomphus | Gomphus lividus | Ashy Clubtail | male | top view
• Genus Gomphus | Gomphus lividus | Ashy Clubtail | male | side view
• Genus Gomphus | Gomphus lividus | Ashy Clubtail | female | top view
• Genus Gomphus | Gomphus lividus | Ashy Clubtail | female | side view

Editor’s Note: According to Ed Lam, author and illustrator of Damselflies of the Northeast, both individuals are definitely female but the species is indefinite. Thanks for your help, Ed!

[Both photos] show females. The abdominal appendages are simple in form compared to males. … the rounded shape of the base of the hind wing identifies it as a female. What species they are is a tougher question. The pale Segment 9 on the female perched on the brown oak leaf suggests it is a Lancet but since Ashy can have that mark, Ashy can’t be ruled out. The female sitting on the ground ‘feels’ more like an Ashy, with limited abdominal markings, browner in appearance, eyes purple-er, but again, it can’t be confirmed from the picture alone. Ashy is usually larger and more brawny in appearance.

Remember that “Segment 9” refers to abdominal segment nine (of 10), numbered from front to back.

Copyright © 2013 Walter Sanford. All rights reserved.