Posts Tagged ‘Family Gomphidae (Clubtails)’

Phanogomphus

April 20, 2017

Two teneral dragonflies were observed near Mulligan Pond during a photowalk at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. I was able to photograph the first one I spotted; the second flew away as soon as I approached it.

This dragonfly is either Ashy Clubtail (Phanogomphus lividus) or Lancet Clubtail (Phanogomphus exilis). Based upon the short, faded yellow markings on the dorsal side of abdominal segments eight and nine (S8-9), this individual is probably an Ashy Clubtail dragonfly. Less reliably, the 18 April date of the spotting also suggests Ashy Clubtail (for Northern Virginia).

18 APR 2017 | JMAWR | Ashy Clubtail or Lancet Clubtail (female)

Both Ashy- and Lancet Clubtail dragonflies were formerly classified as members of the genus Gomphus. Both species were reclassified recently as Phanogomphus. In the world of taxonomic classification, there are “lumpers” and “splitters.” Score one for the splitters!

Notice the first photo shows the wings folded above the abdomen. I spotted the teneral dragonfly when it flew toward me from the pond shoreline. The dragonfly rested in this location for a few minutes before it flew to a new spot (shown below) where it perched briefly with its wings unfolded. The last time I saw the dragonfly, it was flying toward the forest alongside the pond.

The other teneral dragonfly that I saw — “the one that got away” — was perched on the lawn near the walking path around the lake; it flew toward the forest when I moved closer to take some photographs.

18 APR 2017 | JMAWR | Ashy Clubtail or Lancet Clubtail (female)

(See a full-size version of the original photo, without annotation.)

This specimen is a female, as indicated by her rounded hind wings and terminal appendages.

All female dragonflies have two cerci (superior appendages); in contrast all male dragonflies have two cerci and one epiproct (inferior appendage), collectively called “claspers.” Contrast the appearance of the terminal appendages of this female Ashy Clubtail with a male of the same species.

The last photo in the set is a wider view that shows how well-camouflaged the dragonfly was perched on the lawn around the pond.

18 APR 2017 | JMAWR | Ashy Clubtail or Lancet Clubtail (female)

The Backstory

I was surprised to discover a Lancet Clubtail dragonfly near Mulligan Pond during late-June 2016. Knowing that Ashy Clubtails can be found in the same habitats preferred by Lancet Clubtails, I decided to look for Ashy Clubtails at Jackson Miles Abbott Wetland Refuge beginning in mid-April 2017. Apparently Mulligan Pond is a good place for both species, because I spotted two Ashy Clubtails the first time I went looking for them. Ah, if only odonate hunting were always so easy!

Copyright © 2017 Walter Sanford. All rights reserved.

Common Sanddragon dragonfly (male)

March 29, 2017

As you might expect, Common Sanddragon dragonflies (Progomphus obscurus) commonly perch on the sandy banks of small woodland streams. Not this one!

A Common Sanddragon was spotted perching on the vegetation growing alongside a manmade concrete drainage ditch that flows into Dogue Creek, Wickford Park, Fairfax County, Virginia USA.

This individual is a male, as indicated by his terminal appendages. Like all male clubtail dragonflies, the hindwings of male Common Sanddragons are “indented” near the body. This distinctive field marker is shown well by the last photo in this gallery.

Copyright © 2017 Walter Sanford. All rights reserved.

Malformed Cobra Clubtail dragonflies

February 21, 2017

I took 255 photographs during my first photowalk along the Potomac River at Riverbend Park, Fairfax County, Virginia USA, including lots of photos of Cobra Clubtail dragonflies (Gomphurus vastus). I noticed several malformed individuals when I reviewed the entire photo set recently (in search of look-alike species of clubtail dragonflies). None of the malformations prevented the dragonflies from functioning normally.

The first Cobra Clubtail is a male with a slightly crimped right hind wing, where a small part of the wing failed to fully inflate during emergence.

The next individual is a female. Notice that abdominal segment seven (S7) was crimped during emergence. (All dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.)

The last individual is a male. Notice his left front leg is missing. The male is either malformed or he lost the leg due to injury.

A Cobra Clubtail dragonfly (Gomphurus vastus) spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is a male; its left front leg is missing. Two dark face bars are field markers that can be used to differentiate Cobra Clubtail from other similar looking species of clubtails.

16 MAY 2016 | Riverbend Park | Cobra Clubtail (male, missing leg)

Two thick dark face bars are field markers that can be used to differentiate Cobra Clubtail from other similar looking species in the Family Gomphidae (Clubtails): Midland Clubtail (Gomphus fraternus) has no face bars; Splendid Clubtail (Gomphus lineatifrons) has thin dark face bars.

Tech Tips:

Shutter Priority mode was used for the first two photographs. Aperture Priority mode was used for the last photo, in order to increase the depth of field. As you can see, the depth of field at f/7.1 was insufficient for the tip of the dragonfly abdomen to be in focus. Typically, I wouldn’t publish the last photo, but I made an exception because it is the only photo I took that shows the face bars clearly.

Copyright © 2017 Walter Sanford. All rights reserved.

Russet-tipped Clubtail dragonflies (males, eating)

February 13, 2017

Two Russet-tipped Clubtail dragonflies (Stylurus plagiatus) were spotted during photowalks at Mulligan PondJackson Miles Abbott Wetland Refuge (JMAWR). Both individuals are males, as indicated by the large russet-colored club at the end of their abdomen, “indented” hindwings (see annotated image), and their terminal appendages.

Members of the genus Stylurus are known as “Hanging Clubtails” because they usually perch hanging vertically from trees, unlike most other species of clubtails that perch horizontally on the ground.

Most of them spend much time in flight over water, leading to speculation whether species of this genus may feed in flight rather than from a perch like most other clubtails. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6127-6128). Princeton University Press. Kindle Edition.

Both of the male Russet-tipped Clubtails featured in this post were observed feeding from a perch in a tree, although a sample size of two may be insufficient for drawing a meaningful conclusion.

22 September 2016

The first individual is eating a Multicolored Asian Lady Beetle (Harmonia axyridis) .

A Russet-tipped Clubtail dragonfly (Stylurus plagiatus) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating a Multicolored Asian Lady Beetle (Harmonia axyridis).

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

The next photo is my favorite in the set. The color, clarity, and composition combine to create a beautiful canvas for conveying the brutality of the eat-or-be-eaten natural world.

A Russet-tipped Clubtail dragonfly (Stylurus plagiatus) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating a Multicolored Asian Lady Beetle (Harmonia axyridis).

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

The last photo was shot using Aperture Priority mode in order to achieve maximum depth of field.

A Russet-tipped Clubtail dragonfly (Stylurus plagiatus) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating a Multicolored Asian Lady Beetle (Harmonia axyridis).

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

27 September 2016

The last individual is eating an unknown species of winged insect.

A Russet-tipped Clubtail dragonfly (Stylurus plagiatus) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating an unknown winged insect.

27 SEP 2016 | JMAWR | Russet-tipped Clubtail (male, eating)

Copyright © 2017 Walter Sanford. All rights reserved.

Stylurus spiniceps exuvia

January 6, 2017

I’ve never seen an adult Arrow Clubtail dragonfly (Stylurus spiniceps). That’s not surprising, since many experienced odonate hunters classify them as uncommon to rare.

But I know a place along the Potomac River in Fairfax County, Virginia USA where I am certain Arrow Clubtail dragonflies live. How do I know? Because I collected a Stylurus spiniceps exuvia from that location. In a nutshell, this is one of many reasons I’m learning to identify odonate exuviae.

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

No. 1 | 04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia)

A two-step process was used to identify the genus and species of the specimen.

Family

First, determine the family of the specimen. For reference, watch the excellent Vimeo video, Identifying dragonfly larva to family (8:06). Here’s the decision tree I used to identify the exuvia as a member of the Family Gomphidae (Clubtails).

  • The specimen has a flat labium that doesn’t cover the face (not mask-like), as shown in photo No. 2 and 3.
  • Antennae are club-like (not thin and thread-like, as in Aeshnidae).
  • Eyes not exceptionally large compared to the size of the head (not large, as in Aeshnidae).
An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

No. 2 | 04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, face-head)

(See a full-size version of the original photo, without annotation.)

Genus and species

Gomphidae is the second largest family of dragonflies, so it can be challenging to identify some specimens to the genus and species level. As it turns out, Arrow Clubtail exuviae are easy to identify because their abdominal segment nine (S9) is unique among Gomphidae: S9 is more than twice as long as it is wide at its base, as shown in the following annotated image.

The length of the exuvia is approximately 4.2 cm (~1.7 in).

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

No. 3 | 04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, ventral)

(See a full-size version of the original photo, without annotation.)

More photos of the exuvia are shown below.

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

No. 4 | 04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, dorsal)

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

No. 5 | 04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, dorso-lateral)

Tech Tips:

The following equipment was used to shoot all of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for manual focus) plus a Kenko 20mm macro automatic extension tube; Canon 580EX II external flash, off-camera, in manual mode (Master); Canon 580EX external flash, off-camera, in manual mode (Slave); and a coiled six-foot Vello Off-Camera TTL Flash Cord for Canon Cameras. A Raynox DCR-250 close-up filter was used for Photo No. 2.

Adobe Photoshop CC 2017 was used to annotate selected images.

Related Resources:

dichotomous key: a key for the identification of organisms based on a series of choices between alternative characters. Source Credit: Merriam-Webster Dictionary.

In long form, the decision tree is as follows (assuming the convention of labeling the two branches of each dichotomy as “a” and “b”, e.g. 1a, 1b, etc.):

p. 17, Key to the species of the genus Stylurus
1a – Abdominal segment 9 twice as long as wide at base. (spiniceps)

Editor’s Note: This is the 1,000th post on my photoblog. That’s a major milestone, and quite candidly, one I never expected to reach. Who knew I have so much to show-and-tell?

Copyright © 2017 Walter Sanford. All rights reserved.


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