Posts Tagged ‘Stenogomphurus rogersi’

Identification guides for Sable Clubtail

July 26, 2022

Identification guides for Sable Clubtail dragonfly (Stenogomphurus rogersii) were created for both adult and larva/nymph forms. (Remember, a well-preserved odonate exuvia is a perfect model of the final instar larva.)

Sable Clubtail has a limited range and is classified as rare to uncommon.

The adult flight period is from May 21 to July 24 in the Commonwealth of Virginia. Source Credit: “CHECKLIST OF THE DRAGONFLIES AND DAMSELFLIES OF VIRGINIA, April 2017 and April 2020 updates” by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage.

Adult

Apple macOS and Safari (interactive)

Apple macOS and “Safari” were used to convert the Web page version of “Field marks for identification of S. rogersii” to PDF (Portable Document Format). The PDF version of the same Web page is 351 KB, ad-free, and is interactive (with Internet access), meaning the embedded hyperlinks work as expected.

Apple iOS and Safari (non-interactive)

Apple iOS and “Safari” were used to convert the Web same page to PDF. The PDF version is 5.4 MB, ad-free, and is not interactive.

(See complete PDF version of “Field marks for identification of S. rogersii.”)

The preceding screenshot shows what the output looks like.

Apple “Photos” can be used to view PDFs on iOS devices. For macOS devices, Apple “Preview” can be used to open the complete PDF version; select “View / Actual Size” and resize the window as necessary. And of course PDFs can be opened using a Web browser.

Exuvia

Apple macOS and Safari (interactive)

Apple macOS and “Safari” were used to convert the Web page version of “Stenogomphurus rogersii exuvia” to PDF. The PDF version of the same Web page is 692 KB, ad-free, and is interactive (with Internet access).

Apple iOS and Safari (non-interactive)

Apple iOS and “Safari” were used to convert the Web same page to PDF. The PDF version is 4.8 MB, ad-free, and is not interactive.

(See complete PDF version of “Stenogomphurus rogersii exuvia.”)

The preceding screenshot shows what the output looks like.

Copyright © 2022 Walter Sanford. All rights reserved.

Burrowing hooks

October 12, 2021

Odonate nymphs (larvae) can be classified broadly into three (3) groups: Burrowers; Climbers/Clingers; and Sprawlers. Source Credit: “Conservation of Illinois: Dragonflies” Webinar (1:17:19) by Marla Garrison, McHenry County College.

Some species of nymphs (larvae) in Family Gomphidae (Clubtails) are burrowers that have an anatomy adapted for burrowing into sandy substrates quickly, including a torpedo-shaped body and thick legs with burrowing hooks.

Pop Quiz: Using the preceding annotated image as a guide, can you find the burrowing hooks on the front- and middle legs of the following specimen?

Related Resources

The following videos from the Dragonfly Society of the Americas show two species of clubtails burrowing into sand. Thanks to Marla and Carlos Garrison for sharing these videos via YouTube. Both videos are hyperlinked from “The Search Begins” by Marla Garrison and Ken Tennessen (Argia, Volume 33, Issue 3).

Common Sanddragon (Progomphus obscurus)

Riverene Clubtail (Stylurus amnicola)

Copyright © 2021 Walter Sanford. All rights reserved.

Sable Clubtail dragonfly (male, No. 2)

July 10, 2020

A Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted by Michael Powell during a photowalk at a location in Fairfax County, Virginia USA. This individual is a male, as indicated by his “indented” hind wings, and terminal appendages.

Look at the blade of grass on which the Sable is perched. Notice the “leftovers” from an afternoon snack eaten by the dragonfly before the photo was taken.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

Male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”); and a lower unpaired epiproct (“inferior appendage”). The epiproct for Sable Clubtail is essentially a wide plate with two prongs.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

The spiky green grass shown below is probably shallow sedge (Carex lurida) according to Drew Chaney, a.k.a., “Plant Man Drew.”

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

Field Observations

All of the photos in the preceding gallery show male No. 2 perched on vegetation overhanging a small stream, enabling him to both hunt/feed and wait for an opportunity to mate with a female.

Natural History: Males perch on sunlit vegetation overhanging stream or on flat rocks in shade at head of riffle, fly up into trees when disturbed. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6102-6103). Princeton University Press. Kindle Edition.

In my experience, Sable Clubtails — both male and female — also perch on ground cover vegetation in sunny clearings near small streams. For example, see my recent blog post featuring male No. 1.

Sable does in fact fly up into trees when their “flight” response is triggered by overzealous photographers; they have been observed perched in trees as high as 20 feet above the ground. Be patient — usually they return to the ground soon afterward.

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

Sable Clubtail dragonfly (male, No. 1)

June 26, 2020

After a two-year hiatus since I spotted my first Sable Clubtail dragonfly (Stenogomphurus rogersi) during June 2018, it was a pleasure see an old friend again!

The first photo is the “record shot” for this individual, that is, “get a shot, any shot.” It is literally the first shot I took as soon as I spotted the Sable male. As you can see, he was looking in my direction so I was unable to sneak up on him. That proved to be problematic.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

I tried to move slowly into position for a lateral view of the dragonfly.

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

The last photo is almost as far as I moved before Mr. Sable flew away — five shots and it was game over, man!

13 JUN 2020 | Fairfax County, VA | Sable Clubtail (male)

Later the same day I  was fortunate to photograph a more cooperative male that will be featured in a follow-up post.

Rare to Uncommon

Sable Clubtail has a limited range and is classified as a rare to uncommon species of odonate. The following map shows all official records for Sable Clubtail in the United States of America.

DSA Distribution Viewer | Sable Clubtail

Source Credit: Abbott, J.C. 2006-2018. OdonataCentral: An online resource for the distribution and identification of Odonata. Available at http://www.odonatacentral.org. (Accessed: June 11, 2018).

Key: blue dots = Dot Map Project; green dots = Accepted records; yellow dots = Pending records.

As you would expect, there are few official records for the Commonwealth of Virginia, and fewer records for Northern Virginia.

The Backstory

A short segment of a small stream that flows through a park in Northern Virginia seems to provide ideal habitat for Sable. By the end of Summer 2018, the stream had been degraded significantly by siltation as a result of runoff from dirt that was dumped uphill from the stream.

The following year, the stream channel was almost completely choked by vegetation that I assume flourished in the nutrient-rich sediment that had flowed into the stream. Net result: One and only one Sable Clubtail dragonfly was observed by several spotters who visited the stream site during 2019.

That’s the bad news. The good news is I saw at least three Sable Clubtails when I visited the stream site on Saturday, 13 June 2020. That’s not as many individuals as I saw in 2018, but the species seems to have rebounded a little from the damage done to its habitat.

As Jeff Goldblum said in Jurassic Park, “Life finds a way.” Let’s hope!

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

Another seep deep in the forest

July 24, 2019

“Two-board Bridge” is located along a marked trail in the forest at an undisclosed location in Prince William County, Virginia USA. The small, wooden footbridge crosses a large seep. The plant with broad green leaves is skunk cabbage (Symplocarpus foetidus).

04 JUN 2019 | PNC. William County, VA | “Two-board Bridge”

Location, location, location.

Seepage areas in the forest are prime locations for hunting habitat-specific odonates such as petaltails and some species of spiketails.

The Backstory

DSA members Ken Larsen and Michael Ready saw and photographed a single male Sable Clubtail (S. rogersi) on 01 June 2010 in Prince William County. Nine years later, neither Ken nor Michael were able to recall the exact location of their sighting, but they were able to point me toward the general vicinity where I might “rediscover” one of the descendants of the Sable they’d seen.

I asked Mike Powell to help me hunt for Sable. Mike did some solo exploration before we visited the site together. He mentioned there is a LOT of skunk cabbage along one of the trails he had followed. As soon as I saw the place, Mike will tell you I said “We should find Gray Petaltail here.” Not long afterward, we spotted the first of many T. thoreyi!

Coming full circle, Mike spotted a single male Sable Clubtail dragonfly about a week later in the same “neighborhood.” We searched the location intensively several more times but never saw another Sable.

Although Sable doesn’t live in seeps, our search for the right habitat for Sable led us to several seeps that are tributaries of the small creek where S. rogersi does live.

Gear Talk

Notice the disjointed human legs at the top of the image — they belong to Mike Powell, my good friend and photowalking buddy. Sometimes I get so focused on the subject of interest that I don’t see the bigger picture. I could say I included Mike’s legs in order to provide a sense of scale, but the truth is it’s an unintended consequence of poor photo composition.

Also gotta love the blown highlights in the photo! The high dynamic range between the shadows of the forest canopy and direct sunlight would have been better photographed as an HDR composite image.

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

New Life List additions in 2018 (odonates)

December 28, 2018

The anticipation of the hunt and the thrill of discovery — the adrenalin rush from finding the target species is ever more elusive as one gains experience and expertise. Accordingly, the number of additions to my Life List is fewer year after year.

Editor’s Note: List items are presented in chronological order, based upon the date of the spotting.

Twin-spotted Spiketail

A Twin-spotted Spiketail dragonfly (Cordulegaster maculata) was spotted at an undisclosed location in Fairfax County, Virginia USA. This individual is a male.

07 MAY 2018 | Fairfax County, VA | Twin-spotted Spiketail (male)

Brown Spiketail (male)

A Brown Spiketail dragonfly (Cordulegaster bilineata) was spotted at an undisclosed location in Fairfax County, Virginia USA. I saw a female Brown Spiketail on 09 May 2013. This individual is one of several males that I spotted on 07 and 11 May 2018.

11 MAY 2018 | Fairfax County, VA | Brown Spiketail (male)

Gray Petaltail

Gray Petaltail dragonfly (Tachopteryx thoreyi) was spotted at a forest seep. This individual is a male with a malformed abdomen that I nicknamed “Bender.”

06 JUN 2018 | Northern Virginia | Gray Petaltail (male)

Sable Clubtail

Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted perched near a small stream located in Fairfax County, Virginia USA. This individual is a male.

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Citrine Forktail damselfly (male)

Citrine Forktail damselfly (Ischnura hastata) was spotted during a stream-walk along South Fork Quantico Creek in Prince William Forest Park (PWFP), Prince William County, Virginia USA. This individual is a male.


Next post: Recognition in 2018.

Copyright © 2018 Walter Sanford. All rights reserved.

Powell’s Place

November 2, 2018

A single Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted perched alongside a small stream located in Fairfax County, Virginia USA.

I nicknamed a segment of the stream “Powell’s Place” in honor of Mike Powell, my good friend and photowalking buddy, who spotted the first Sable observed at this part of the stream. “Powell’s Place” is located downstream from Hotspot No. 1, where the stream re-emerges from an underground concrete pipe.

This individual is a male, as indicated by his indented hind wings and terminal appendages. Some dragonflies tend to be creatures of habit, returning to the same spot day-after-day. Perhaps this is the same individual spotted by Mike. Who knows?

I like the juxtaposition of complementary colors in the first photo.

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

The next photo shows the dragonfly perched deep within a shaded hidey-hole.

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

The last photo is a contender for my Odonart© Portfolio.

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Full disclosure: Adobe Photoshop was used to removed a tiny distracting element from the bottom-right half of the preceding image (the point of a single blade of grass).

Copyright © 2018 Walter Sanford. All rights reserved.

Beetlejuice

October 31, 2018

Look closely at the following photograph and ask yourself “What’s wrong with this picture?”

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Did you notice the dragonfly’s head is turned upside-down? That reminds me of the movie Beetlejuice (1988). Happy Halloween!

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

All three photos show the same Sable Clubtail dragonfly (Stenogomphurus rogersi), perched alongside a small stream located in Fairfax County, Virginia USA. This individual is a male, as indicated by his indented hind wings and terminal appendages. Notice his head is upside-up in the last two photos.

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Related Resource: Cobra Clubtail head-tilts, featuring a female with her head positioned nearly upside-down. I guess the upside-down head thing is characteristic of some members of Family Gomphidae (Clubtails).

Copyright © 2018 Walter Sanford. All rights reserved.

Hotspot No. 2

October 29, 2018

The Backstory

A small population of Sable Clubtail dragonflies (Stenogomphurus rogersi) was observed along three segments of a tiny stream located in Fairfax County, Virginia USA. I named the segments Hotspot No. 1, Hotspot No. 2, and “Powell’s Place.”

Hotspot No. 1 is the place where I saw my first Sable Clubtail. At least five individuals, all males, were observed by the author at this location. To date, almost all of the photos of Sable that have been published in this blog were taken at Hotspot No. 1.

Hotspot No. 2 is located upstream from Hotspot No. 1, near one of several seeps that feed the creek. This is the location where a female Sable Clubtail was spotted on 05 July 2018. As it turn out, that female was the last Sable spotted during 2018.

Powell’s Place” is located downstream from Hotspot No. 1, where the stream re-emerges from an underground concrete pipe. “Powell’s Place” is named for Mike Powell, my good friend and photowalking buddy, who spotted the first Sable observed at this segment of the stream. A related blog post will be published on Friday, 02 November 2018.

Hotspot No. 2

One or more male Sable Clubtail dragonflies were observed and photographed on 12 June 2018 at this location.

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Copyright © 2018 Walter Sanford. All rights reserved.

Field marks for identification of S. rogersi

October 22, 2018

The following annotated images illustrate field marks that can be used for identification of Sable Clubtail dragonfly (Stenogomphurus rogersi). Although there is some redundancy among the images, repetition is a good strategy for learning.

Male

Male Sable Clubtails have eyes that are green to turquoise in color, with a black occiput located between the eyes. They have a thin, black abdomen that flares to a small club featuring thin yellow flanges on abdominal segments seven through nine (S7-9).

The abdomen is marked with small pale dorsal triangles (S3-7) and tiny pale lateral spots. The number of dorsal triangles can vary individually and/or geographically, ranging from S3-5 to S3-7.

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Dennis Paulson, originator of the classification system for thoracic stripes in the Family Gomphidae (Clubtails), describes T1-4 as follows.

T1–2 broad and complete, touching at ends and often with stripe between them restricted and topped with spot; T3–4 fine, T3 incomplete. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6089-6093). Princeton University Press. Kindle Edition.

Note: T1-4 refers to the dark areas located on the sides of the thorax, not the lighter colored lines and spots. Due to space limitations, thoracic stripes are labeled using a numeral only (e.g., “1”) rather than a letter and numeral (e.g., “T1”).

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Their face is pale, marked with variable black crosslines (as shown in the inset photo, below).

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Male Sable Clubtails, like all male dragonflies, have three terminal appendages, collectively called “claspers.” All male clubtail dragonflies have indented hind wings.

Female

Female Sable Clubtails have a noticeably thicker abdomen than males. The occiput is a pale color, rather than black. Dorsal triangles, located on abdominal segments three through seven (S3-7), are much larger than those found on males. The lateral spots are somewhat larger as well.

05 JUL 2018 | Fairfax County, VA | Sable Clubtail (female)

Female Sable Clubtails, like all female dragonflies, have a pair of cerci (superior appendages) that have little or no function. All female clubtail dragonflies have rounded hind wings.

Related Resource: Stenogomphurus rogersi exuvia.

Copyright © 2018 Walter Sanford. All rights reserved.


%d bloggers like this: