Posts Tagged ‘Eastern Ringtail dragonfly’

Eastern Ringtail reunion, continued

August 5, 2019

Whenever possible I prefer to photograph odonates against a clean background, such as the concrete pavement in my last blog post. In my opinion, a simpler background makes it easier for the viewer to focus on the subject.

In contrast, my photowalking buddy Mike Powell prefers a “natural” background (as opposed to man-made). Knowing Mike’s preference, I “influenced” an Eastern Ringtail (Erpetogomphus designatus) to relocate from his perch on a concrete sidewalk to a new perch on a grass lawn. Although the green grass complements the unusual color palette of the dragonfly, the viewer’s eye must work harder to find the subject.

This individual is a male, as indicated by his “indented” hind wings, and terminal appendages. He is perched on a grassy area in between concrete sidewalks surrounding a berm/observation area alongside the boat ramp, near the main parking lot at Riverbend Park.

Adult flight period

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for E. designatus is from May 16 to September 24. The species is classified as uncommon to common. Its habitat is “rivers.”

Bear in mind, Dr. Roble’s records are for the entire state, therefore the adult flight period for E. designatus seems to be longer than it is in reality. The adult flight period for a single site is probably shorter. For example, according to records for Northern Virginia maintained by Kevin Munroe, former manager of Huntley Meadows Park, the adult flight period for Eastern Ringtail is 09 June to 20 September.

Related Resource: Posts tagged ‘Eastern Ringtail dragonfly’

Copyright © 2019 Walter Sanford. All rights reserved.

Reconnecting with Eastern Ringtail

August 2, 2019

I used to be a science teacher at a public school where the building engineer had a great line for postponing and/or begging off maintenance work: “I’m only one man!” Well, when it comes to odonate hunting I have come to realize you can’t have it all — every year you need to make and prioritize a “target list” of species that you would really like to find/see and pass on many other old favorites.

For example, Eastern Ringtail (Erpetogomphus designatus). Although E. designatus is one of my favorite dragonflies, I had to pass on seeing them during 2018 in favor of hunting the elusive Tiger Spiketail (Cordulegaster erronea). It was good to reconnect with Eastern Ringtail recently during a brief photowalk with Michael Powell along the Potomac River at Riverbend Park in Fairfax County, Virginia USA.

The following photo set provides a brief example of what I call “working the shot.” The first photo is what some other ode hunters call the “record shot,” meaning get a shot, any shot of the subject in case it flies away and is never seen again.

Slowly I moved into position to get the shot I wanted, shown below.

This individual is a male, as indicated by his “indented” hind wings, and terminal appendages. He is perched on a concrete sidewalk around a berm/observation area alongside the boat ramp, near the main parking lot.

By this time in the ode hunting season, I was happy to be able to find the target species quickly and with almost no fear of pesty parasites such as chiggers, ticks, and mosquitos!

Related Resource: Posts Tagged ‘Eastern Ringtail dragonfly’

Copyright © 2019 Walter Sanford. All rights reserved.

Erpetogomphus designatus exuvia

February 28, 2018

Michael Powell collected several odonate exuviae during a photowalk along the Potomac River in Fairfax County, Virginia USA, including two damselflies and two dragonflies. The exact date is uncertain, although Mike thinks the exuviae were collected sometime between 19-23 July 2017.

A two-step process was used to identify the genus and species of one of the two dragonfly exuviae.

  1. Determine the family.
  2. Determine the genus and species.

Step 1. 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 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). [See Photo No. 4.]
  • Antennae are club-like (not thin and thread-like, as in Aeshnidae). [See Photo No. 1.]
  • Eyes not exceptionally large compared to the size of the head (not large, as in Aeshnidae). [See Photo No. 1.]
(See a full-size version of the original photo, without annotation.)

Step 2. Genus and species

The dichotomous key for Erpetogomphus larvae that appears on pp. 156-157 in Dragonflies of North America, Third Edition by Needham et al. was used to identify the genus and species of the exuvia. The first couplet [1, 1′] is as follows.

1. Dorsal hooks well-developed on abdominal segments 2-9 (Fig. 183a) [2]
1’. Dorsal hooks absent or vestigial on abdominal segments 7-9 (Fig. 183c) (usually present on at least some of the more anterior segments [3]

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

A leap of faith is required to see the small dorsal hooks present on abdominal segments two through nine (S2 – S9), but they are there.

Notice the divergent wing pads. The white filaments that extend from the split in the thorax (as shown above) are breathing tubes, artifacts of the unique respiratory system of dragonfly nymphs.

2(1). Lateral spines present on abdominal segments 6-9 only; femora with long, hair-like setae [designatus] [Eastern Ringtail]
2’. Lateral spines present on abdominal segments 5-9 only; femora without long, hair-like setae [constrictor] [Knob-tipped Ringtail]

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

The caudal appendages (terminal appendages) are all about the same length, a key marker for designatus.

Notice the flat labium that doesn’t cover the face, as shown in the following photo.

This specimen is tentatively identified as an exuvia from an Eastern Ringtail dragonfly (Erpetogomphus designatus). The exuvia that Mike Powell collected is similar in appearance to the following excellent photograph of an Erpetogomphus designatus nymph by Steve Krotzer, Haysop Hill Photography.

Image used with permission from Steve Krotzer.

Tech Tips

The following equipment was used to shoot Photo No. 2 and 4: 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 LitePhoto No. 1 and 3: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for 2x magnification); and Canon MT-26EX-RT Macro Twin Lite. A Sunpak LED-160 Video Light (with a white translucent plastic filter) was used for some photos.

Adobe Photoshop CC 2017 was used to annotate selected images.

Copyright © 2018 Walter Sanford. All rights reserved.

Adding a 16mm extension tube

August 2, 2017

Optics theory

The net effect of adding an extension tube between a lens and camera body is the “working distance” is decreased, that is, the distance from the front of the lens barrel to the subject is decreased. A smaller working distance means the same lens will focus closer to the subject, thereby increasing magnification.

The effect is greater at shorter focal lengths, as shown by the following table of magnification for the two extension tubes sold by Fujifilm USA.

Table courtesy Fujifilm USA.

Theory into practice

An Eastern Ringtail dragonfly (Erpetogomphus designatus) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female, as indicated by her terminal appendages and rounded hind wings.

Both photos in this set were taken using my Fujifilm X-T1 digital camera, Fujinon XF55-200mm zoom lens plus a “Fotasy” brand 16mm extension tube, and Fujifilm EF-X500 shoe mount flash. The lens was set for a focal length of 200mm (~300mm, 35mm equivalent).

At 200mm, the working distance of the lens is 905 mm (90.5 cm, ~35.63 in), or approximately three (3) feet. With a 16mm extension tube mounted between the lens and camera body, the working distance is reduced to 595 mm (59.5 cm, ~23.43 in), or approximately two (2) feet. At a focal length of 55mm, adding the extension tube would result in photos that look more like “macro” photos; at 200mm, adding the extension tube resulted in photos that look like a lens with a longer focal length was used to take the shots.

The first photo is uncropped. I’ve never been able to get a shot like this using a mid-range telephoto zoom lens such as the Fujinon 55-200mm. The 16mm extension tube is the difference-maker.

The last photo is cropped slightly, but not enough to affect the apparent magnification. I look closely at the edges of my photos. In this case, I cropped the photo to remove some distracting elements and leading lines.

Editor’s Notes

I bought a set of two “Fotasy” brand extension tubes (10mm, 16mm) years before Fujifilm released their set of two. The advantage of the Fotasy extension tubes is a set of two costs a little more than half as much as a single Fujifilm extension tube. The disadvantage is compatibility. The Fotasy extension tubes work with my Fujinon XF18-55mm (27-82.5mm, 35mm equivalent) “kit” lens and Fujinon XF55-200mm mid-range telephoto zoom lens; they don’t work with my Fujinon XF100-400mm (152-609mm, 35mm equivalent) telephoto zoom lens. For what it’s worth, the 100-400mm lens was released after the Fotasy extension tubes. Bottom line: I recommend Fujifilm extension tubes, despite the fact that they are significantly more expensive than Fotasy extension tubes.

The Depth of Field is razor thin, in contrast with shooting without an extension tube. I shot the preceding photos at f/11; f/16 or smaller would have been better.

In order to reduce “camera shake,” I almost always shoot in shutter priority mode using the reciprocal rule. Remember, it’s the 35mm equivalent that matters: since my lens is ~300mm, the shutter speed should be set for at least 1/300s; in this case, it was set for 1/1,000s. A monopod was used for added stability.

Copyright © 2017 Walter Sanford. All rights reserved.

Eastern Ringtail dragonfly (female)

July 21, 2017

An Eastern Ringtail dragonfly (Erpetogomphus designatus) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female, as indicated by her terminal appendages and rounded hind wings.

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

I saw tens of male Eastern Ringtail, but only one female.

The preceding photograph is my favorite in the set. I like the way the neutral colors in the pavement complement the coloration of the female.

Copyright © 2017 Walter Sanford. All rights reserved.

“Big Boy”

July 19, 2017

Several Eastern Ringtail dragonflies (Erpetogomphus designatus) were spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. These individuals are male, as indicated by their terminal appendages and “indented” hind wings.

All of the photos in this set were taken using my Fujifilm X-T1 digital camera, Fujinon 100-400mm telephoto zoom lens, and Fujifilm EF-X500 shoe mount flash.

I nicknamed the Fujinon 100-400mm lens “Big Boy” because it’s so big and heavy. I use a Sunpak 6700M monopod and Vanguard SBH 100 ball head to support the lens.

Zoom in on the full-size version of the preceding photo. Notice the terminal appendages are spread apart, revealing a clear look at both the cerci and hook-shaped epiproct.

Related Resource: You complete me – a blog post published on 19 February 2016 in which I shared my first impressions of the Fujinon 100-400mm telephoto zoom lens.

Copyright © 2017 Walter Sanford. All rights reserved.

Eastern Ringtail dragonflies (more males)

July 17, 2017

Many Eastern Ringtail dragonflies (Erpetogomphus designatus) were spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. All of the individuals in this gallery are male, as indicated by their terminal appendages and “indented” hind wings.

Please look at the full-size version of each photo in order to appreciate the coloration of these handsome male dragonflies.

Copyright © 2017 Walter Sanford. All rights reserved.

Eastern Ringtail dragonflies (males)

July 15, 2017

Tens of Eastern Ringtail dragonflies (Erpetogomphus designatus) were spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. Both individuals featured in this post are male, as indicated by their terminal appendages and “indented” hind wings.

Regular readers of my photoblog know I’m fond of head-tilts in which the dragonfly seems to display some of its personality, especially when the individual is looking at me. Like the male featured in the following photo — one of my all-time favorites!

In my opinion, the unique coloration of Erpetogomphus designatus rivals Genus Ophiogomphus (Snaketails). There, I said it!

Copyright © 2017 Walter Sanford. All rights reserved.

Everyone’s gotta eat!

August 27, 2016

Several Eastern Ringtail dragonflies (Erpetogomphus designatus) were spotted during photowalks along the Potomac River at Riverbend Park.

Eastern Ringtail seems to be a voracious predator, based upon an admittedly small sample size. Two individuals were observed eating smaller insects.

Male

The first individual is a male, as indicated by his terminal appendages; he is feeding upon an unknown black winged insect.

Female

The last individual is a female, as indicated by her terminal appendages; she is eating an unknown species of damselfly.

Almost gone, except for several legs!

Editor’s Note: The title of this post is an homage to Laura Lecce, a regular reader of my photoblog. Thanks for the inspirational comment on one of my previous posts, Laura!

Copyright © 2016 Walter Sanford. All rights reserved.

More Eastern Ringtail dragonflies

August 19, 2016

One female and two male Eastern Ringtail dragonflies (Erpetogomphus designatus) were spotted during a follow-up photowalk along the Potomac River at Riverbend Park.

Female and male Eastern Ringtail are somewhat similar in appearance. Terminal appendages, the shape of their hind wings, and the relative size of their club are good field markers to differentiate specimens by gender.

Female

The first individual is a female, as indicated by her terminal appendages. Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

An Eastern Ringtail dragonfly (Erpetogomphus designatus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (female)

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

The preceding dorsal view of the dragonfly shows its hind wings are rounded near the body, a good field marker for female clubtail dragonflies. In contrast, the hind wings of male clubtails are “indented.” Also notice the female “club” is slightly smaller than the male club, as shown in the following photos.

Male 1

The male’s abdomen is slightly thinner (shown below); the female’s abdomen is slightly thicker (shown above).

An Eastern Ringtail dragonfly (Erpetogomphus designatus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

Male 2

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”).

An Eastern Ringtail dragonfly (Erpetogomphus designatus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male, perching in the obelisk position.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

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

Notice the male’s hind wings are “indented” near the body, as shown in the last two photos.

An Eastern Ringtail dragonfly (Erpetogomphus designatus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

An Eastern Ringtail dragonfly (Erpetogomphus designatus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male.

08 AUG 2016 | Riverbend Park | Eastern Ringtail (male)

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

  • Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | female | top view
  • Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | female | side view
  • Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | male | top view
  • Genus Erpetogomphus | Erpetogomphus designatus | Eastern Ringtail | male | side view

Copyright © 2016 Walter Sanford. All rights reserved.


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