Posts Tagged ‘Ashy Clubtail dragonfly’

Do-over

October 24, 2018

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

A focus-stacked composite image was created from 39 photos focused on the face and head of the exuvia. I had relatively little experience using Adobe Photoshop to make focus stacks when I created the first iterations of the Ashy Clubtail composite image. I was never satisfied completely with the final output, so I decided to do a do-over.

After…

The updated version of the composite image was created using my “Latest focus stacking workflow.”

Before…

The version that I published in late-March 2018 was created using the RAW photos (CR2) from my Canon digital camera, without any post-processing. I tried to adjust the white balance and color palette of the resulting composite image, but was unable to get the “look” I wanted. The image is probably over-sharpened too.

Which version do you prefer?

I know the version I like more. Which do you prefer, After or Before?

Tech Tips

The preceding images are composites of 39 photos taken using the following equipment: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for 3x magnification); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode.

Adobe Photoshop CC 2017 was used to focus stack the photos and post-process the final output.

According to the “Focus Stacking Step Size Calculator” embedded in the “Focus Stacking” Web page, the “safe step size” is 0.213 mm for an aperture of f/11 at 3x magnification using a full-frame DSLR. That’s right, 0.213 mm! The safe step size is the incremental distance at which the in-focus areas of two photos overlap. The ruler on the inexpensive focus rail that I use is marked in millimeters only, so I attempted to move the focus rail in tiny increments in two passes: one pass moving from front-to-back; and a second pass from back-to-front.

Copyright © 2018 Walter Sanford. All rights reserved.

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Post update: Phanogomphus lividus exuvia

April 13, 2018

Phanogomphus lividus exuvia, my identification guide for Ashy Clubtail exuviae, was updated to feature two new annotated high-magnification macro composite images.

  • Photo No. 1: The specimen was rehydrated/relaxed in order to reposition the front legs for an unobstructed view of the prementum, especially the median lobe of the labium.
  • Photo No. 2: A close-up view of the anal pyramid (terminal appendages) verified the “superior caudal appendage (epiproct) is as long as inferiors (paraprocts).”

The first image is a composite of six photos that shows a ventral view of the prementum.

Editor’s Note: Sincere thanks to Sue and John Gregoire for guiding me to the location of the median lobe.

The last image is a composite of 15 photos that shows a dorsal view of the abdomen; the inset image is a selection from a composite of 10 photos that shows a ventral view of the anal pyramid.

No. 2 | Ashy Clubtail (Phanogomphus lividus) | exuvia (anal pyramid)

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

Tech Tips

The following equipment was used to shoot all of the photos for the preceding composite images: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for f/8 at either 2x or ~3x magnification); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image by “round-tripping” with Apple Aperture.

Copyright © 2018 Walter Sanford. All rights reserved.

P. lividus prementum

April 11, 2018

The following image shows a composite of six photos of the prementum for an Ashy Clubtail dragonfly (Phanogomphus lividus) exuvia. The composite is one of at least two new images that will be annotated and used to update Phanogomphus lividus exuvia, my identification guide for Ashy Clubtail exuviae.

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

Tech Tips

The following equipment was used to shoot all of the photos for the preceding composite image: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for f/8 at ~3x magnification); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image by “round-tripping” with Apple Aperture.

Copyright © 2018 Walter Sanford. All rights reserved.

Phanogomphus lividus exuvia

April 5, 2018

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

A two-step process was used to verify the identity of the exuvia.

  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), as shown in Photo No. 1 and 3.
  • Antennae are club-like (not thin and thread-like, as in  Aeshnidae larvae), as shown in Photo No. 1.

It’s simple and straightforward to recognize this specimen is a clubtail.

No. 1 | Ashy Clubtail (Phanogomphus lividus) | exuvia (face-head)

Step 2. Genus and species

Lateral spines are present on abdominal segments six through nine (S6-S9).

The superior caudal appendage (epiproct) is as long as inferiors (paraprocts), as shown in Photo No. 4. The view of the terminal appendages is still slightly obscured by debris after the specimen was cleaned, making it challenging to distinguish the cerci from the paraprocts. Nonetheless, the epiproct and paraprocts appear to be nearly the same length.

The median lobe of the labium (prementum) is straight-edged, as shown in Photo No. 5.

After emergence

The next photograph shows the Ashy Clubtail dragonfly after emergence from one of Bob Perkins‘ holding tanks. Phanogomphus lividus is 48-56 mm in total length (Paulson, 2011).

Image used with permission from Bob Perkins.

This individual is a female, as indicated by its rounded hind wings and terminal appendages.

Image used with permission from Bob Perkins.

Related Resource

The dichotomous key for Gomphus (now Phanogomphus) that appears on p. 20 in Identification Keys to Northeastern Anisoptera Larvae, compiled by Ken Soltesz, was used to attempt to verify the genus and species of the exuvia. Markers that match this specimen are highlighted in boldface green text. Three boldface green asterisks (***) are used to highlight the thread for identification of P. lividus. Disclaimers are highlighted in boldface red text.

1a. Lateral spines on abdominal segments 7 to 9 (very minute if present on 6). [2]
***1b. Lateral spines on abdominal segments 6 to 9 well developed. [3]

3a. Superior caudal appendage (epiproct) shorter than inferiors (paraprocts); Teeth on lateral lobes of labium obsolete or poorly developed. [quadricolor]
***3b. Superior caudal appendage (epiproct) as long as inferiors (paraprocts); Teeth on lateral lobes of labium well developed. [4]

***4a. Median lobe of labium straight-edged. [lividus]
4b. Median lobe of labium convex-edged. [5]


Note: The weakest aspect of this key is couplet 4, as it applies to Gomphus descriptus [Harpoon Clubtail], the difference in the “convexity” of the median lobe between lividus and descriptus being very slight and difficult to discern in practice. Donnelly (pers. comm.) has found that, at least with New York specimens, the posterior narrowing of the median lobe of the labium is more abrupt in livid, and relatively gradual in descriptus. Also, the labial teeth are better developed in livid than in descriptus. These characters are so relative that any unknown suspected of being either of these species should be compared to reference specimens.

Tech Tips

The following equipment was used to shoot Photo No. 2 and 3: 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); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode. Photo No. 1, 4, and 5Canon MP-E 65mm Macro lens (manual focus only, set for either 2x or 3x magnification) plus the multiple-flash setup.

Photo No. 1-3 are focus-stacked composite images created and annotated using Adobe Photoshop CC 2017.

Bob Perkins’ photos were shot using a Canon EOS Rebel T3i camera body and Canon EF-S 60mm macro lens.

Copyright © 2018 Walter Sanford. All rights reserved.

Refinements in focus stacking workflow

April 3, 2018

By trial and error, I’m slowly refining the workflow that I use to create focus-stacked composite images. My goal is maximizing efficiency while minimizing unexpected results. I’m planning to publish a step-by-step “how to” tutorial after my workflow is honed to perfection. Hah! I’m not sure that’s attainable, but I’m working on it.

In the meantime, here are two more composite images created using the latest refinements in my focus stacking workflow.

Both composite images were created from three photos: one focused on the head/prementum; another focused on the middorsal body; and the last focused on the anal pyramid (terminal appendages).

I started using the High Pass filter in Photoshop to sharpen images and I am pleased with the results.

Sharpening doesn’t fix out-of-focus areas, such as the far hind leg in both images. I’m not sure what the “sweet spot” is for the Canon 100mm macro lens; the consensus seems to be photos are sharpest at f/8. I shoot at f/22 for single images with one focus point. I have been testing f/18 for the two- and three-photo focus stacks published recently, but as you can see, I should probably add a fourth photo focused on the farthest part of the subject.

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuviafrom the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

Tech Tips

The following equipment was used to shoot all three photos in the composite image: 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); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite images by “round-tripping” with Apple Aperture. Although the round-trip has a few detours in my experimental workflow, there are fewer unpleasant surprises along the way. Worth the extra steps, in my opinion.

Copyright © 2018 Walter Sanford. All rights reserved.

Ashy Clubtail dorsal view composite

April 1, 2018

One look at the unusual filename of the following image, and you know it’s a composite of three photos: one focused on the head; another focused on the middorsal body; and the last focused on the anal pyramid (terminal appendages).

The results appear to be worth the extra time and effort to create a high-quality image of a beautiful specimen.

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuviafrom the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

Tech Tips

The following equipment was used to shoot all three photos in the composite image: 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); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image by “round-tripping” with Apple Aperture.

Copyright © 2018 Walter Sanford. All rights reserved.

Ashy Clubtail exuvia focus stack

March 30, 2018

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividus) nymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

Tech Tips

The preceding image is a composite of 39 photos taken using the following equipment: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for 3x magnification); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode.

Adobe Photoshop CC 2017 was used to focus stack the photos and post-process the final output.

According to the “Focus Stacking Step Size Calculator” embedded in the “Focus Stacking” Web page, the “safe step size” is 0.213 mm for an aperture of f/11 at 3x magnification using a full-frame DSLR. That’s right, 0.213 mm! The safe step size is the incremental distance at which the in-focus areas of two photos overlap. The ruler on the inexpensive focus rail that I use is marked in millimeters only, so I attempted to move the focus rail in tiny increments in two passes: one pass moving from front-to-back; and a second pass from back-to-front.

Copyright © 2018 Walter Sanford. All rights reserved.

Ashy Clubtail dragonfly (male)

May 20, 2017

An Ashy Clubtail (Phanogomphus lividus) was spotted during a photowalk along a mid-size stream in Fairfax County, Virginia USA.

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

This individual is a male, as indicated by his terminal appendages and indented hind wings.

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

The last photo is uncropped. The wider view shows the Ashy Clubtail is well-camouflaged when perching on the ground.

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

The Backstory

I visited a new location in Fairfax County, Virginia on 03 May 2017, following my hunch that the spot might be a good place to find some of the more uncommon species of odonates. Turns out my hunch was right!

I saw species from four families of dragonflies: male Stream Cruiser dragonfly (Didymops transversa); male Springtime Darner dragonfly (Basiaeschna janata); female and male Common Baskettail dragonfly (Epitheca cynosura); female and male Spine-crowned Clubtail dragonfly (Hylogomphus abbreviatus); at least two male Lancet Clubtail dragonflies (Phanogomphus exilis); and the male Ashy Clubtail (Phanogomphus lividus) featured in this post.

In addition, I saw lots of teneral damselflies from the Family Coenagrionidae (Pond Damsels), possibly Blue-tipped Dancer (Argia tibialis).

03 MAY 2017 | Fairfax County, VA | teneral damselfly

Copyright © 2017 Walter Sanford. All rights reserved.

Lancet Clubtail dragonflies (males)

May 14, 2017

At least two Lancet Clubtail dragonflies (Phanogomphus exilis) were spotted during a photowalk along a mid-size stream in Fairfax County, Virginia USA.

03 MAY 2017 | Fairfax County, VA | Lancet Clubtail (male)

These individuals are males, as indicated by their terminal appendages and indented hind wings.

03 MAY 2017 | Fairfax County, VA | Lancet Clubtail (male)

The next photograph was taken at a later time than the first two photos. All of the photos in this post were taken near the same location. Is this another male, or the same one featured in the preceding photos? Who knows?

03 MAY 2017 | Fairfax County, VA | Lancet Clubtail (male)

Lancet Clubtail versus Ashy Clubtail

Lancet Clubtail looks similar to Ashy Clubtail (Phanogomphus lividus). The only way to differentiate the two species with certainty is to examine their external reproductive anatomy; this is impossible unless the specimens are captured and examined in-hand.

Relative size is used sometimes to identify the two species: Lancet Clubtail is slightly smaller than Ashy Clubtail. There are two problems with this method of identification. First, it is virtually impossible to determine the exact size of a specimen in the field unless it is captured and measured. Second, some natural variation in size should be expected among individuals of the same species.

A quick-and-dirty method for differentiating Lancet- and Ashy Clubtails with some degree of certainty is to look at the markings on abdominal segments eight and nine (S8-9). Lancet Clubtail has a “spearpoint” on top of abdominal segment eight (S8) that almost reaches the end of the segment, a wide yellow stripe on top of segment nine (S9), and irregular yellow markings on the sides of segments eight and nine (S8-9).

03 MAY 2017 | Fairfax County, VA | Lancet Clubtail (male)

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

In contrast, Ashy Clubtail has a spearpoint on top of abdominal segment eight (S8) that is less than half the length of the segment, segment nine (S9) may or may not have a pale yellow stripe on top, and the sides of segments eight and nine (S8-9) may or may not have “poorly defined” yellow markings.

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

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

Coloration is variable among individuals of the same species, so looking at abdominal markings isn’t always a reliable method of identification. In this case, it works beautifully.

Editor’s Note: The word “spearpoint” and the phrase “poorly defined” are descriptors attributed to Dennis Paulson, Dragonflies and Damselflies of the East (Princeton Field Guides). Princeton University Press. Kindle Edition.

Copyright © 2017 Walter Sanford. All rights reserved.

Ashy Clubtail dragonfly (male)

April 28, 2017

An Ashy Clubtail dragonfly (Phanogomphus lividus) was spotted during a photowalk at Riverbend Park, Fairfax County, Virginia USA. This individual is a male, as indicated by his indented hind wings and terminal appendages.

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”).

Notice the epiproct is a large “plate” that spans both cerci, as shown in the full-size version of the following photo.

One thing you can count on when photographing Ashy Clubtails (well, usually) is the subject will be perching on a chaotic background that is difficult to crop without creating leading lines that mislead the viewer’s eye and distracting elements near the edges of the image.

Copyright © 2017 Walter Sanford. All rights reserved.


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