Posts Tagged ‘Family Corduliidae (Emeralds)’

Non-stop flight

April 22, 2017

On 18 April 2017, a Common Baskettail dragonfly (Epitheca cynosura) was spotted patrolling part of the shoreline at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, in flight.

108mm (600mm equivalent) | ISO 100 | f/5.2 | 1/800s | -1 ev | flash fired

The photograph was taken using a Panasonic LUMIX DMC-FZ150 superzoom bridge camera and a Canon 580EX Speedlite external flash set for manual mode at 1/8 power and 105mm zoom.

Related Resource: Stop-action photography of dragonflies in flight, a blog post by Walter Sanford, features Phil Wherry’s answer to my question “How fast would the camera shutter speed need to be in order to freeze all motion of a dragonfly in flight?”

Copyright © 2017 Walter Sanford. All rights reserved.

Late-stage emergent baskettail dragonfly

April 18, 2017

Common Baskettail dragonfly (Epitheca cynosura) was spotted at Painted Turtle Pond during a photowalk around Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA. This individual is a late-stage emergent teneral female.

I photographed the process of emergence from the first sighting to the time when the teneral dragonfly flew away: I shot 23 photos in approximately 16 minutes; time is compressed by showcasing six (6) select photos taken at major milestones during the event.

The following photo is the first image from a time-series documenting the emergence of the teneral female. Elapsed time is expressed in hh:mm:ss format, e.g., 00:00:00 is the time when I spotted the emergent teneral female, and 00:16:08 is the total elapsed time.

13 APR 2016 | 11:38:41 am EDT | Elapsed time: 00:00:00

Notice the drop of fluid at the tip of the abdomen. Emerging dragonflies pump fluid into their wings, causing the wings to expand. Next, the same fluid is withdrawn from the wings and used to expand the abdomen. Excess fluid is expelled afterward.

13 APR 2016 | 11:40:48 am EDT | Elapsed time: 00:02:07

The next photo shows the first time the wings opened.

13 APR 2016 | 11:48:55 am EDT | Elapsed time: 00:10:14

Then the wings closed again and remained closed for a while.

13 APR 2016 | 11:51:02 am EDT | Elapsed time: 00:12:21

The wings reopened a few minutes later. Notice that several wings are malformed slightly.

13 APR 2016 | 11:54:14 am EDT | Elapsed time: 00:15:33

Finally, the wings open up, and very soon the teneral adult flies away. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 468). Princeton University Press. Kindle Edition.

The teneral female dragonfly flew away immediately after the last photo in the time-series.

13 APR 2016 | 11:54:46 am EDT | Elapsed time: 00:16:08

This individual is a female, as indicated by her cerci (superior appendages) and thick abdomen. Common Baskettail females have shorter cerci and a thicker abdomen than males of the same species.

Exuviae (in situ)

Several dragonfly exuviae were spotted at Painted Turtle Pond; it’s possible they are cast skins from Common Baskettail. More later after the exuviae are identified using a dichotomous key for dragonfly larvae.

13 APR 2017 | OBNWR | Common Baskettail (exuvia)

These exuviae are not the one from which the teneral female featured in this post emerged.

13 APR 2017 | OBNWR | Common Baskettail (exuvia)

Copyright © 2017 Walter Sanford. All rights reserved.

Common Baskettail dragonfly (male)

April 16, 2017

A Common Baskettail dragonfly (Epitheca cynosura) was spotted near Painted Turtle Pond during a photowalk at Occoquan Bay National Wildlife Refuge (OBNWR). Common Baskettail is a member of Family Corduliidae (Emeralds); this species is seen during early spring in mid-Atlantic United States like Virginia.

I thought this might be a Slender Baskettail dragonfly (Epitheca costalis) due to narrowing of its abdomen. Turns out that was wishful thinking.

13 APR 2017 | OBNWR | Common Baskettail (male)

This individual is a male, as indicated by his terminal appendages. The curved shape of the cerci (superior appendages) is a key field marker for Common Baskettail; in contrast, the cerci for Slender Baskettail tend to be more parallel. Thanks to Mike Boatwright and Paul Guris, members of the Northeast Odonata Facebook group, for reminding me of this pearl of wisdom!

I think baskettail cerci look “rubberized,” like the handles of metal tools made for working with electricity. Whenever I see this distinctive field marker, shown clearly in the following photos, I know the dragonfly is probably a species of baskettail.

13 APR 2017 | OBNWR | Common Baskettail (male)

The last photo shows a dorso-lateral view of the male dragonfly. Notice the epiproct (inferior appendage) is visible clearly in this photo.

13 APR 2017 | OBNWR | Common Baskettail (male)

Also notice the light-colored spots on the hairs covering the body of the dragonfly. The following article by John Abbott suggests the spots may be some type of pollen.

Related Resource: Identification of Male Epitheca (Tetragoneuria) in Texas, by John C. Abbott.

Copyright © 2017 Walter Sanford. All rights reserved.

Epitheca princeps exuvia

March 5, 2017

The following Prince Baskettail dragonfly (Epitheca princeps) exuvia, on temporary loan from a friend, had been identified before I borrowed the specimen. A two-step process was used to verify the genus and species 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 Corduliidae (Emeralds).

  • The specimen has a mask-like labium that covers the face, characteristic of four families: Cordulegastridae (Spiketails); Corduliidae (Emeralds); Libellulidae (Skimmers); and Macromiidae (Cruisers).
  • There is no horn on top of the face-head, characteristic of Macromiidae, so it’s not a cruiser.
  • Cordulegastridae has jagged crenulations on its labium, so it’s not a spiketail. The crenulations for Corduliidae and Libellulidae look similar.
  • Look at the anal pyramid to differentiate Corduliidae and Libellulidae [See Photo No. 4.]: It’s probably Corduliidae if the cerci are at least half as long as the paraprocts. [Editor’s Note: It’s probably Libellulidae if the cerci are less than half the length of the paraprocts.]

In summary, the exuvia has a mask-like labium with relatively smooth crenulations, no horn on its face-head, and the cerci are more than half as long as the paraprocts, confirming that the specimen is a member of Family Corduliidae (Emeralds).

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 1 | Prince Baskettail (Epitheca princeps) | exuvia (face-head)

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

Step 2. Genus and species

Characters from two dichotomous keys were used to identify the genus and species for the exuvia. Although palpal/mental setae were not examined, all other characters match Epitheca princeps.

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

Dichotomous Key 1

Identification Keys to Northeastern Anisoptera Larvae, compiled by Ken Soltesz.

Key to the Families of Anisoptera, page 5.

Key to the Genera of the Family Corduliidae, page 28.

Dichotomous Key 2

Corduliidae Selys – EmeraldsOdonata Nymphs of Michigan, by Ethan Bright and Mark F. O’Brien, UMMZ-Insect Division.

Epitheca Burmeister, 1839 (Corduliidae) – Baskettails

  • 1a. Distal half of dorsal surface of prementum heavily setose; palpal setae usually 4, rarely 5(Fig. 2) – Subgenus Epicordulia, E. princeps

More annotated images

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 2 | Prince Baskettail (Epitheca princeps) | exuvia (dorsal)

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

Mid-dorsal hooks present, well-developed on some abdominal segments.”

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 3 | Prince Baskettail (Epitheca princeps) | exuvia (dorso-lateral)

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

“With lateral spines on Ab8 [S8].” “Lateral spines on Ab9 [S9] at least 2.0x as long as those on Ab8 [S8], at least equal to mid-dorsal length of Ab9 [S9].” The cerci are at least half as long as the paraprocts.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 4 | Prince Baskettail (Epitheca princeps) | exuvia (anal pyramid)

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

Photo No. 5 shows a wider view of the ventral side of the specimen.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 5 | Prince Baskettail (Epitheca princeps) | exuvia (ventral)

Photo No. 6 shows a zoomed-in view of the prementum.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 6 | Prince Baskettail (Epitheca princeps) | exuvia (prementum)

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

Photo No. 7 shows another view of the prementum.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 7 | Prince Baskettail (Epitheca princeps) | exuvia (prementum)

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 and a Raynox DCR-250 close-up filter; Canon 580EX II external flash, off-camera, in manual mode; Canon 580EX external flash, off-camera, in manual mode; and a Yongnuo YN-622C-TX E-TTL II Wireless Flash Controller for Canon plus a two-pack of Yongnuo YN-622C II E-TTL Wireless Flash Transceivers for Canon.

A Canon Extender EF 1.4x II was used for more magnification in Photo No. 4, 6, 7 and 9. Adding the tele-extender results in a 1 f/stop loss of light; additional backlight was added to the scene using a Nissin i40 external flash unit (off-camera, in SF mode).

Adobe Photoshop CC 2017 was used to annotate selected images.

Photo No. 8 and 9 show early work to get a good shot of the face-head, before Photo No. 1 emerged as the clear winner. I prefer Photo No. 1 because it provides the best view of the face-head, has the best composition and exposure, plus I like the way the exuvia seems to be floating in mid-air.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 8 | Prince Baskettail (Epitheca princeps) | exuvia (face-head)

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

No. 9 | Prince Baskettail (Epitheca princeps) | exuvia (face-head)

Although I have never seen a perching adult Prince Baskettail dragonfly, I was fortunate to shoot the following photo of a male in flight, featured in the blog post Changing of the guard.

A Prince Baskettail dragonfly (Epitheca princeps) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, shown in flight.

No. 10 | 14 JUN 2016 | JMAWR | Prince Baskettail (male, in flight)

Related Resources:

Copyright © 2017 Walter Sanford. All rights reserved.

Buddha

March 3, 2017

I found Buddha, in this case, the version known as “Happy Buddha.” (Notice the exuvia seems to be smiling.) I think I’ll rub Buddha’s belly to see whether it brings me good luck, prosperity and wealth.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

Prince Baskettail dragonfly (Epitheca princeps) exuvia (ventral)

But seriously folks, this is a photo of a Prince Baskettail dragonfly (Epitheca princeps) exuvia on temporary loan. The date and location where the specimen was collected is unknown. More photos of this exuvia (including several annotated images) will be published in an upcoming post.

The following photo is the original. The preceding photo was cropped and rotated clockwise 90-degrees.

A Prince Baskettail dragonfly (Epitheca princeps) exuvia collected from an unknown location. This specimen is on temporary loan from Huntley Meadows Park, Fairfax County, Virginia USA.

Prince Baskettail dragonfly (Epitheca princeps) exuvia (ventral)

Copyright © 2017 Walter Sanford. All rights reserved.


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