Posts Tagged ‘Family Corduliidae (Emeralds)’

Previews of Coming Attractions – Fall Species of Odonates

August 31, 2021

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summver); and Late Season (fall).

As we endure the “Dog Days of Summer,” waiting for the calendar to turn to fall, it’s time to begin looking for the Late Season (fall) species of odonates.

This blog post provides a photo sampler of some of the fall species of odonates that can be seen during September, October, and November in the Commonwealth of Virginia. This post is not intended to be a comprehensive field guide that features every odonate species that can be seen during the same time period.

Full Disclosure

Some fall species are easier to find than others. And some species are flyers rather than perchers, making it almost essential to capture them in flight using an insect net. That being said, it’s richly rewarding to find any of the rare to uncommon species so do your homework and be persistent. Good luck and happy hunting!


Editor’s Notes

Click on the date listed in the caption for each photo to see the original blog post for that image; click on the odonate name to see all of my blog posts related to that species.

Sincere thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for providing photographs of many of the rare to uncommon fall species of odonates featured in this photo sampler. Click on the word “Photo” in the caption for each of Mike’s photographs to see his original Facebook post for that image.

Every species features the following information: common name; scientific name; early-date/late-date; abundance; and habitat. All information is excerpted from “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.


Dragonflies (Order Anisoptera)

Family Aeshnidae (Darners)

Black-tipped Darner (Aeshna tuberculifera)

Adult flight period: JUN 30 – OCT 29. Rare to uncommon. Habitat: Montane ponds.

Photo used with written permission from Michael Boatwright.

Common Green Darner (Anax junius)

Adult flight period: FEB 27 – DEC 30. Common. Habitat: Ponds.

Fawn Darner (Boyeria vinosa)

Adult flight period: JUN 03 – NOV 07. Common. Habitat: Streams, rivers.

Shadow Darner (Aeshna umbrosa)

Adult flight period: JUN 08 – DEC 05. Common. Habitat: Ponds, streams.

Family Corduliidae (Emeralds)

Clamp-tipped Emerald (Somatochlora tenebrosa)

Adult flight period: JUN 08 – OCT 15. Common. Habitat: Ponds, small streams.

Photo used with written permission from Michael Boatwright.

Fine-lined Emerald (Somatochlora filosa)

Adult flight period: JUL 10 – OCT 15. Rare to uncommon. Habitat: Boggy streams, swamps, marshes.

Family Gomphidae (Clubtails)

Arrow Clubtail (Stylurus spiniceps)

Adult flight period: JUN 13 – OCT 19. Uncommon to common. Habitat: Rivers.

Photo used with written permission from Michael Boatwright.

Laura’s Clubtail (Stylurus laurae)

Adult flight period: JUN 20 – SEP 26. Rare to uncommon. Habitat: Streams, rivers.

Photo used with written permission from Michael Boatwright.

Russet-tipped Clubtail (Stylurus plagiatus)

Adult flight period: JUN 15 – NOV 06. Uncommon to common. Habitat: Streams, rivers.

Family Libellulidae (Skimmers)

Autumn Meadowhawk (Sympetrum vicinum)

Adult flight period: MAY 28 – JAN 03. Common. Habitat: Ponds.

Blue-faced Meadowhawk (Sympetrum ambiguum)

Adult flight period: MAY 22 – NOV 19. Uncommon. Habitat: Swamps, ponds.

Black Saddlebags (Tramea lacerata)

Adult flight period: APR 12 – OCT 30. Common. Habitat: Ponds.

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

Spot-winged Glider (Pantala hymenaea)

Adult flight period: MAY 08 – OCT 20. Common. Habitat: Ponds.

A Spot-winged Glider dragonfly (Pantala hymenaea) netted at Saint Louis Catholic School, Fairfax County, Virginia USA. This individual is a female.

20 JUL 2016 | Fairfax County, VA USA | Spot-winged Glider (female)

Wandering Glider (Pantala flavescens)

Adult flight period: MAY 02 – NOV 17. Common. Habitat: Ponds.

Damselflies (Order Zygoptera)

Family Lestidae (Spreadwings)

Great Spreadwing (Archilestes grandis)

Adult flight period: JUN 25 – NOV 11. Uncommon. Habitat: Streams, ponds.

Spotted Spreadwing (Lestes congener)

Adult flight period: JUN 10 – NOV 11. Uncommon. Habitat: Ponds.

Photo used with written permission from Michael Boatwright.

 


Classification of Fall Species into Sub-groups

Migratory Species

At least five major species of dragonflies known to be migratory in North America.

  • Black Saddlebags (Tramea lacerata)
  • Common Green Darner (Anax junius)
  • Spot-winged Glider (Pantala hymenaea)
  • Wandering Glider (Pantala flavescens)

Rare to Uncommon Species

  • Arrow Clubtail (Stylurus spiniceps)
  • Black-tipped Darner (Aeshna tuberculifera)
  • Blue-faced Meadowhawk (Sympetrum ambiguum)
  • Clamp-tipped Emerald (Somatochlora tenebrosa)
  • Fine-lined Emerald (Somatochlora filosa)
  • Laura’s Clubtail (Stylurus laurae)
  • Ocellated Darner (Boyeria grafiana)
  • Great Spreadwing (Archilestes grandis)
  • Spotted Spreadwing (Lestes congener)

Copyright © 2021 Walter Sanford. All rights reserved.

Neurocordulia yamaskanensis exuvia

April 13, 2020

A Stygian Shadowdragon dragonfly (Neurocordulia yamaskanensis) exuvia was collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Interstate Park, Polk County, Wisconsin USA.

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 (prementum) that covers the face, as shown in Image No. 1, characteristic of four families of odonates: Cordulegastridae (Spiketails); Corduliidae (Emeralds); Libellulidae (Skimmers); and Macromiidae (Cruisers).
  • There is no horn on the face-head, characteristic of Macromiidae, so it’s not a cruiser.
  • Cordulegastridae has angular, jagged crenulations on its labium, so it’s not a spiketail. The crenulations for Corduliidae and Libellulidae can look similar.
  • Look at the anal pyramid to differentiate Corduliidae and Libellulidae: 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, and no horn on its face-head. The deeply-scalloped crenulations along the margins of the palpal lobes are a characteristic field mark for Genus Neurocordulia (Shadowdragons) in the Family Corduliidae (Emeralds), according to Kevin Hemeon, member of the “Odonate Larvae and Exuviae” Facebook group.

Although the anal pyramid isn’t shown clearly in any of the photos in this field guide, careful examination of photos of the teneral adult that emerged from the exuvia (see The Backstory, below) confirmed the dragonfly is a Stygian Shadowdragon. Stygian is the only species of Neurocordulia (Shadowdragons) within range of Wisconsin.

A face-head view of the exuvia is shown in Image No. 1, magnified approximately two and one-half times life size (~2.5x). Notice the mask-like labium that covers the face of the exuvia, including deeply-scalloped crenulations with bundles of bristles (setae) located along the margins of the palpal lobes.

No. 1 | Neurocordulia yamaskanensis | exuvia (face-head)

Step 2. Genus and species

Dichotomous keys from Identification Keys to Northeastern Anisoptera Larvae, compiled by Ken Soltesz, were used to verify the genus and species of the exuvia. Field marks that match this specimen are highlighted in boldface green text.

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

1a. Pair of small tubercles on top of head; Lateral lobe of labium with 4 or 5 setae (except sometimes 6 or 7 in Neurocordulia). (2)

2a. Strong lateral spines of abdominal segment 8 very divergent and as strong as parallel spines of [S]9. (Neurocordulia)

Alternate Key to the Genera of the Family Corduliidae, p. 29.

1a. Dorsal hooks present and well developed on some of the abdominal segments. (2)

2a. Lateral spines present on segment 8. (3)

3a. Crenulations on distal margin of labial palpi nearly semicircular or even more deeply cut; Lateral spines on segment 8 divergent. (Neurocordulia)

Key to the Species of the Genus Neurocordulia, p. 31.

1b. Lateral spines of 9 about 30 to 50 percent of the length of segment 9, not extending beyond the tips of the caudal appendages; Dorsal hooks of segments 7 to 9 reduced to scarcely more than a short ridge; Length 22 – 24.5 mm. (yamaskanensis)

The following annotated focus-stacked composite images illustrate key field marks described in Soltesz’s dichotomous keys.

Notice the specimen has stubby mid-dorsal hooks along the length of its abdomen, as shown in Image No. 2.

Lateral spines are present on abdominal segments eight and nine (S8-S9): the lateral spines on S8 are divergent; the ones on S9 are parallel.

The exuvia is ~2.4 cm (~0.95 in) in length — the longest shadowdragon larva/exuvia in the genus Neurocordulia. Notice the lateral spines on abdominal segment nine (S9) don’t extend beyond the tips of the caudal appendages (terminal appendages), as shown below.

The Backstory

The following narrative was provided by Freda van den Broeck.

On the last morning of the Wisconsin Dragonfly Society Annual Meeting weekend — Sunday, June 10th 2019 — I made my way to the boat landing in Interstate Park, St. Croix Falls, Wisconsin USA.

The previous morning I’d photographed Mustached Clubtail emerging there (with Alon Coppens). We also saw several teneral Rapids Clubtails. One didn’t have to look hard to find exuviae — they were most easily seen on the rocks, just a couple of feet above the water line. I was really hoping to find a Snaketail emerging, but had no such luck.

Photo of St. Croix river used with permission from Freda van den Broek.

Just as I was about to head back to the car, I spotted a teneral, that had crawled up the rock face higher than I would have expected. At that point, I thought it was “just another baskettail” — we’d seen many of them on Friday afternoon and Saturday. But it was pretty and shiny, so I had to take a few pictures, even though I was late for breakfast. (It was around 8:20 am.)

It was several days later before I realized that it wasn’t a baskettail, but a Shadowdragon, and that a few of the exuviae I’d collected there were Stygian Shadowdragons. Source Credit: Freda van den Broek.

Photo used with permission from Freda van den Broek.

Tenerals are usually tough to identify, but you’ll notice in both photos that the [small yellow] spot on [side of] the thorax is clearly visible. Source Credit: Freda van den Broek.

Photo used with permission from Freda van den Broek.

Related Resources

Odonate Exuviae – a hyperlinked list of identification guides to many species of odonate exuviae from seven families of dragonflies and three families of damselflies.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – N. yamaskanensis exuvia (face-head)

April 10, 2020

The following annotated focus-stacked composite image shows a Stygian Shadowdragon dragonfly (Neurocordulia yamaskanensis) exuvia collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Interstate Park, Polk County, Wisconsin USA.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

Notice the unusual shape of the crenulations between the palpal lobes of its mask-like labium. Is this field mark unique to N. yamaskanensis or common to all species of the genus Neurocordulia (Shadowdragons)? Enquiring minds want to know!

Tech Tips

Laowa 25mm Ultra Macro lens, set for 2.5x magnification, and Canon EOS 5D Mark II DSPLR was used to photograph the subject against a pure white background (255, 255, 255) following the “Meet Your Neighbours” (MYN) technique.

24 photos were used to create the composite image, including 23 photos taken using an aperture of f/5.6 and one photo taken at f/16.

If you look closely at the full-size version of the image, then you will notice some areas that indicate the final image is a few layers short of a perfect focus stack. But hey, not bad for a new lens and a manual focus rail that I used for the first time!

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – N. yamaskanensis exuvia (dorsal, ventral)

April 8, 2020

A Stygian Shadowdragon dragonfly (Neurocordulia yamaskanensis) exuvia was collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Interstate Park, Polk County, Wisconsin USA.

Dorsal

The first dorsal view is a square crop of the full-size version of a focus-stacked composite image of the subject. Notice the specimen has stubby mid-dorsal hooks along the length of its abdomen and lateral spines on abdominal segments eight (S8) and nine (S9).

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

The original full-size image, shown below, was straightened and cropped slightly.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

Ventral

The first ventral view is a square crop of the full-size version of a focus-stacked composite image of the subject. Notice the compact size of the prementum, and its unusual shape.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

The original full-size image, shown below, was cropped slightly.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

Related Resources

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

Three (3) photos were used to create the dorsal composite image, including a single photo focused on the head/thorax, and two places along the abdomen (S5-S6 and S9).

13 photos were used to create the ventral composite image, including multiple photos focused on the prementum, thorax, and two places along the abdomen (S3-S4; S7-S8).

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – N. yamaskanensis exuvia (dorsal-lateral)

April 6, 2020

The following focus-stacked composite image shows a dorsallateral view of a Stygian Shadowdragon dragonfly (Neurocordulia yamaskanensis) exuvia collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Interstate Park, Polk County, Wisconsin USA.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

Notice the specimen has stubby mid-dorsal hooks along the length of its abdomen and lateral spines on abdominal segments eight (S8) and nine (S9).

Related Resources

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

Four (4) photos were used to create the composite image, including a single photo focused on the head, thorax, and two places along the abdomen (S6-S7 and S9-S10).

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Focus-stacked composite image

April 3, 2020

The following focus-stacked composite image shows a Stygian Shadowdragon dragonfly (Neurocordulia yamaskanensisexuvia collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Interstate Park, Polk County, Wisconsin USA.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

Related Resources

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

24 photos were used to create the composite image, including 23 photos taken using an aperture of f/5.6 and one photo taken at f/16.

If you look closely at the full-size version of the image, then you will notice some areas that indicate the final image is a few layers short of a perfect focus stack. But hey, not bad for a new lens and a manual focus rail that I used for the first time!

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Stygian Shadowdragon exuvia

March 30, 2020

A Stygian Shadowdragon dragonfly (Neurocordulia yamaskanensis) exuvia was collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Interstate Park, Polk County, Wisconsin USA.

Stygian is the only species of Neurocordulia (Shadowdragons) within range of Wisconsin.

10 JUN 2019 | Polk County, WI | Stygian Shadowdragon (exuvia)

Notice the interesting crenulations on the labium (face mask) of the exuvia, including bundles of bristles (setae) along the margins of the palpal lobes.

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

I set the Laowa 25mm Ultra Macro lens for 2.5x magnification and an aperture of f/5.6, then took some test shots of the subject. Next I shot 23 photos for a focus-stacked composite image showing the face-head-dorsal view of this specimen.

Finally I shot a few photos at f/16, focused manually on the face mask. At the time of this writing, it was too late to create the focus stack so here’s one of the shots at f/16. An aperture of either f/5.6 or f/8 is the “sweet spot” for this lens, according to video reviews I watched. The net result — some image sharpness was sacrificed in favor of more depth of field.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Unknown dragonfly exuvia (redux)

February 26, 2020

This blog post features more photos of an exuvia from an unknown species of odonate that was collected by Joe Johnston on 07 August 2019 along Aquia Creek at Channel Marker No. 34, Stafford County, Virginia USA.

The specimen is probably from either Family Corduliidae (Emeralds) or Family Libellulidae (Skimmers).

07 AUG 2019 | Aquia Creek | dragonfly exuvia (dorsal view)

The rule of thumb for differentiating Corduliidae exuviae from Libellulidae is as follows: It’s probably Corduliidae if the cerci are at least half as long as the paraprocts; it’s probably Libellulidae if the cerci are less than half the length of the paraprocts.

07 AUG 2019 | Aquia Creek | dragonfly exuvia (ventral view)

I’m having a hard time seeing the cerci clearly. If I’m seeing what I think I’m seeing, then the cerci are at least half as long as the paraprocts and the exuvia is from Family Corduliidae (Emeralds).

In order to verify my tentative identification, I need to use a higher magnification macro lens (such as my Canon MP-E 65mm Macro lens) in order to shoot a close-up view of the anal pyramid/terminal appendages (see inset diagram, lower-left corner).

Related Resource: MYN – Dragonfly exuvia (unknown species)

Tech Tips

This specimen was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. I used the new variation on my old MYN studio rig and I’m still satisfied with the results.

Copyright © 2020 Walter Sanford. All rights reserved.

Final Fine-lined Emerald

October 7, 2019

Several Fine-lined Emerald dragonflies (Somatochlora filosa) were spotted during a photowalk with Michael Powell at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. At least six S. filosa were spotted along two dirt/gravel roads at the refuge; this is the last one we saw.

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

Decisions, decisions!

I shot 37 photographs of the following dragonfly perched in several places: two photos are out of focus; most of the rest are flawed in some way (in my opinion), for example I don’t like the background, or the composition, etc.

As it turns out, the last group of photos is my favorite. Within that group, I selected a subset of three photos that I like. Although the photos are similar, they are subtly different. I think one of the images is the clear winner, but I suffer from decision paralysis sometimes. The photos are shown in the order in which they were taken. Which one is your favorite?

No.1

No. 2

No. 3

Sidestory

I think I might have figured out the habitat/breeding habitat for Fine-lined Emerald dragonflies. As Mike Powell and I were walking along one of several roads at Occoquan Bay NWR that lead to hotspots for hunting Fine-lined Emerald, I noticed shallow pools of “black water” in the forest, beginning about halfway down one of the dirt/gravel roads at the park. I mentioned to Mike that I think the black water pools are habitat for S. filosa.

Sure enough, that’s exactly where we spotted the male featured in this post — the last one we saw as we were walking back to Mike’s car. It’s worth noting we have never seen a Fine-lined Emerald that far from the main hotspots. Mike saw several more S. filosa in the same area a few days later. Hey, I might be onto something!

Copyright © 2019 Walter Sanford. All rights reserved.

Yet another male Fine-lined Emerald

September 30, 2019

The following images show the third Fine-lined Emerald dragonfly (Somatochlora filosa) that I photographed during a photowalk on 18 September 2019 at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual is a male, as indicated by his “indented” hind wings and terminal appendages. The following photo shows both field marks clearly.

Personality

Do dragonflies have personality? Who knows? I’ll say this: Some individuals within the same species seem to behave in ways that are distinctly observable and slightly atypical.

For example, this guy was hyperactive. He flew from perch-to-perch as though he were searching for the perfect perch. After brief stops at several spots, he disappeared into the tree canopy.

Before Mike Powell and I spotted the male featured in this post, we watched another male patrol back-and-forth between us for more than 30 minutes without landing! Mike and I were standing along a dirt/gravel road, about 20-30 yards apart. We had a lot of fun “redirecting” the dragonfly in the opposite direction toward each other. Several times the dragonfly “pulled up” in front of me and appeared to be thinking about landing on my head, but we were never so lucky. Eventually, the male must have tired of the game because he simply vanished!

Perhaps I’m guilty of personification of dragonflies, but I think they have lots of personality!

Copyright © 2019 Walter Sanford. All rights reserved.


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