Posts Tagged ‘Spiketail Family’

Can I see some eye-dentification?

March 20, 2015

It may seem like all dragonflies look alike when you’re beginning to learn how to identify dragonflies. For example, all dragonflies have large, multifaceted compound eyes. Look closely. Careful observation of the color, shape, and size of eyes should enable you to quickly identify the family (or families) of dragonflies to which a specimen may belong.

The following field markers — used in combination with a good field guide to dragonflies, a species list for your location, and the process of elimination — should enable you to identify unknown specimens more quickly than randomly trying to find a match between your specimen and one of the 316 of species of dragonflies known to occur in the United States!

Clubtail Family (and Petaltail Family)

The eyes of clubtail dragonflies (and petaltails) are widely separated, somewhat similar to the eyes of damselflies. The Clubtail Family is the second largest family of dragonflies, so this field marker should be useful for identifying a lot of dragonflies to the family level — if only clubtails were as easy to identify down to the species level!

Ashy- or Lancet Clubtail dragonfly

09 MAY 2013 | Meadowood Recreation Area | Ashy/Lancet Clubtail (female)

The preceding dragonfly is either an Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphis exilis). Ashy- and Lancet Clubtail dragonflies are similar in appearance and difficult to differentiate with complete certainty. But one look at those eyes and you know it’s definitely some species of clubtail!

Spiketail Family

Notice the eyes of the following dragonfly nearly touch at a point between its eyes — that’s a distinctive field marker for the Spiketail Family.

Brown Spiketail dragonfly (female)

09 MAY 2013 | Meadowood Recreation Area | Brown Spiketail (female)

Cruiser, Emerald, and Skimmer Families

In a few families of dragonflies, the eyes meet along a short seam near the face.

The Skimmer Family is the largest family of dragonflies. Many species of Skimmers are common and fairly easy to identify.

There are fewer species of dragonflies in the Cruiser Family than the Skimmer Family; no other dragonflies in the United States look similar to cruisers.

Stream Cruiser dragonfly (male)

02 MAY 2013 | Accotink Bay Wildlife Refuge | Stream Cruiser (male)

Many species of the Emerald Family feature distinctive bright green eyes, hence the family name.

Mocha Emerald dragonfly (Somatochlora linearis)

25 JUL 2012 | The Wildlife Sanctuary | Mocha Emerald (male)

Darner Family

The eyes of Darners meet along a long seam from front-to-back.

Common Green Darner dragonflies (mating pair, in tandem)

14 AUG 2012 | Huntley Meadows Park | Common Green Darner (mating pair)

Self-test

OK, let’s apply what you just learned. Looking at the eyes only, can you identify the family for the following dragonfly? If you would like to know whether your answer is correct, then please leave a comment.

Teacher’s Note: In order to avoid revealing the answer to the one-question quiz as soon as the first person comments, I changed the settings for this blog so that comments must be approved manually.

Common Sanddragon dragonfly (male)

26 JUN 2015 | Wickford Park | [Insert family name here.]

Editor’s Notes: This post is adapted from Dragonfly Head & Eyes, one of many excellent guides on the Odes for Beginners Web site. Thanks for the inspiration, Sheryl Chacon!

Copyright © 2015 Walter Sanford. All rights reserved.

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A sampler of male dragonfly claspers (Part 2)

March 18, 2015

The theme of the “sampler series” is simple. Male dragonfly claspers come in a variety of shapes and sizes, but their function is identical for all species of dragonflies: male dragonflies use their claspers to grab and hold female dragonflies during mating.

There are seven families of dragonflies. Part 2 (of 2) features a sampler of select images showing male dragonfly claspers from the Emerald Family, Skimmer Family, and Spiketail Family. The author never has been fortunate to photograph either species of the Petaltail Family.

Emerald Family

The following image shows a Slender Baskettail dragonfly (Epitheca costalis) spotted in an open field along the trail to Hidden Pond, a small lake located at Meadowood Recreation Area.

Slender Baskettail dragonfly (male)

01 MAY 2013 | Meadowood Recreation Area | Slender Baskettail (male)

Skimmer Family

The next image shows a Bar-winged Skimmer dragonfly (Libellula axilena) spotted near a vernal pool in the forest at Huntley Meadows Park. Many members of the Skimmer Family have terminal appendages that look similar to the Bar-winged Skimmer, such as Painted Skimmer, Eastern Pondhawk, and Blue-faced Meadowhawk, to name a few species.

Bar-winged Skimmer dragonfly (young adult male)

31 MAY 2014 | Huntley Meadows Park | Bar-winged Skimmer (male)

The following image shows a battle-scarred Black Saddlebags dragonfly (Tramea lacerata) spotted alongside the boardwalk in the central wetland area hemi-marsh at Huntley Meadows Park. Black Saddlebags’ terminal appendages are unlike most members of the Skimmer Family.

Black Saddlebags dragonfly (male)

12 SEP 2014 | Huntley Meadows Park | Black Saddlebags (male)

Spiketail Family

The last image shows an Arrowhead Spiketail dragonfly (Cordulegaster obliqua) I discovered while exploring a small stream at a remote location in Huntley Meadows Park.

Arrowhead Spiketail dragonfly (male)

07 JUL 2014 | Huntley Meadows Park | Arrowhead Spiketail (male)

Related Resources:

Editor’s Notes: Part 1 (of 2) features a sampler of select images showing male dragonfly dragonfly claspers from the Clubtail Family, Cruiser Family, and Darner Family. The author has never been fortunate to photograph either species of the Petaltail Family.

Copyright © 2015 Walter Sanford. All rights reserved.

Arrowhead Spiketail dragonfly (male)

July 9, 2014

On 07 July 2014, I discovered an Arrowhead Spiketail dragonfly (Cordulegaster obliqua) while exploring a small stream at a remote location in Huntley Meadows Park. Arrowhead Spiketails are an uncommon species of dragonfly formerly unknown to occur at Huntley Meadows Park. According to Kevin Munroe, Park Manager at Huntley Meadows and author of Dragonflies of Northern Virginia, my discovery sets a new flight record for the latest date Arrowhead Spiketails have been observed in Northern Virginia.

I noticed the Arrowhead Spiketail as it patrolled back-and-forth down the middle of the stream, about six inches (6”) above the water. After hours of searching, I discovered a location near one end of the dragonfly’s long flight path where it stopped to perch several times.

This individual is a male, as indicated by its terminal appendages and the “indentations” on its hind wings (near the body). [See “Related Resources,” below, for images that show female terminal appendages (notice the ovipositor visible between her cerci) and hind wing shape (rounded rather than indented).]

Arrowhead Spiketail dragonfly (male)

Arrowhead Spiketail dragonfly (male)

Arrowhead Spiketail dragonfly (male)

Arrowhead Spiketail dragonfly (male)

The blue orb located near the upper-right side of the following photo is probably an artifact of my camera flash rather than a ghostly apparition.

Arrowhead Spiketail dragonfly (male)

Arrowhead Spiketail dragonfly (male)

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

  • Genus Cordulegaster | Cordulegester obliqua | Arrowhead Spiketail | male | top view
  • Genus Cordulegaster | Cordulegester obliqua | Arrowhead Spiketail | female | top view
  • Genus Cordulegaster | Cordulegester obliqua | Arrowhead Spiketail | female | side view

Editor’s Note:Odonatacoccygia” is defined as seeing shapes in the patterns on odonates, and I should know, since I coined the term! Look at the yellow markings on top of the thorax, shown best in the full-size version of Photo 1. Do you see a bucktooth Energizer Bunny® (wearing sunglasses)? I do!

Copyright © 2014 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (female)

May 26, 2013

The following photo gallery shows a female Brown Spiketail dragonfly (Cordulegaster bilineata) spotted on 09 May 2013, perching near the ground in an open field along the trail to Hidden Pond, a small lake located at Meadowood Recreation Area in Fairfax County, Virginia USA.

Why are Spiketail dragonflies called “spiketails,” and what field markers can be used to identify this individual as a female? The answer to both questions is illustrated in the following annotated close-up photograph of the posterior end of the Brown Spiketail dragonfly’s abdomen.

Brown-Spiketail_f_anatomy

All female dragonflies have a pair of cerci (superior appendages) that have little or no function. Notice the spike-shaped subgenital plate.

Spiketail dragonflies are so named because the female’s long [subgenital plate], or egg-laying organ, extends beyond the tip of the abdomen. Source Credit: New York State Department of Environmental Conservation.

Thanks to Richard Orr, renowned expert on dragonflies and damselflies of the mid-Atlantic region, for verifying my tentative indentification of both the gender of the dragonfly and some of its anatomical parts.

Related Resources: Odonate Terminal Appendages.

Copyright © 2013 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (redux)

May 12, 2013

This Brown Spiketail dragonfly (Cordulegaster bilineata) has a face only a mother could love. Happy Mother’s Day!

Brown Spiketail dragonfly (female) Brown Spiketail dragonfly (female)

Copyright © 2013 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly

May 7, 2013

The following photo gallery shows a Brown Spiketail dragonfly (Cordulegaster bilineata) perching near the ground. This individual is a female as indicated by its terminal appendages and spike-shaped ovipositor on the underside of its abdomen (posterior end).

This specimen was spotted in an open field along the trail to Hidden Pond, a small lake located at Meadowood Recreation Area in Fairfax County, Virginia USA.

Copyright © 2013 Walter Sanford. All rights reserved.


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