Posts Tagged ‘Cruiser Family’

Stream Cruiser dragonfly (female)

April 23, 2016

The following photograph shows a Stream Cruiser dragonfly (Didymops transversa) spotted on 20 April 2016 as I was photowalking along a trail at Accotink Bay Wildlife Refuge.

Key field marks for Didymops transversa include a white facial bar and a single white stripe on the side of the thorax. Male– and female Stream Cruisers are similar in appearance. This individual is a female as indicated by the pair of white terminal appendages (cerci) clearly visible at the end of her abdomen.

A Stream Cruiser dragonfly (Didymops transversa) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

I shot lots of photos of this individual, including many good- to very good shots. This image is one of my favorites. When editing photographs of dragonflies that like to perch in places where the background is cluttered, usually it is necessary to crop the original image. Not this photo — it is uncropped because the subject fills the frame and the composition looks good as is.

I plan to post more photos of Stream Cruiser dragonflies, including this female as well as several males spotted on the same day.

Copyright © 2016 Walter Sanford. All rights reserved.

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.

A sampler of male dragonfly claspers (Part 1)

March 16, 2015

All 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”). Claspers come in a variety of shapes and sizes, but their function is identical for all species of dragonflies.

There are seven families of dragonflies. Part 1 (of 2) features a sampler of select images showing male dragonfly claspers from the Clubtail Family, Cruiser Family, and Darner Family.

Clubtail Family

The following image shows a male Ashy Clubtail dragonfly (Gomphus lividus) perching on the ground in a field located near Giles Run at Meadowood Recreation Area in Fairfax County, Virginia.

Ashy- or Lancet Clubtail

02 MAY 2014 | Meadowood Recreation Area | Ashy Clubtail (male)

Cruiser Family

The next image shows a male Stream Cruiser dragonfly (Didymops transversa) spotted along “Beaver Pond Loop Trail” at Accotink Bay Wildlife Refuge, a 1,200 acre preserve located at Army Garrison Fort Belvoir, Fairfax County, Virginia.

Stream Cruiser dragonfly (male)

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

Darner Family

The last image shows a male Shadow Darner dragonfly (Aeshna umbrosa) spotted near a vernal pool in the forest at Huntley Meadows Park.

Shadow Darner dragonfly (male)

24 OCT2014 | Huntley Meadows Park | Shadow Darner (male)

Related Resources:

Editor’s Notes: Part 2 (of 2) will feature a sampler of select images showing male dragonfly 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.

Copyright © 2015 Walter Sanford. All rights reserved.

Stream Cruiser dragonfly (female)

May 22, 2014

The following photograph shows a Stream Cruiser dragonfly (Didymops transversa) spotted as I was photowalking along a dirt trail at Meadowood Recreation Area on 08 May 2014.

Male– and female Stream Cruisers are very similar in appearance: a white facial bar and a single white stripe on the side of the thorax are key characteristics of Didymops transversa. This individual is a female as indicated by the pair of white terminal appendages (cerci) clearly visible at the end of its abdomen.

Stream Cruiser dragonfly (female)

Thanks to Mr. Chris Hobson, Natural Areas Zoologist with the Virginia Natural Heritage Program, Virginia Department of Conservation and Recreation, for providing species descriptors paraphrased in this post.

Copyright © 2014 Walter Sanford. All rights reserved.

Stream Cruiser dragonfly (male), redux

June 13, 2013

The following photographs show a Stream Cruiser dragonfly (Didymops transversa) spotted along “Beaver Pond Loop Trail” at Accotink Bay Wildlife Refuge, a 1,200 acre preserve located at Army Garrison Fort Belvoir, Fairfax County, Virginia USA. This individual is a male as indicated by the white terminal appendages at the end of its abdomen. The abdomen of male Stream Cruisers is enlarged near the tip, similar to the Clubtail family of dragonflies.

Stream Cruiser dragonfly (male) Stream Cruiser dragonfly (male)

Copyright © 2013 Walter Sanford. All rights reserved.

Stream Cruiser dragonfly (male)

April 30, 2013

The following photo gallery features a Stream Cruiser dragonfly (Didymops transversa) spotted along “Beaver Pond Loop Trail” at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a male as indicated by the white terminal appendages at the end of its abdomen. The abdomen of male Stream Cruisers is enlarged near the tip, similar to the Clubtail family of dragonflies.

Thanks to Mr. Chris Hobson, Natural Areas Zoologist with the Virginia Natural Heritage Program, Virginia Department of Conservation and Recreation, for verifying my tentative identification and for providing species descriptors paraphrased in this post.

Copyright © 2013 Walter Sanford. All rights reserved.

Stream Cruiser dragonfly (female)

April 27, 2013

The following photo gallery features a Stream Cruiser dragonfly (Didymops transversa) spotted along the upper segment of “Loop Trail” at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA.

Male– and female Stream Cruisers are very similar in appearance: a white facial bar and a single white stripe on the side of the thorax are key characteristics of Didymops transversa. This individual is a female as indicated by the pair of white terminal appendages (cerci) at the end of its abdomen. Notice the differences between female- and male terminal appendages, as shown in the following slideshow. See a full-size version of the composite image shown in Slide 2: female appendages are shown in the background photo; male appendages are shown in the inset photo.

This slideshow requires JavaScript.

Thanks to Mr. Chris Hobson, Natural Areas Zoologist with the Virginia Natural Heritage Program, Virginia Department of Conservation and Recreation, for providing species descriptors paraphrased in this post.

Related Resources: Odonate Terminal Appendages.

Copyright © 2013 Walter Sanford. All rights reserved.


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