Monday, June 6, 2011

A Few Ecuadorian Odonates

I haven’t posted anything here for a while since I started preparations for a trip to Ecuador and the Galapagos Islands. I intended to publish something right before I left and have another post scheduled to publish while I was gone in order to keep the content flowing, but things just got too hectic.

This wasn’t a dedicated odonate trip like I’ve done before—it was more of a touristy, relax and enjoy the culture, see some new places and wildlife sort of trip. I’ve been to the Ecuador mainland before, but this was my first trip to the Galapagos and it was a blast!

Naturally, no matter where I go I’m on the lookout for odonates, and this trip was no exception. I didn’t see very much, however. The mainland weather was rather cool (relatively) and cloudy much of the time, so there just wasn’t a lot flying. I saw a couple of species flying about the scrub on the Galapagos Islands—species that are strong fliers which are able to set up shop on distant oceanic islands, so these were on the mainland too and didn’t really get my juices flowing. I never got to any freshwater wetlands on the islands where there might be more interesting odonates.

While on the mainland, things came together for a few hours one morning in the Zamora area: lots of forest, lots of beautiful streams, and some glorious, radiant sun. This gave me an opportunity to find and photograph some really interesting odonates on the Amazon slope of the Andes. Here are a few . . .




Argia sp.

Argia is the most speciose genus of damselflies in the New World, and they are at their most diverse in the tropics. The problem is that the tropical species, particularly in South America, are in serious need of a revision (which is apparently underway). Some species are pretty straightforward and well understood taxonomically, some are rather confusing (and may be complexes of multiple species), and there are a number of species which are known, but not yet described. On top of all that, there are certainly more species which are yet to be discovered.

There were a number of individuals of the Argia above, with the mostly dark abdomen and brown humeral (or “shoulder”) stripe on the thorax. They were mostly around small, rocky, sun-dappled streams (often with a little waterfall) under forest canopy. It may be A. gerhardi, or maybe it’s one of those known, but not yet described species, or maybe it’s something totally new.


Polythore terminata

Polythore terminata is a large, conspicuous, and fairly common species of forested streams in the Zamora area. Males (like the individual above) are distinctive with their black tips on otherwise clear wings (like they were dipped in ink). I love the black thorax with white pin stripes. On females, the black on the wings don’t quite make it all the way to the tips.



Philogenia sp.

The Philogenia are real shade lovers and this guy was hanging out under a canopy of leafy vegetation near a small waterfall stream. This is a damselfly, but like most members of its family—Megapodagrionidae, they perch with their wings wide open. This species is pretty typical of the genus with its dull earth tone coloration except for the conspicuous patch of nearly white pruinescence near the tip of the abdomen. I don’t know which species it is, however. I thought it might be P. redunca, but the abdominal appendages are clearly wrong. It may be undescribed.



Archaeopodagrion armatum

This was only the second time this species has been seen alive. Ken Tennessen and I first discovered it in 2008 and we published the description in 2010. It was fun to go back and find them flying very close to the location of discovery (within about a hundred yards, actually). There are only two other species of Archaeopodagrion known—both from Ecuador, described by Clarence Kennedy in 1939 and 1946. One of them was not seen again until just a few years ago (A. bicorne) and I think the other still has not been refound (A. bilobatum). It was quite a shock to find a third species of this mysterious genus.

I saw several individuals along a little trickle of water that flowed on a section of trail just before it joined a small stream below a waterfall. Like the Philogenia above, this is a real shade lover. The only time I saw individuals out in the open flying above the trickle of water was when the sun was hidden by clouds. When the sun was out, they disappeared. During one of those sunny moments, I lifted a large leaf and found an individual perching back in the dark, safely protected from UV rays.

Also like the Philogenia, Archaeopodagrion is a damselfly in the family Megapodagrionidae and perch with the wings wide open. Archaeopodagrion is even more cryptically colored with it’s earth tones and a bit of dull yellow patterning. This species in particular has conspicuous “flaps” on the prothorax (you can just make out one behind the right eye). The male’s abdominal appendages are pretty unusual too. If you’d like to see the description, you can view a PDF here.

I hope this whet your appetite for tropical odonates which are extremely interesting and very much in need of greater understanding. A previous post profiled the stunning Zenithoptera lanei and I’ll occasionally write about other tropical odonates that I have encountered during my travels. They’re not in “my” Pacific Northwest, but Ecuador is in northwestern South America!

2 comments:

  1. Thanks, Jim,

    Really cool window into another world (and great photos)!

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  2. @Chris Hill Thanks very much for the comment, Chris!

    ReplyDelete