Cyclophaea revisited

[Dennis Paulson]

Odonata - http://www.listbot.com/cgi-bin/subscriber

As the famous Cyclophaea cyanifrons (Euphaeidae) started a thread some time
ago, I finally sat down at the microscope to look again at this wondrous
beast with its long, pointed pseudoauricles.  First I discovered that, even
though the projections arch toward one another (nicely containing that
female abdomen tip), the tips abruptly point outward, so a female won't
skewer herself when she swings her abdomen up to copulate.

Second, the female looks no different from those of other euphaeids (I have
females of only a few species, but they all look about the same).

Third, of the 10 species of Euphaea I have in my collection, one (E.
amphicyana) has almost no trace of the pseudoauricles--nothing more than a
slight projection at the end of the 2nd segment.  The other 9 all have
quite well-developed projections (nothing remotely like Cyclophaea, of
course), in some cases with tiny teeth at their ends looking for all the
world like the teeth on the true auricles on some dragonflies.  I wouldn't
be at all surprised that they serve the same function.

Of great interest is that fact that on one species (E. subcostalis), the
seminal vesicle (a bulbous structure at the rear end of segment 2) has
pointed lateral projections that might serve the same function as the
pseudoauricles.  This species also has small pseudoauricles.  Looking at C.
cyanifrons again, I see that its seminal vesicle also has these
projections!  None of the other species in the family that I looked at had
other than smoothly rounded seminal vesicles.

I looked at males of 3 species of Anisopleura, in the same family, and all
3 have a transversely oriented ventrally directed ridge at the front edge
of segment 1.  This unique projection may also serve the same function, to
stop the female abdomen as it moves forward to contact the male genitalia.
None of the other genera have this.

Indophaea fraseri also has the pseudoauricles, but this may be a genus that
Andy Rehn thought was barely separable from Euphaea.  Three species of
Bayadera had no special modifications.  I've been unable to acquire a male
of the European Epallage fatime, so it still awaits scrutiny.

One interesting thing that I observed is that female euphaeids have much
shorter abdomens than males.  The discrepancy seems to me more than in any
other odonate family, and I wonder if this might have something to do with
the evolution of all these fancy structures for copulatory contact.

I apologize to those people on the list who may think that discussions such
as this, with technical terms and completely unfamiliar species, are
terribly arcane.  For you, as well as for everyone else, I have just
scanned a male and female Cyclophaea cyanifrons from Palawan and a male
Euphaea subcostalis from Borneo and put them on the web at:

        www.ups.edu/biology/museum/Euphaeidae.jpg

Finally, thanks to Matti Hämäläinen and Rosser Garrison, who sent me
specimens of several species of euphaeids in the past year.  Those gifts
bore intellectual fruit!

Dennis Paulson, Director                           phone 253-756-3798
Slater Museum of Natural History                 fax 253-756-3352
University of Puget Sound                       e-mail dpaulson@ups.edu
Tacoma, WA 98416
http://www.ups.edu/biology/museum/museum.html


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