Originally posted 19 January.
Updated with expert input from Dennis Paulson 20 January.
More info on the gomphid on 21 January.
John Abbott weighed in on 22 January.
Another adjustment to the gomphid on 29 January.
4 February: Nick Donnelly offers an opinion on the gomphid.
Additional comments welcome! Captions follow photos.
The two photos above are not the best or of the neatest-looking damselflies, but are probably our most interesting. They are of Anisagrion kennedyi, taken along the Rio Chevo at Finca Hartmann, Palo Verde section, Santa Clara, Panama (12 Jan 2008 by me, top; and 11 Jan 2008 by Stylurus, bottom). According to Dennis, who identified this for us, these are likely the first photos of this species.
Hetaerina cruentata along the Rio Chevo at Finca Hartmann, Palo Verde section, Santa Clara, Panama. 11 Jan 2008.
Camera in right hand, I was able to slowly sneak up on this rubyspot and grab it by the wings with my left hand (proud moment). That enabled me to take a close-up of the distinctive metallic green spot on the thorax that is characteristic of this species.
This rubyspot is Hetaerina miniata. I keyed out the females to reach the identification. Pipeline Road, Gamboa, Panama.
Flame-tailed Pondhawk, Erythemis peruviana. Pipeline Road, Gamboa, Panama. 8 Jan 2008.
Cardinal Meadowhawk, Sympetrum illotum. Finca Hartmann Ojo de Agua section, Santa Clara, Chiriqui, Panama. Too much glare off the water behind it. 12 Jan 2008.
Orthemis levis. Pond at Metropolitan Nature Park, Panama City, Panama. 6 Jun 2008.
Pallid Amberwing, Perithemis mooma. Pond at Metropolitan Nature Park, Panama City, Panama. Many female amberwings of most species have highly patterened wings. This one was quite plain. Amberwings stay coupled very briefly. In the thousands of amberwings I've seen, most have been single males. 6 Jan 2008.
Enough of the red and orange theme.
Pin-tailed Pondhawk, Erythemis plebeja. Pipeline Road, Panama. 8 Jan 2008.
Mature female Black Pondhawk, Erythemis attala. Pipeline Road, Gamboa, Panama. 7 January 2008.
Not-so-mature female Black Pondhawk, Erythemis attala. Pipeline Road, Gamboa, Panama. 7 Jan 2008.
Mangrove Darner, Coryphaeschna viriditas. Pipeline Road, Gamboa, Panama. 6 Jan 2008.
You know from my previous trip how much I like helicopter damselflies. We saw only one of the big Megaloprepus caerulatus, but saw quite a few of this species, Mecistogaster linearis, nearly all females. This one was preoccupied eating, and I was able to catch her to photograph her. She resumed her meal when we let her go! Pipeline Road, Gamboa, Panama. 7 Jan 2008.
Evening Skimmer, Tholymis citrina. A crepuscular species, tough to photograph in the shade. Pipeline Road, Gamboa, Panama. 7 Jan 2008.
Dennis thinks this is Argia medullaris, common in Costa Rica. He said if he had to name it, he'd call it the "Electric-blue Dancer." My guide to Central American odes did not have this species listed in Panama. Finca Hartmann, Ojo de Agua section, Santa Clara, Panama. 12 Jan 2008.
I thought this might be Spine-tipped Dancer, Argia extranea. Dennis said I was correct, although the taxonomy of this species groups isn't all worked out, so it might be a closely related species. Finca Hartmann, Ojo de Agua, Santa Clara, Panama. 12 Jan 2008.
Protoneura amatoria. Over a deeper pool in the first stream crossing (Juan Grande) on Pipeline Road, Gamboa, 8 Jan 2008.
Red-faced Dragonlet, Erythrodiplax fusca. Pipeline Road, Gamboa, Panama. 8 Jan 2008.
Striped Firetail, Telebasis filiola. Pipeline Road, Gamboa, Panama. Face here and huge here. 8 Jan 2008.
Argia indicatrix. Metropolitan Nature Park, Panama City, Panama. 15 Jan 2008.
Blue-fronted Setwing, Dythemis multipunctata. Immature male. Pipeline Road, Gamboa, Panama. ID's by Dennis Paulson. 8 Jan 2008.
Another dasher, a female Micrathyria laevigata. Another look here, and a male from our last trip here. Pipeline Road, Gamboa, Panama. 8 Jan 2008.
Rhodopygia cardinalis, based on the basal spot on the hind wing, and wing veination of a fresher individual. Pipeline Road, Gamboa, Panama. 7 Jan 2008.
The mystery gomphid.
This was really cool, as there are not many tropical gomphids. I flushed this gomphid at the Juan Grande crossing on Pipeline Road, Gamboa, Panama (first stream, 2 km from gate) on 8 Jan 2008. Stylurus was able to catch it (we ended up catching several more odes by stealth and quick hands), so we got additional photos, including the face and claspers and wing veination.
I originally thought this might be Phyllocycla volsella. However, it is too large for this genus. Dennis Paulson had this to say:
"It's in the Aphylla-Phyllocycla-Phyllogomphoides group, but I'm not even sure of the genus. Gomphids are still the group of anisopterans that are most poorly known throughout much of the tropics, as many species fly only briefly during the rainy season. There are fewer species in the dry season, and they are often in that group."Nick Donnelly, however, also thought this looked like P. volsella, and his estimate of the size of volsella is a bit bigger than Paulson's. I'm leaning in this direction again.
I found amongst my literature a key to the Odonata of Barro Colorado Island in the Panama Canal, in Spanish . Here are the gomphids listed for BCI, which is not too far from Pipeline Road.
Epigomphus quadracies. This genus has 2-3 cubito-anal crossveins on the wing. Our individual has only one.
Phyllocycla volsella. The BCI keys notes this as occurring in June and July, but that it is abundant along the Rio Frijoles (which is on the mainland near Pipeline Road) during the first months of winter.
Phyllogomphoides appendiculatus. According to my original key , the thoracic pattern of this species would not be as completely and strongly striped, and the inferior appendages should be easily visible in the dorsal view, which they are not. The BCI key says it is yellow and black (not green) and is found in late summer and early winter. It also mentions an undescribed Phyllogomphoides species that comes out in June and July with wide yellowish or greenish stripes on the top of the thorax.
Aphylla obscura. This is an interesting possibility to me, although my original key  indicates the flanges on segment 8 should be smaller and the "anterior half of dorsum of abdominal segment 7 not pale, but the same color as the posterior half." It is pale on ours. The thoracic pattern looks good, though. The BCI key  notes that this is a large species that emerges in the forest as early as February or March, that the thorax is well marked with black and green, and that the extreme tip of the abdomen is reddish (I also tracked down a description by Fred Sibley that notes this coloration). Ours does have warm tones on the tip of the abdomen, although I'm not so sure I'd say it's reddish. Donnelly agrees our bug is not this species.
Just more food for thought, and an attempt to keep all my info in one place!
This is one I forgot to add to the first post, and it remains unidentified. Plantation Road, near Gamboa, Panama. 7 January 2008.
These are apparently not identifiable via photos.
Unidentified Argia which is not, as I thought it might be, A. pulla or frequentula. Shot of the claspers and another shot by Stylurus here. Along the Rio Chevo at Finca Hartmann, Palo Verde section, Santa Clara, Panama. 11 Jan 2008.
I'm not sure these are the same species. We saw quite a few females, mostly at the Metropolitan Nature Park in Panama City (first photo 6 Jan 2008). The bottom photo was from Pipeline Road, Gamboa, 7 Jan 2008.
This is similar to the first unidentified one, but it has more black on the thorax. Metropolitan Nature Park, Panama City, Panama. 15 Jan 2008.
 Lista Preliminar de Nombre y Clave para Identificar los Odonata (Caballitos) de la Isla de Barro Colorado. Michael May, translated by C. L. Castro. Smithsonian Tropical Research Institute, 1979.
 The Dragonflies of Central America, exclusive of Mexico and the West Indies. A Guide to their Identification, 2nd Ed. Steffen Forster. Gunnar Rehfeldt, 2001.