I brought specimens of Gnamptogenys concinna and Lachnomyrmex scrobiculatus, both of which were definitely identified correctly. I owe the identification of the Gnamptogenys to Dr. Longino's website, The Ants of Costa Rica. I was randomly surfing through some photos and came across G. concinna, which is so distinctive I knew immediately it was the same species as a couple of my specimens that I had previously been unable to identify. I had originally IDd these ants as Gnamptogenys but they are so much larger than the rest of my Gnamoptogenys that I thought I must be wrong, at which point I stuck them with my Acanthoponera because of the petiole shape. But I couldn't match it up with any known species. So I put it aside and decided to worry about them later, but am pleased to have IDd them at last.
I am trying my best to be as honest and detailed as possible about where I have gone wrong in my IDing, because I think this will be helpful for others. I hope this isn't too tedious for anyone else reading this. I suspect it will be a relief to anyone who has had similar frustrations.
I also brought with me a specimen which I had identified as Talaridris mandibularis. But when I got a look at the specimen of T. mandibularis (the only species in the genus), it was clearly wrong. So back I went to Bolton, and decided it must be a Rhopalothrix, even though the mandible dentition did not seem quite right. As it happens I have only one other specimen of Rhopalothrix, a queen, and I took a quick superficial look at both of them and decided they must be the same species. Since I had already confirmed (by looking at every species of Rhopalothrix at Harvard -- and convincing myself that the ones that weren't at Harvard couldn't possibly by the same -- and seeing that it looked nothing like my queen) that it was a new species, I asked Stefan to take a look and confirm for me that they were the same species. They were definitely not. He seemed fascinated by the queen which has some sort of labial plate which no other Rhopalothrix has. And he was even more interested in the worker, because of the mandibular dentition, which didn't seem quite to be like the classic Rhopalothrix dentition (this, of course, made me feel good about my original misidentification). So anyway, that was pretty cool. Maybe I will describe them as new species (in all my copious free time).
Of course I did other stuff as well. I went through all my Megalomyrmex and confirmed all the identifications. I have one new species for sure. I also took pictures of all my ants, which can be seen (eventually) at my research webpage: http://people.bu.edu/karitr/AntSubfamilies.html