Hi Steve, I think you are right about the genus - the very long thin legs, the long head and long projecting mandibles all point to Leptomyrmex. I'm pretty sure this is a male rather than a queen, and there is very little information on males to allow us to ID it to species. There are at least three species of Leptomyrmex we could get where you found this ant, including L. erythrocephalus, L. wiburdi and L nigriventris. Interestingly, though, if it was a queen, we could be sure of one thing - it can't be Leptomyrmex erythrocephalus, as this is one of the species in this genus which has "ergatoid" queens, which means the queens don't have wings, they just have to walk everywhere when they leave the nest to find a mate! There is some interesting reading at https://www.antwiki.org/wiki/Leptomyrmex_erythrocephalus. Good sighting. Cheers, Jon