Hi if anyone knows more about this I would love to know. So on the night of the summer solstice this crab which we hardly ever see and is land based usually on its own formed a massive congregation, 1000’s of them climbed up the trees . I waited until the change of the tide and they crawled down and released their eggs with the outgoing tide. Then went back up . It was amazing.

As is typical for Gynacantha, this individual was trapped in a building. With a very slow approach, I was able to grab this guy by hand in the La Selva cafeteria.

I hoped it would be a Gynacantha I haven't seen before, but I believe the dark bar on the thorax and narrow S3 make this a Bar-sided Darner (Gynacantha mexicana) - a widespread tropical species.

La Selva Biological Station, Costa Rica

Exciting stuff! Two adults and a subadult tightly rolled up in duff under a stone, all three of whom refused to uncoil for me. A nearby board yielded a third adult who was kind enough to move around a bit.