This is a red damsel. There are apparently two recognized species, the eastern red damsel, Amphiagrion saucium, and the western red damsel, A. abbreviatum. According to the Iowa Dragonflies and Damselflies web site, the ones found in Iowa are intermediate between the two. I don’t know what the differences are. More work may determine that the two are one species, or that there are in fact three species.
This damselfly is not often seen. I have found in near very small streams of very clear water. It may be more common than it appears to be because of its secretive habits.