Triops longicaudatus male showing its flat carapace

Males tend to have a smaller, flatter carapace than the females of the same species, but they also usually have a longer "tail." Most species in the hobby-trade are hermaphrodites that have forgone the need for external fertilization, even though most recorded species are gonochoric. Some populations present a sex ratio bias that could lean either direction, with some going so far as to having 1 male for every 100 females