When it comes to differentiation of the sexes, nematode species usually keep it simple, dividing into hermaphrodites and males. But Auanema sp. also has worms of the female sex. Furthermore, they have other interesting sex characteristics, as the researchers note "the arrangement of genital papillae in Auanema sp. males is unique in the genus."
I am particularly intrigued because, as a xenobiologist, I have observed that multiple sexes tend to cluster in certain contexts: when evolution first starts frobbing around to make a huge variety of new organisms, and when an environment is so hard to live in that creative solutions are required. Two sexes are all you need to mix genes, and you can even do it with one if that's a hermaphrodite or the species only makes one gamete type that all go together. But in extreme conditions, certain other tricks become very useful. Males and females expend a bit less energy than hermaphrodites, but hermaphrodites can mate with anything: both handy options in a hellhole. A neuter workforce, as in social insects, can be very productive. If you're really lucky, you get a sex that can filter out bad mutations or toxins. Haven't seen that yet ... but if I were studying those worms, I'd check. It pops up in hermaphrodites sometimes. Anyhow, the newly discovered worms are tripling up in a harsh environment, so they're right on the mark. \o/
Take that, binary bigots! The universe is, quite literally, QUEERER than you can imagine. LOL