The Halocyprida is one of the two orders within the Myodocopa, in turn a subclass of the ostracods. Like their relatives in the order Myodocopida, they have a long exopod on the second antenna.
The Halocyprida and their Myodocopida relatives both belong to the Myodocopa subclass of ostracods. They exhibit a similar feature where they have a long exopod on the second antenna.