These monogeneans have both marine and freshwater representatives, and can be identified by their distinctive opisthaptor.
All species have a direct life cycle but a few species are capable of parthenogenetic reproduction.
The prohaptor is not well developed. The main feature is an opisthaptor consisting of multiple copies of smaller, discrete attachment structures. Each subunit is composed primarily of a sucker or a clamp, and may be pedunculate or sessile.