Aspidogastrids [Aspidogastrea]
Description
The Aspidogastrids, or Aspidogastrea, are a small order of flukes that are characterized by a large ventral sucker, known as the aspidogastrean sucker, which is divided into rows of small alveoli. They are primarily parasites of molluscs and some vertebrates and are distinguished by their unique attachment organ. Unlike other trematodes, members of this order have a relatively simple life cycle with no alternation of generations. They are found in both freshwater and marine environments, with marine species typically infesting bottom-dwelling hosts.