Home > Animals > Invertebrates > Flatworms




Category: Invertebrates



The structure of flatworms (flat) reflects their physiology – they have no body cavity other than a gut in most cases and rely on diffusion for respiration. Traditional zoology texts have divided this phylum into Turbellaria (Planarians) and three parasitic groups: Cestoda (tapeworms), Trematoda (flukes), and Monogenea (fish parasites), though scientific articles may present a more phylogenetically nuanced picture. For example, recent molecular research suggests that Turbellarians may have arisen polyphyletically (from two independent groups from different ancestral groups). Parasitic flatworms are a significant public health concern worldwide but are sometimes employed for beneficial purposes, such as controlling mosquito and invasive snail populations.




Data & Facts

Scientific Classification
Kingdom - Animalia
Phylum - Platyhelminthes
Class - Cestoda
Class - Monogenea
Class - Trematoda
Class - Turbellaria

Did you know?
Interesting Animal Facts

The world’s first Animals

Invertebrates were the first animals to evolve. While their soft bodies left precious few records behind, there are fossils of sponge-like animals that are 665 million years old, as well as traces of tracks and burros from worm-like animals going back 1 billion years. By comparison, the earliest birds appeared only 150 million years ago! And not only were invertebrates first, they are the most plentiful of animals - it is estimated that 97% of all animals living on the Earth today are invertebrates, with several groups containing more species than all vertebrates combined!

Learn more >>


NAIA - National Animal Interest Alliance Discover Animals is a web-based educational resource offered by the NAIA
To learn more about the NAIA or about other NAIA programs, visit us at www.NAIAOnline.org
if you would like to help, join or support the NAIA or any of its programs please click here >>