Myxozoans are endoparasites with complex life cycles that alternate between invertebrate and vertebrate hosts. Though considered protozoans for over 150 years, they are now recognized as metazoans, given their multicellularity and ultrastructural features. In recognition of synapomorphies and cnidarian-specific genes, myxozoans were placed recently within the phylum Cnidaria. Although they have lost genetic and structural complexity on the path to parasitism, myxozoans have retained characteristic cnidarian cnidocysts, but use them for initiating host infection. Myxozoans represent at least 20% of phylum Cnidaria, but as a result of rapid evolution, extensive diversification and host specialization, they are probably at least as diverse as their free-living relatives. The ability of myxozoans to infect freshwater, marine and terrestrial hosts implies that Cnidaria are no longer constrained to the aquatic environment.
Bibliographical noteFunding Information:
We thank Thomas Bosch for the invitation to submit this perspective paper. This research was supported by Research Grant No. IS-5001-17C from BARD, The United States-Israel Binational Agricultural Research and Development Fund and from Grant No. 47496 from USA-Israel Binational Science Foundation (BSF), Jerusalem, Israel .
© 2018 Elsevier GmbH
ASJC Scopus subject areas
- Animal Science and Zoology