Myxozoa

From Palaeos

The relationships of Myxozoa within animals are highly contentious. Okamura et al. (2002) regard the presence of muscle blocks in the basal myxozoan Buddenbrockia as support for a position within Bilateria, as shown in some molecular phylogenies where Myxozoa clusters with Nematoda. As such, Myxozoa is here listed as Ecdysozoa incertae sedis. However, it is possible that the clustering of Myxozoa and Nematoda is due to long-branch attraction, with both groups showing accelerated rates of evolution.

In other phylogenies, the Myxozoa group with Cnidaria, specifically with the parasitic hydrozoan Polypodium. This alternative is also supported by the ultrastructure of the myxozoan polar capsule, which is very similar to (and may be homologous with) the cnidarian nematocysts. A third alternative places the Myxozoa as sister to Bilateria, with the nematocyst/polar capsule character retained from the ancestor of Cnidaria + Bilateria.

<==Myxozoa
   |  i. s.: Myxosoma
   |         |--M. cerebralis
   |         `--M. morone
   |--Malacosporea
   |    |--Buddenbrockia plumatellae Schröder 1910
   |    `--Tetracapsula
   |         |--T. bryosalmonae
   |         `--T. bryozoides
   `--Myxosporea [Myxosporidia]
        |--Myxoproteus reinhardtii
        |--Sphaeromyxa
        |--Kudo cerebralis
        |--Myxidium
        |    |--M. bergense
        |    |--M. incurvatum
        |    `--M. trachinorum
        `--Ceratomyxa
             |--C. acadiensis
             |--C. macrospora
             `--C. urophysis

* Type species of genus indicated

[edit] References

Klein-MacPhee, G. 2002a. Cods. Family Gadidae. In Bigelow and Schroeder’s Fishes of the Gulf of Maine (B. B. Collette & G. Klein-MacPhee, eds.) 3rd ed. pp. 223-261. Smithsonian Institute Press: Washington.

Klein-MacPhee, G. 2002b. Pipefishes and seahorses. Family Syngnathidae. In Bigelow and Schroeder’s Fishes of the Gulf of Maine (B. B. Collette & G. Klein-MacPhee, eds.) 3rd ed. pp. 321-326. Smithsonian Institute Press: Washington.

Klein-MacPhee, G. 2002c. Temperate basses. Family Moronidae. In Bigelow and Schroeder’s Fishes of the Gulf of Maine (B. B. Collette & G. Klein-MacPhee, eds.) 3rd ed. pp. 374-389. Smithsonian Institute Press: Washington.

Klein-MacPhee, G. 2002d. Righteye flounders. Family Pleuronectidae. In Bigelow and Schroeder’s Fishes of the Gulf of Maine (B. B. Collette & G. Klein-MacPhee, eds.) 3rd ed. pp. 560-587. Smithsonian Institute Press: Washington.

Klein-MacPhee, G., & B. B. Collette. 2002. Scorpionfishes. Family Scorpaenidae. In Bigelow and Schroeder’s Fishes of the Gulf of Maine (B. B. Collette & G. Klein-MacPhee, eds.) 3rd ed. pp. 331-338. Smithsonian Institute Press: Washington.

Okamura, B., A. Curry, T. S. Wood & E. U. Canning. 2002. Ultrastructure of Buddenbrockia identifies it as a myxozoan and verifies the bilaterian origin of the Myxozoa. Parasitology 124: 215-223.

Prescott, L. M., J. P. Harley & D. A. Klein. 1996. Microbiology (3rd ed.) Wm. C. Brown Publishers: Dubuque (Iowa).

Credits

CKT061206