Mesozoa (Dicyemids)


The dicyemid mesozoans are unique multicellular animals found in the kidneys of benthic cephalopod molluscs. Their life cycle is complex, but the body organization is the simplest among multicellular animals.

Keywords: cephalopod; dicyemid; host‐specificity; kidney; Mesozoa; parasite

Figure 1.

Life cycle and morphology of the dicyemid mesozoan. The upper and lower boxes represent processes in the renal sac of cephalopods and in the sea, respectively. The dashed line indicates an unknown process that probably involves the infection of a new cephalopod and the dicyemid's development into adult forms. L and H represent low and high density of individuals in the renal sac, respectively.


Further Reading

Beneden E van (1876) Recherches sur les Dicyémides, survivants actuels d’un embranchement des Mésozories. Bulletins de l’Academie Royal de Belgique 42: 3–111.

Furuya H (1999) Fourteen new species of dicyemid mesozoans from six Japanese cephalopods, with comments on host specificity. Species Diversity 4: 257–319.

Furuya H and Tsuneki K (2003) Biology of dicyemid mesozoan. Zoological Science 20: 519–532.

Furuya H; Tsuneki K and Koshida Y (1996) The cell lineages of two types of embryo and a hermaphroditic gonad in dicyemid mesozoans. Development Growth and Differentiation 38: 453–463.

Furuya H; Tsuneki K and Koshida Y (1997) Fine structure of a dicyemid mesozoan, Dicyema acuticephalum, with special reference to cell junctions. Journal of Morphology 231: 297–305.

Hochberg FG (1990) Diseases caused by protistans and mesozoans. Kinne O (ed.) Diseases of Marine Animals, vol. 3, pp. 47–202. Hamburg, Germany: Biologische Anstalt Helgoland.

Hori H and Osawa S (1987) Origin and evolution of organisms as deduced from 5S ribosomal RNA sequences. Molecular Biology and Evolution 4: 445–472.

Horvath P (1997) Dicyemid mesozoans. In: Gilbert SF and Raunio AM (eds) Embryology, Constructing the Organism, pp. 31–38. Sunderland, MA: Sinauer Associates.

Hyman LH (1940) The Invertebrates, vol. I: Protozoa through Ctenophora. New York: McGraw‐Hill.

Hyman LH (1959) The Invertebrates, vol. V: Smaller Coelomate Groups. New York: McGraw‐Hill.

Katayama T, Wada H, Furuya H, Sato N and Yamamoto M (1995) Phylogenetic position of the dicyemid Mesozoa inferred from 18S rDNA sequences. Biological Bulletin 189: 81–90.

Kobayashi M, Furuya H and Holland PWH (1999) Dicyemids are higher animals. Nature 401: 762.

Lapan A and Morowitz HJ (1975) The Dicyemid Mesozoa as an integrated system for morphogenetic studies. Journal of Experimental Zoology 193: 147–160.

McConnaughey BH (1949) Mesozoa of the Family Dicyemidae from California. University of California Publications in Zoology 55: 1–34.

McConnaughey BH (1963) The Mesozoa. Dougherty EC (ed.) The Lower Metazoa, pp. 151–165. Berkeley, CA: University of California Press.

McConnaughey BH (1983) Mesozoa. In: Adiyodi KG and Adiyodi RG, (eds) Reproductive Biology of Invertebrates, vol. 1: Oviposition and Oosorption, pp. 135–145. New York: John Wiley.

Nouvel H (1947) Les Dicyémides. 1re partie: systématique, générations, vermiformes, infusorigène et sexualité. Archives de Biologie, Paris 58: 59–220.

Short RB (1991) Marine Flora and Fauna of the Eastern United States – Dicyemida. NOAA Technical Report NMFS 100: 1–16.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Furuya, Hidetaka(Sep 2005) Mesozoa (Dicyemids). In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0004173]