Laboratory of Animal Morphology


Hidetaka FURUYA
mail hfuruya @

Animal Science


Graduate School of Science



Research Theme

My interests are in reading the meaning of animal forms. We uses comparative anatomical approaches to understand the morphological evolution and adaptation of animals.

Biology of Dicyemid Mesozoans

We are studying how the animal form had evolved in the life history using the dicyemid mesozoans (Phylum Dicyemida), a unique group of animals that inhabit the renal organ of cephalopod mollusks. The dicyemid body consists of only 20 to 40 cells and represents the smallest number of cells in the animal kingdom. Dicyemids have neither body cavities nor differentiated organs, and were named "Mesozoa" for the dicyemids as an intermediate between Protozoa and Metazoa in body organization. However, some zoologists regard the simple organization of dicyemids to be the result of specialization of parasitism. Recently we have revealed that dicyemids are not truly primitive animals, that deserve the name of “mesozoans”, but that they belong to the metazoans. It still remains to be explored how such a simple body organization has evolved. Dicyemids are subjected to a number of selecting pressures due to their unique habitat with the renal organs of cephalopod hosts. In terms of morphological and ecological adaptation, this microenvironment could afford a space for a simple natural experiment.

0Life cycle of dicyemids.

1DAPI-stained image of a dicyemid mesozoan. Cell nuclei are brightly stained.



Graduate School of Science
Osaka University
Toyonaka, Machikaneyama 1-1
Osaka 560-0043

TEL:81-6-6850-5817 FAX:81-6-6850-5817(Dr. H. Furuya)
TEL:81-6-6850-5807 FAX:81-6-6850-5817(Dr. K. Ito)