| Research Abstract |
Character analysis for the morphology of celleporids larvae distinguished six taxonomically important characters as follows: 1)corona, 2)pallial epithelium, 3)oral epithelium, 4)metasomal sac, 5)pyriform organ, and 6)messenchyme. Among them, three stable characters, pallial and oral epithelium and metasomal sac, were examined in the seven species of celleporids from Hokkaido. The polarity of the three characters transformed among the celleporids revealed that Pseudocelleporina was derived from the species of Celleporina. Among the species in Celleporina, however, the transformation series of the three characters did not coincide with each other. An out-group comparison was then applied to determine which character reflected a true phylogeny of the celleporids. Since the closest relative of celleporids has not been specified, three genera, Cellepora, Galeopsis, and Lagenipora were tentatively chosen as the out-groups. Three cladograms obtained did not agree with each other. In the present study, I was not able to get any answer to the question which cladogram involved a true phylogram, because there was no data to show which one of the three genera was the out-group of celleporids. As a result, present study anyhow accomplished the character analysis of celleporid larvae, but resulted neither cladograms nor phylograms of the species from Hokkaido. For cladistic systematics of a taxon without any appropriate out-group, a method other than the out-group comparison is needed to determine the polarity of a transformation series of characters.
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