棘皮動物プルテウス幼生の収斂進化について

抄録

Two types of larval morphology are recognized in extant echinoderms, namely auricularia-type larvae for starfish, sea cucumbers and sea lilies, and pluteus-type larvae for sea urchins and brittle stars. Since sister-grouping of the sea urchins and the sea cucumbers is supported by both fossil evidence and molecular data, the pluteus-type larvae are regarded to have evolved convergently in the sea urchins and the brittle stars. This paper briefly reviews recent progress in our work on comparative molecular developmental studies in the echinoderms. We investigated expressions and function of developmental genes, which are essential for sea urchin larval skeletogenesis, in the starfish and brittle stars. Based on expression data, we infer how the larval skeleton evolved in the sea urchins and brittle stars.