Taxonomic study of the kinorhyncha in Japan. III. Echinoderes sensibilis n. sp. (Kinorhyncha: Cyclorhagida) from Tanabe Bay.

A new species of echinoderid kinorhynch, Echinoderes sensibilis, is described and illustrated using light and electron microscopy. The specimens were collected from masses of the red algae Corallina pilulifera growing in intertidal pools in Tanabe Bay, Honshu Island, Japan. Diagnostic characters of E. sensibilis include the presence of middorsal spines on segments 6-10; lateral spines/tubules on segments 4, 7-12; remarkable trapezium-like subventral fields of minute cuticular hairs on segments 5-12. The positions of numerous sensory spots, large sieve areas, glandular tubes and the shape of terminal tergal and sternal extensions are also diagnostic. All taxonomic characters used for this description are illustrated by SEM. Echinoderes sensibilis constitutes the fifty-eight valid species of the genus Echinoderes and the fourteenth species described from the Pacific Ocean. This is the third representative of Pacific kinorhynchs found only in the intertidal zone and the first Pacific Echinoderes living on red macroalgae in intertidal pools.