E-Fauna BC Home

Eupentacta quinquesemita is stiff to the touch due to abundant calcareous ossicles in the skin and tube feet. The body grows to 5 to 10 cm in length. The non-retractile tube feet give it a spiny look. It has five rows of tube feet (four tube feet in width) with smooth skin between. The two ventral tentacles are smaller than the other eight. This character is useful for identifying this species when only the tentacles are visible. The expanded tentacles are creamy white with tinges of yellow or pink at the bases.

Skin ossicles: numerous large, porous, ovoid bodies dominate the ossicles but among them are small, delicate baskets. These latter are important in differentiating this species from Eupentacta pseudoquinquesemita.

Similar Species

Eupentacta quinquesemita is almost identical in external appearance to E. pseudoqinqesemita. The differences are subtle, and separation of these two species can only be determined with certainty by analysis of the skin ossicles. E. pseudoquinqesemita has softer, non-retractile tube feet, up to 10 across each row. In British Columbia and Washington this species is subtidal and often found in sediment. They often have small pieces of shell and other debris attached to their tube feet. If only the tentacles are visible, E. quinquesemita can also be confused with the white tentacles of Cucumaria pallida. However, C. pallida has 10 equal-sized tentacles, not 8 equal and 2 small. Pentamera trachyplaca and P. lissoplaca are also similar in general appearance but the ossicles are clearly distinct.