SPAIN, D.D.; SCOTT, C.; Dominican University of California; Dominican University of California: A Preliminary Investigation into the Ossicle Density of the Body Wall of Sea Cucumbers (CLASS: HOLOTHUROIDEA)

The body wall tissue of sea cucumbers is characterized as mutable collagenous tissue (MCT), capable of rapid, reversible changes in its mechanical properties. These changes include remarkable stiffening and softening of either the entire animal or localized portions of the body wall. Embedded within the MCT are microscopic skeletal elements called ossicles. Although ossicles play an important role in support, movement, locomotion, and protection, the quantity of ossicles, and how this quantity affects the mechanical properties of MCT, has not been explicitly studied. The focus of this investigation is to quantify the amount of ossicles present in the body wall tissue of several species of holothuroids. Sections of tissue were dried and weighed, then decalcified to remove the ossicles. The decalcified tissue was then dried and the resulting weight loss was calculated. Results from a pair of epifaunal and infaunal dendrochirotids from Family Cucumariidae indicate little variation in the relative amount of ossification. Ultimately, the amount of ossification could potentially have significant implications for the mechanical properties of mutable collagenous tissues in the body wall and their rate of change.