Final answer:
Sea stars have an endoskeleton made up of small calcareous 'bones' called ossicles, which are produced by dermal cells in their dermal brachiae. These ossicles are part of the sea stars' unique support structure, allowing for functions such as movement and respiration.
Step-by-step explanation:
Yes, sea stars do have ossicles in their dermal brachiae. Ossicles are small calcareous 'bones' that make up the endoskeleton of echinoderms, including sea stars. These ossicles are produced by dermal cells, which also endow sea stars with vivid colors through pigmentation. The dermal brachiae, or papulae, function as gills and extend through the endoskeleton, which consists of these ossicles covered by an epidermis.
In sea stars, the ossicles may be fused together or embedded separately in the connective tissue of the dermis. This structure is significant for the unique morphology and anatomy of echinoderms, which exhibit pentaradial symmetry and possess a true endoskeleton, unlike the exoskeleton of arthropods. Moreover, these ossicles contribute to the support and protection of the sea stars' internal organs and play a role in their ability to move and catch prey.