Pannychia

Pannychia is a genus of sea cucumber belonging to the family Laetmogonidae. These animals live on the ocean floor, favoring areas with soft sediment, and are found at depths ranging from 212 to 2,598 meters. In the North Pacific Ocean, they are a dominant presence in their ecosystem.

Members of this genus have a mouth located on the underside of the body, without any surrounding papillae, though many slender papillae are scattered across the rest of the body. They possess 16 to 20 non-retractile tentacles with finger-like discs. Their ossicles, or internal skeletal pieces, are prominent and mostly wheel-shaped, though two species—P. henrici and P. virgulifera—also have ossicles described as "arched rods." The wheel ossicles come in both larger and smaller forms. The tube feet vary in size.

Pannychia can be told apart from all other Elasipodida by two shared features: dorsal papillae on the ventro-lateral ambulacra and large wheel ossicles with teeth on the brim. It differs from other Laetmogonids by having tube feet on the mid-ventral radius, and from Laetmogone by having shorter papillae. In life, species range from white to dark violet, with some appearing light yellow or pale brown.

Seven species are currently recognized: Pannychia fecundum, P. henrici, P. moseleyi, P. nagasakimaruae, P. rinkaimaruae, P. taylorae, and P. virgulifera. Historically, seven species and subspecies were lumped into P. moseleyi, but a 2022 study reinstated P. henrici and P. virgulifera as valid names. A phylogenetic analysis based on mitochondrial COI gene sequences supports these relationships.