Scalpellum

Scalpellum is a genus of stalked barnacles in the family Scalpellidae. Like other stalked barnacles, Scalpellum species attach to substrates with a flexible peduncle and display a calcified capitulum at the end, housing the feeding appendages when the animal is retracted. The genus comprises several described species with a worldwide distribution in temperate and tropical seas, often found in subtidal to shallow-water habitats on a variety of substrates, including echinoderms, mollusks, corals, and macroalgae.

Morphology and identification: Adults are pedunculated; the capitulum contains the protective calcareous plates and the aperture through which the cirri extend to feed. Species are differentiated by stalk length, plate morphology and arrangement, and details of soft tissues and appendages, typically assessed from collected specimens.

Life cycle and ecology: Scalpellum species reproduce sexually, with nauplius and cypris larval stages typical of Cirripedia, followed by settlement and development into a stalked, sessile adult. They are filter feeders, catching plankton with their cirri. Many Scalpellum individuals are epizoic or commensal on larger invertebrates such as echinoderms; others anchor directly to solid substrates. The fossil record of Scalpellidae extends back to the Mesozoic, reflecting a long evolutionary history.

Taxonomy and name: The genus name Scalpellum derives from Latin scalpellus, meaning scalpel, a reference to the sharp-edged capitulum. The World Register of Marine Species and other taxonomic databases provide current species lists and nomenclatural details.