Barnacles
Guides
Coronulidae
Whale Barnacles
Coronulidae is a family of barnacles (Cirripedia) commonly known as whale barnacles, though their host associations extend beyond cetaceans to include sea turtles and crocodilians. Members are obligate epizoic species that attach to mobile marine hosts during their free-swimming larval stage. The family includes the genus Chelonibia, which exhibits exclusively passive feeding behavior—a unique trait among barnacles where the species relies entirely on host-generated water currents rather than facultatively switching between active and passive feeding modes.
Crustacea
crustaceans
Crustacea is a major subphylum of arthropods encompassing approximately 67,000 described species, with estimates suggesting this represents only 1-10% of actual diversity. The group includes familiar aquatic forms such as crabs, lobsters, shrimp, krill, and barnacles, as well as terrestrial representatives like woodlice. Crustaceans are united by biramous (two-parted) limbs and characteristic larval development, often involving a nauplius stage. Current phylogenetic understanding places Crustacea as paraphyletic with respect to Hexapoda (insects and allies), with both groups now combined in the clade Pancrustacea. The subphylum exhibits extraordinary morphological diversity, ranging from the 100-micrometer Stygotantulus stocki to the Japanese spider crab with a 3.8-meter leg span.
Lepadiformes
stalked barnacles, goose barnacles
Lepadiformes is an order of stalked barnacles within the class Maxillopoda. Members possess a fleshy peduncle that attaches the capitulum (shell) to substrates, distinguishing them from sessile acorn barnacles. The order includes approximately nine extant families, with Lepadidae being the most species-rich. Many species are epibiotic, attaching to mobile marine hosts including crustaceans, elasmobranchs, and marine debris.
Thecostraca
Barnacles and Allies
Thecostraca is a class of marine crustaceans encompassing over 2,200 described species, with barnacles (subclass Cirripedia) comprising the vast majority. The group includes three major lineages: sessile suspension-feeding barnacles, parasitic ascothoracidans that infect cnidarians and echinoderms, and the enigmatic Facetotecta, known only from planktonic larvae. Members undergo distinctive larval development, typically featuring a nauplius stage followed by a cypris stage that facilitates settlement. Thecostraca exhibits remarkable life history diversity, ranging from free-living suspension feeders to endoparasites with highly derived morphologies.