Thoracica

Thoracica is an infraclass of crustaceans which contains the most familiar species of barnacles found on rocky coasts, such as Semibalanus balanoides and Chthamalus stellatus. They have six well-developed limbs, and may be either stalked or sessile. The carapace is heavily calcified. The group includes free-living and commensal species.

Classification
This article follows Chan et al. (2021) and WoRMS in placing Thoracica as an infraclass of Thecostraca and in the following classification of thoracicans down to the level of family:


 * Infraclass Thoracica Darwin, 1854
 * Superorder Phosphatothoracica Gale, 2019
 * Order Iblomorpha Buckeridge & Newman, 2006
 * Family Iblidae Leach, 1825
 * Family Idioiblidae Buckeridge & Newman, 2006
 * Order †Eolepadomorpha Chan et al., 2021
 * Family †Eolepadidae Buckeridge, 1983
 * Family †Praelepadidae Chernyshev, 1930
 * Superorder Thoracicalcarea Gale, 2015
 * Order Balanomorpha Pilsbry, 1916
 * Superfamily Balanoidea Leach, 1817
 * Family Balanidae Leach, 1817
 * Family Pyrgomatidae Gray, 1825
 * Superfamily Chthamaloidea Darwin, 1854
 * Family Catophragmidae Utinomi, 1968
 * Family Chionelasmatidae Buckeridge, 1983
 * Family Chthamalidae Darwin, 1854
 * Family Pachylasmatidae Utinomi, 1968
 * Family Waikalasmatidae Ross & Newman, 2001
 * Superfamily Coronuloidea Leach, 1817
 * Family Austrobalanidae Newman & Ross, 1976
 * Family Bathylasmatidae Newman & Ross, 1971
 * Family Chelonibiidae Pilsbry, 1916
 * Family Coronulidae Leach, 1817
 * Family Tetraclitidae Gruvel, 1903
 * Superfamily Elminioidea Chan et al., 2021
 * Family Elminiidae Foster, 1982
 * Superfamily †Pachydiadematoidea Chan et al., 2021
 * Family †Pachydiadematidae Chan et al., 2021
 * Order Calanticomorpha Chan et al., 2021
 * Family Calanticidae Zevina, 1978
 * Family †Cretiscalpellidae Buckeridge, 1983
 * Family †Titanolepadidae Gale & Sørensen, 2015
 * Order Pollicipedomorpha Chan et al., 2021
 * Family Lithotryidae Gruvel, 1905
 * Family Pollicipedidae Leach, 1817
 * Family †Zeugmatolepadidae Newman, 1996
 * Order Scalpellomorpha Buckeridge & Newman, 2006
 * Superfamily Lepadoidea Chan et al., 2021
 * Family Heteralepadidae Nilsson-Cantell, 1921
 * Family Lepadidae Darwin, 1852
 * Family Malacolepadidae Hiro, 1937
 * Family Poecilasmatidae Annandale, 1909
 * Family Rhizolepadidae Zevina, 1980
 * Superfamily Neolepadoidea Chan et al., 2021
 * Family Neobrachylepadidae Newman & Yamaguchi, 1995
 * Family Neolepadidae Yamaguchi, Newman & Hashimoto, 2004
 * Family Neoverrucidae Newman, 1989 in Hessler & Newman, 1989
 * Family Probathylepadidae Ren & Sha, 2015
 * Superfamily Scalpelloidea Chan et al., 2021
 * Family Scalpellidae Pilsbry, 1907
 * Family †Proverrucidae Newman, 1989 in Hessler & Newman, 1989
 * Order Verrucomorpha Pilsbry, 1916
 * Family Verrucidae Darwin, 1854
 * Family †Eoverrucidae Gale, 2020
 * Order †Archaeolepadomorpha Chan et al., 2021
 * Family †Archaeolepadidae Gale, 2019
 * Family †Myolepadidae Gale, 2015 in Gale & Sørensen, 2015
 * Family †Stramentidae Withers, 1920
 * Order †Brachylepadomorpha Withers, 1923
 * Family †Brachylepadidae Woodward, 1901