Phylogeny of the deep‐sea cirripede family S calpellidae ( C rustacea, T horacica) based on shell capitular plate morphology

A cladistic analysis of 23 extant species of the deep‐sea pedunculate cirripede family S calpellidae was undertaken, based on 61 shell plate characters, and taking the J urassic– C retaceous scalpellomorph genus C retiscalpellum as an out‐group. The consensus tree shows progressive morphological change from basal to more derived taxa, but a derived group is marked by major morphological innovation, including 27 character state changes that permit subdivision of the family into two sharply demarcated clades – the more basal group is here placed within a redefined S calpellinae ( A rcoscalpellum , Arcuatoscalpellum  gen. nov. , Diotascalpellum  gen. nov. , G raviscalpellum , Regioscalpellum  gen. nov. , and S calpellum ), and a more derived group named A migdoscalpellinae subfam. nov. that shows numerous progressive trends in morphology, permitting the recognition of three genera ( A migdoscalpellum , C atherinum , and W eltnerium ). The phylogeny is independently supported by a recently published multiple DNA marker‐based molecular phylogeny. The more basal S calpellinae appeared in the A ptian ( E arly C retaceous, 120 Mya), and derived A migdoscalpellinae were already present by the C ampanian ( L ate C retaceous, 78 Mya), represented by Catherinum anglicum  sp. nov. and A migdoscalpellum bellulum from the UK C halk. Specialized receptacles to accommodate dwarf males in the apical interior of the scutum evolved at least three times during the history of the scalpellids. © 2015 The Linnean Society of London