First report on the complete mitochondrial genome of the deep-water scalpellid barnacle Arcoscalpellum epeeum (Cirripedia, Thoracica, Scalpellidae)

The evolutionary diversity of barnacles, with an updated classification of fossil and living forms

We present a comprehensive revision and synthesis of the higher-level classification of the barnacles (Crustacea: Thecostraca) to the genus level and including both extant and fossils forms. We provide estimates of the number of species in each group. Our classification scheme has been updated based on insights from recent phylogenetic studies and attempts to adjust the higher-level classifications to represent evolutionary lineages better, while documenting the evolutionary diversity of the barnacles. Except where specifically noted, recognized taxa down to family are argued to be monophyletic from molecular analysis and/or morphological data. Our resulting classification divides the Thecostraca into the subclasses Facetotecta, Ascothoracida and Cirripedia. The whole class now contains 14 orders, 65 families and 367 genera. We estimate that barnacles consist of 2116 species. The taxonomy is accompanied by a discussion of major morphological events in barnacle evolution and justifications for the various rearrangements we propose.

Complete mitochondrial genome of the hydrothermal vent stalked barnacle Vulcanolepas fijiensis (Cirripedia, Scalpelliforms, Eolepadidae)

The family Eolepadidae is the only stalked barnacle in hydrothermal vent regions. Here, we determined the mitogenome of the eolepadid Vulcanolepas fijiensis. The mitogenome was 17,374 bp long, with 76.6% AT content. Its protein-coding gene organization was identical to that of the deep-sea scalpellid Arcoscalpellum epeeum. On the mitogenomic tree, two scalpellomorphan families (Eolepadidae and Scalpellidae) were monophyletic while the other scalpellomorphan family Pollicipedidae did not form the monophyletic group with them. Further mitogenomic analysis of undetermined taxa in hydrothermal vents is required to deepen our understanding of their phylogenetic relationships.