Origin and phylogeny of the Cretaceous thoracican cirripede family Stramentidae

A cladistic analysis of basal scalpellomorph cirripedes was undertaken in order to identify the phylogenetic position of the Stramentidae. This yielded a well-supported tree, in which the family is positioned crownwards of <i>Archaeolepas</i>, but basal to the families Scalpellidae and Zeugmatolepadidae. A new genus, <i>Loriolepas</i>, is described to accommodate some species previously referred to <i>Archaeolepas.</i> Basal scalpellomorphs display a remarkable change in shell mineralogy from calcium phosphate to calcium carbonate (<i>Eolepas</i> to <i>Archaeolepas</i>); the latter group is identified as a monophyletic clade, the Thoracicalcarea nov. A revised taxonomy of the predominantly Late Cretaceous cirripede family Stramentidae is presented. Stramentidae are subdivided into two subfamilies, Loriculinae subfam. nov., and Stramentinae, based on characters of tergum, carinolatus and peduncular plates. The former subfamily includes <i>Loriculina</i> Dames, 1885, <i>Metaloriculina</i> gen. nov. and, doubtfully, <i>Blastolepas</i> Drushchits &amp; Zevina, 1969, and three new species are described, <i>Loriculina ifrimae</i> sp. nov<i>.</i>, <i>Metaloriculina stramentioides</i> sp. nov and <i>Metaloriculina norvicensis</i> sp. nov. The Stramentinae include <i>Leweslepas</i> gen. nov., <i>Stramentum</i> Logan, 1897 and <i>Parastramentum</i> gen. nov. New species are <i>Leweslepas hattini</i> sp. nov, <i>L. hauschkei</i> sp. nov, <i>L. wrightorum</i> sp. nov, <i>Parastramentum albertaensis</i> sp. nov, <i>P. brydonei</i> sp. nov, <i>P. peakei</i> sp. nov, <i>Stramentum alekseevi</i> sp. nov and <i>S. praecursor</i> sp. nov<i>.</i> Cladistic analysis of the Stramentidae, based on 25 characters, supports the monophyly of the family, but relationships between subfamilies and genera are poorly resolved. However, in north-west Europe there is an evolutionary morphocline, stratigraphically calibrated, from the early Cenomanian <i>Leweslepas hauschkei</i> gen. et sp. nov. through the middle Cenomanian <i>Stramentum praecursor</i> sp. nov. to the late Cenomanian–Turonian <i>S. pulchellum</i>. A split from this lineage is found in the Western Interior Basin of North America, and the early Turonian <i>S. canadensis</i> gave rise to the middle Turonian <i>S. elegans</i>, which lived epibenthically. <i>Stramentum elegans</i> gave rise to <i>Parastramentum</i> gen. nov. http://zoobank.org/urn:lsid:zoobank.org:pub:E01B7F39-6C1B-4AF3-B79A-E2D5972D3E28