Figure 13 in Phylogeny of the deep-sea cirripede family Scalpellidae (Crustacea, Thoracica) based on shell capitular plate morphology

Figure 13. Carinolatera: A, B, Arcoscalpellum pedunculatum (Hoek, 1883); C, Arcoscalpellum regina (Pilsbry, 1907); D, E, Arcoscalpellum michelottianum (Seguenza, 1876); F, Arcoscalpellum quadratum (Dixon, 1850), London Clay, Eocene, Minster, Sheppey, Kent, UK (original of Withers, 1953, pl. 26, fig. 13), NHMUK In. 34504; G, H, Regioscalpellum regium (Thomson, 1873); I, J, Regioscalpellum darwini (Hoek, 1883); K, L, Diotascalpellum rubrum (Hoek, 1883); M, N, Diotascalpellum gigas (Hoek, 1883); O, P, Arcuatoscalpellum arcuatum (Darwin, 1851b), Albian, Gault Clay, Paddlesworth, Kent, NHMUK In. 61368; Q, R, Cretiscalpellum striatum (Darwin, 1851b), Campanian chalk, Norwich, UK. NHMUK IC 1198. Comparative morphology of carinolatus in out-group Cretiscalpellum and Scalpellinae to illustrate morphological variation and phylogenetic trends. Note the overall progression in morphology from the out-group (Q, R), through Arcuatoscalpellum arcuatum (P, Q), to Diotascalpellum (D. rubrum, K, L), involving differentiation of the inframedian latus surface. In the more derived R. regium (G, H), R. darwini (I, J), and R. gigas (M, N) the umbo is incurved, has migrated to a more dorsal position, and a low internal shelf has developed adjacent to the upper latus. In Arcoscalpellum (Arcoscalpellum michelottianum, D, E; Arcoscalpellum quadratum, F), the umbo is more incurved, the apex subapical, and a upper latus surface has developed (see Fig. 10 for nomenclature). Scale bars: A–I, M, N, 1 mm; K, L, O–R, 0.5 mm.