CAMPANULARIIDAE, Johnston, 1836

FAMILY CAMPANULARIIDAE View in CoL

T h e P CA w i t h a l l s p e c i e s s h o w s t h a t s e v e r a l measurements of length and diameter ( LH, DHMa, DHMe, DHB, LP, TLT; for all abbreviations, see Table 1) are responsible for the largest amount of variation in the data (PC1), while the presence of cusps ( NC, HCMax, HCMin) and perisarc thickness (PPMe, PHMe, PSS) explain another direction of high variation among species (PC2; Fig. 1A, B View Figure 1 ; Table 1). Differences in size separate Bonneviella ingens Nutting, 1915 , B. regia ( Nutting, 1901) , B. superba Nutting, 1915 and Tulpa tulipifera ( Allman, 1888) from other Campanulariidae , based on their larger hydrothecae and pedicels ( Fig. 1A, C View Figure 1 ). Similarly, Rhizocaulus verticillatus ( Linnaeus, 1758) can be distinguished from Campanularia and Orthopyxis by its larger hydrothecae and trophosome ( Fig. 1D, E View Figure 1 ). Differences in size are not only informative for delimiting different genera, but are considerably variable among Bonneviella species (Supporting Information, Table S2). The dimensions of the specimens of B. regia ( USNM 1106181; Govindarajan et al., 2006) are congruent with the type material of this species, while measurements of the unidentified specimens ( Bonneviella sp.2 and sp.4; Govindarajan et al., 2006) are closer to type material of the other species examined (Supporting Information, Table S2). Bonneviella sp.2 ( USNM 1106182), here re-identified as B. superba , and B. grandis ( Allman, 1876) are among the species with larger hydrothecae and trophosome, while Bonneviella sp.4 ( USNM 1106187), here re-identified as B. ingens , have hydrothecae and trophosome almost half the size of the three previous species (Supporting Information, Table S2; Fig. 2A–C View Figure 2 ).

Perisarc thickness, as well as the number and height of hydrothecal cusps, separate several species within Campanulariidae ( Fig. 1B View Figure 1 ). Silicularia rosea Meyen, 1834 is clearly distinct from Bonneviella , Campanularia , R. verticillatus and Tulpa due to its thicker perisarc ( Figs 1C View Figure 1 , 2D View Figure 2 ). In contrast, species of Campanularia can hardly be differentiated by any of the characters included in the analysis, because they have similar morphological patterns ( Fig. 1D View Figure 1 ). The exception is C. hincksii Alder, 1856 , slightly set apart from the remaining Campanularia by its taller hydrothecal cusps (HCMax, HCMin; Fig. 1D View Figure 1 ), a character that shows little or no overlap among the species when intraspecific variation is considered ( Fig. 3B View Figure 3 ). However, the remaining characters do not show this pattern ( Fig. 3A, C, D View Figure 3 ).

Perisarc thickness is also informative for separating Orthopyxis from species of Campanularia , although morphological variation may attenuate this difference. Several specimens of O. sargassicola and O. crenata ( Hartlaub, 1901) group together with Campanularia , because of their thinner perisarc and presence of hydrothecal cusps, compared to the remaining species of Orthopyxis ( Fig. 1E View Figure 1 ; Supporting Information, Fig. S1C View Figure 1 ). Although O. crenata and O. sargassicola have a thicker perisarc on average,