Robbea judithae

Robbea judithae , R. lotti and R. weberae

The corpus of all three species exhibits strongly lobulated nuclei fitting in between myofilaments ( Figs. 5b–d View Fig and 10c, d View Fig ). In the isthmus, their shapes vary from ovoid to spherical in the anterior part, distinctly elongated in the centre and ranging from ovoid to slightly elongated in the posterior part ( Figs. 7b–d View Fig , 8a, b, e View Fig and 9a–c View Fig ). The nuclei in the bulbus are spherical to ovoid and are located at the distal margin in R. judithae ( Figs. 7b View Fig and 13b View Fig ), at the distal margin and close to the bulbus lumen in R. lotti ( Figs. 7c View Fig , 9a View Fig and 13c View Fig ) and are regularly distributed in R. weberae ( Figs. 7d View Fig and 13d View Fig ).

Cyathorobbea hypermnestra , Cy. ruetzleri and Cy. agricola

Nuclei of the corpus are ovoid to slightly elongated and lobulated in both Cy. hypermnestra and Cy. ruetzleri to fit in between myofilaments and the dorsal ampulla ( Figs. 4e, f, 5h View Fig and 10b View Fig ). Cy. agricola has elongated nuclei in the corpus that show a peculiar zigzag pattern ( Fig. 4g). In the isthmus and posterior bulbus, nuclei are ovoid to spherical in both Cy. hypermnestra and Cy. ruetzleri ( Figs. 5i View Fig , 7e, f View Fig and 13e, f View Fig ). In the isthmus of Cy. agricola , their shape ranges from ovoid to elongated. The latter nuclei are roughly four times longer than wide ( Figs. 7g View Fig and 11e View Fig ). Some individuals lack nuclei in the posterior-most isthmus due to its slenderness. In both Cy. hypermnestra and Cy. ruetzleri , one spherically shaped nucleus in the dorsal sector of the bulbus is slightly larger than the others ( Figs. 11b View Fig and 13f View Fig ), whereas the ovoid nuclei in the bulbus of Cy. agricola are roughly of equal size ( Figs. 7g View Fig , 11e View Fig and 13g View Fig ).