Plate P1. All specimens are at the same scale. 1. Thalassiosira bipora Shiono (Sample 183-1138A-8R-5, 100-101 cm). 2, 3. Actinocyclus ingens var. ovalis Gersonde (Sample 183-1138A-15R-CC). 4. Thalassiosira insigna (Jousé) Harwood and Maruyama (Sample 183-1138A-8R-CC). 5. Thalassiosira sp. 1 (this study). Arrow denotes position of prominent strutted process located between valve center and margin (Sample 183-1138A-7R-1, 100-101 cm). 6. Thalassiosira sp. cf. T. eccentrica (Ehrenberg) Cleve (high and low focus) (Sample 183-1138A-15R-CC). 7, 12. Actinocyclus ingens var. 1 (this study) (Sample 183-1138A-23R-CC). 8, 9. Actinocyclus ingens var. 2 (this study) (Sample 183-1138A-4R-1, 25-26 cm). 10. Azpeitia harwoodii Bohaty and Shiono n. sp. (Sample 183-1138A-11R-CC). 11. Actinocyclus dimorphus (Castracane) Harwood and Maruyama (Sample 183-1138A-8R-CC).

Plate P1. All specimens are at the same scale. 1. Thalassiosira bipora Shiono (Sample 183-1138A-8R-5, 100-101 cm). 2, 3. Actinocyclus ingens var. ovalis Gersonde (Sample 183-1138A-15R-CC). 4. Thalassiosira insigna (Jousé) Harwood and Maruyama (Sample 183-1138A-8R-CC). 5. Thalassiosira sp. 1 (this study). Arrow denotes position of prominent strutted process located between valve center and margin (Sample 183-1138A-7R-1, 100-101 cm). 6. Thalassiosira sp. cf. T. eccentrica (Ehrenberg) Cleve (high and low focus) (Sample 183-1138A-15R-CC). 7, 12. Actinocyclus ingens var. 1 (this study) (Sample 183-1138A-23R-CC). 8, 9. Actinocyclus ingens var. 2 (this study) (Sample 183-1138A-4R-1, 25-26 cm). 10. Azpeitia harwoodii Bohaty and Shiono n. sp. (Sample 183-1138A-11R-CC). 11. Actinocyclus dimorphus (Castracane) Harwood and Maruyama (Sample 183-1138A-8R-CC).