Bolivina cochei Cushman and Adams

Hanagata, S & Nobuhara, T, 2015, Illustrated guide to Pliocene foraminifera from Miyakojima, Ryukyu Island Arc, with comments on biostratigraph, Palaeontologia Electronica (Cambridge, England) 33 (8), pp. 1-142 : 68

Bolivina cochei Cushman and Adams

Figures 22.17, 22.18

1935 Bolivina cochei Cushman and Adams , p. 19, pl. 3, figs. 6, 7.

Remarks. This species resembles Bolivina robusta in test size and general shape, but is distinguished by its compressed test with acute and thinly carinated periphery. Revets (1996a) suggested that this species belonged to the genus Brizalina , not Bolivina . It also resembles Bolivina marginata Cushman (1918) in possessing a peripheral keel, but that form has a more slender test.

Occurrence. Abundant in a single sample of the Yonahama Formation.

Figures

FIGURE 22. Family Bolivinidae. All scale bars = 0.1mm. 1, 2. Bolivina antiqua d'Orbigny, 1: MPC-26140, 2: MPC- 26141, both from sample 18 (Oura Formation,?PL1). 3—6. Bolivina cacozela Vella, 3: MPC-26142 from sample 2-2 (Minebari F., PL5); 4: MPC-26143 from sample 5 (Minebari F., PL5); 5: MPC-26144 from sample 10 (Onogoshi F., PL2); 6: MPC-26145 from sample 16 (Yonahama F., PL3). Specimens of 3 and 4 have larger test size than those of 5 and 6. 7, 8. Bolivina glutinata Egger, 7: MPC-26148 from sample 15 (Yonahama F., PL3); 8: MPC-26149 from sample 16 (Yonahama F., PL3). 9, 10. Bolivina retia Oki, 9: MPC-26154, 10: MPC-26545, both from sample 4 (Minebari F., PL5); 9.4, moisturized specimen showing internal septa. 11, 12. Bolivina robusta Brady, 11: MPC-26155 from sample 5 (Minebari F., PL5); 12: MPC-26156 from sample 10 (Onogoshi F., PL2). 13, 14. Bolivina striatula Cushman, 13: MPC-26157 from sample 14-2 (Yonahama F., PL4); 14: MPC-26158 from sample MK01 (Yonahama F., PL2). 15, 16. Bolivina variabilis (Williamson), 15: MPC-26161 from sample 16 (Yonahama F., PL3); 16: MPC-26162 from sample MK01 (Yonahama F., PL2). 17, 18. Bolivina cochei Cushman and Adams, 17: MPC-26146, 18: MPC-26147, both from sample MK01 (Yonahama F., PL2). 19, 20. Bolivina kiiensis Asano, 19: MPC-26150 from sample 3 (Onogoshi F., PL1); 20: MPC-26151 from sample 3-2-low-silt (Onogoshi F., PL1). 21, 22. Bolivina pacifica Cushman and McCulloch, 21: MPC-26152 from sample 1-2 (Minebari F., PL5); 22: MPC-26153 from sample MK01 (Yonahama F., PL2). 23. Bolivina cf. subspinescens Cushman, MPC-26159 from sample MK01 (Yonahama F., PL2). 24. Bolivina cf. yabei Takayanagi, MPC-26163 from sample MK01 (Yonahama F., PL2). 25, 26. Bolivina sp.A, 25: MPC-26164 from sample 11 (Onogoshi F.,?PL1); 26: MPC-26165 from sample 16 (Yonahama F., PL3). 27. Bolivina translucens Phleger and Parker, MPC-26160 from sample 5-2 (Minebari F., PL5).