Pleurostomella alternans Schwager, 1866

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 : 91

Pleurostomella alternans Schwager

Figures 27.26-27.28

1866 Pleurostomella alternans Schwager , p. 238, fig. 79.

1911 Pleurostomella alternans Schwager — Cushman, p. 50, fig. 81.

1941 Pleurostomella alternans Schwager — LeRoy (Part 1), p. 38, pl. 3, figs. 54, 55; LeRoy (Part 2), p. 82, pl. 2, figs. 12, 13.

1964 Pleurostomella alternans Schwager — LeRoy, p. F36, pl. 5, fig. 5.

1968 Pleurostomella alternans Schwager — Huang, p. 59, pl. 12, fig. 4.

1994 Pleurostomella alternans Schwager — Loeblich and Tappan, p. 133, pl. 261, figs. 13, 14.

1998 Pleurostomella alternans Schwager — Hess, p. 86, pl. 11, fig. 10.

2002 Pleurostomella alternans Schwager — Hayward, p. 302, pl. 2, figs. 22—24.

2012 Pleurostomella alternans Schwager — Hayward, Kawagata, Sabaa, Grenfell, Kerckhoven, Johnson, and Thomas, p. 228, pl. 36, figs. 10—15.

Remarks. Small form (up to 0.5 mm in length) and large forms (ca. 1.1 mm) are distinguished in samples from the Yonahama Formation. This gap in test size is large; forms might be distinguished as separate species.

Occurrence. Rare in the Yonahama and Minebari formations.

Figures

FIGURE 27. Family Uvigerinidae, Reussellidae, Fursenkoinidae, and Pleurostomellidae. All scale bars = 0.1mm. 1, 2. Euuvigerina vadescens (Cushman), 1: MPC-26247 from sample 10 (Onogoshi Formation, PL2); 2: MPC-26248 from sample 11 (Onogoshi F.,?PL1). 3—5. Uvigerina flintii Cushman, 3: MPC-26519 from sample 2-2 (Minebari F., PL5); 4: MPC-26520 from sample 3 (Onogoshi F., PL1); 5: MPC-26521 from sample 17 (Yonahama F., PL2). 6, 7. Uvigerina peregrina Cushman, 6: MPC-26522 from sample 6 (Yonahama F., PL2); 7: MPC-26523 from sample 6-2 (Yonahama F., PL2). 8. Uvigerina schencki Asano, MPC-26524 from sample 2 (Minebari F., PL5). 9. Uvigerina schwageri Brady, MPC-26525 from sample 5-2 (Minebari F., PL5). 10, 11. Angulogerina angulosa (Williamson), 10: MPC-26125 from sample MK01 (Yonahama F., PL2); 11: MPC-26126 from sample MK02B (Minebari F., PL5). 12, 13. Trifarina bradyi Cushman, 12: MPC-26517 from sample 3-2-up-sand (Onogoshi F., PL1); 13: MPC-26518 from sample 8 (Yonahama F., PL4). 14, 15. Reussella pulchra Cushman, 14: MPC-26461 from sample 2 (Minebari F., PL5); 15: MPC-26462 from sample MK01 (Yonahama F., PL2). 16. Fursenkoina acuta (d'Orbigny), MPC-26274 from sample 4-2 (Minebari F., PL5). 17—19. Neocassidulina hadai (Uchio), 17: MPC-26384 from sample 1 (Minebari F., PL5); 18: MPC-26385 from sample 15 (Yonahama F., PL3); 19: MPC-26386 from sample 16 (Yonahama F., PL3). 20, 21. Rutherfordoides mexicanus (Cushman), 20: MPC-26472 from sample 4 (Minebari F., PL5); 21: MPC-26473 from sample 5 (Minebari F., PL5). 22, 23. Rutherfordoides virgus (Nomura), 22: MPC-26474 from sample 1 (Minebari F., PL5); 23: MPC-26475 from sample 3-2-low-silt (Onogoshi F., PL1). 24, 25. Pleurostomella acuminata Cushman, 24: MPC-26420 from sample 7 (Yonahama F., PL4); 25: MPC-26421 from sample 17 (Yonahama F., PL2). 26—28. Pleurostomella alternans Schwager, 26: MPC-26422 from sample 7 (Yonahama F., PL4); 27: MPC-26423 and 28: MPC-26424 from sample 8-2 (Yonahama F., PL4); 27 large variation.