Cibicidoides pachyderma (Rzehak)

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 : 99-100

Cibicidoides pachyderma (Rzehak)

Figures 30.1-30.4

1886 Truncatulina pachyderma Rzehak , p. 87, pl. 1, fig. 5.

1964 Cibicides pseudoungerianus (Cushman) — LeRoy, p. F45, pl. 8, figs. 13—15 (?non Truncatulina pseudoungeriana Cushman, 1922c ).

1986 Cibicidoides pachyderma (Rzehak) — Morkhoven, Berggren, and Edwards, p. 68, pl. 22, fig. 1.

1988 Cibicides pseudoungerianus (Cushman) — Wang, Zhang, Zhao, Min, Bian, Zheng, Cheng, and Chen, p. 162, pl. 25, figs. 15, 16.

1989 Cibicides pseudoungerianus (Cushman) — Ōki, p. 151, pl. 21, fig. 5.

1992 Cibicidoides pachyderma (Rzehak) — Hatta and Ujiié (b), p. 187, pl. 35, fig. 5.

1994 Cibicidoides pachyderma (Rzehak) — Jones, p. 98, pl. 94, fig. 9.

1995 Cibicidoides pachyderma (Rzehak) — Ujiié, p. 67, pl. 9, fig. 5.

Remarks. This is one of the more familiar species in bathyal waters around southern Japanese Islands. It has bioconvex or umbilically more convex test, moderate test size for the genus, about nine to eleven chambers in final whorl, coarsely pitted spiral side, and moderately curved sutures. Hatta and Ujiié (1992b) suggested that it had been recorded previously as Cibicidoides pseudoungerianus (Cushman) . Two aberrant forms that have inflated chambers are also illustrated here. Wang and Lutze (1986) noted several inflated varieties occasionally seen in calcareous hyaline taxa including Cibicidoides , and this is one of them.

Occurrence. Common in the Onogoshi, Yonahama, and Minebari formations.

Figures

FIGURE 30. Family Parrelloididae, Pseudoparrellidae, Discorbinellidae, and Planulinidae. All scale bars = 0.1mm. 1—4. Cibicidoides pachyderma (Rzehak), 1: MPC-26203 from sample MK01 (Yonahama Formation, PL2); 2: MPC- 26204 from sample 4-2 (Minebari F., PL5); 3: MPC-26205 from sample 3-2-up-sand (Onogoshi F., PL1); 4: MPC- 26206 from sample 5-2 (Minebari F., PL5); 3 and 4, inflate-chamber variation. 5, 6. Cibicidoides sp.A, 5: MPC-26207, 6: MPC-26208, both from sample MK01 (Yonahama F., PL2). 7, 8. Parrelloides bradyi (Trauth), 7: MPC-26409 from sample 7 (Yonahama F., PL4); 8: MPC-26410 from sample MK01 (Yonahama F., PL2). 9, 10. Alabaminoides exiguus (Brady), 9: MPC-26108 from sample MK01 (Yonahama F., PL2); 10: MPC-26109 from sample MK02A (Minebari F., PL5). 11, 12. Eilohedra rotunda (Husezima and Maruhasi), 11: MPC-26230 from sample 1-2 (Minebari F., PL5); 12: MPC-26231 from sample MK02B (Minebari F., PL5). 13, 14. Facetocochlea pulchra (Cushman), 13: MPC-26255 from sample 3-2-low-silt (Onogoshi F., PL1); 14: MPC-26256 from sample 5-2 (Minebari F., PL5). 15. Discorbinella montereyensis Cushman and Martin, MPC-26223 from sample 12 (Minebari F., PL5). 16, 17. Laticarinina pauperata (Parker and Jones), 16: MPC-26348 from sample 7 (Yonahama F., PL4); 17: MPC-26349 from sample MK01 (Yonahama F., PL2). 18—21. Hyalinea balthica (Schröter), 18: MPC-26328 from sample MK01 (Yonahama F., PL2); 19: MPC-26329 from sample MK02B (Minebari F., PL5); 20: MPC-26330 from sample 5 (Minebari F., PL5); 21: MPC- 26331 from sample 5-2 (Minebari F., PL5); 20 and 21, inflated-chamber variation.