Melonis pacificum (Cushman)

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 : 110

Melonis pacificum (Cushman)

Figures 32.10, 32.11

1924 Nonionina umbilicatula (Montagu) var. pacifica Cushman , p. 48, pl. 16, fig. 3.

1933 Nonion pacificum (Cushman) — Cushman(c), p. 44, pl. 10, fig. 9.

1950 Nonion pacificum (Cushman) — Asano (part 1), p. 3, text-figs. 13, 14.

Remarks. This species is characterized by almost non-limbate sutures and inflated chambers. As Ujiié (1990) mentioned the similarity to Melonis barleeanus , chamber inflation and lack of limbation might be a variety of that species, comparable to what has been observed for Hyalinea balthica or Cibicidoides pachyderma in the present study. We retain this nomenclature here, but stress that it should be examined further.

Occurrence. Sporadic in all the formations of the present study.

Figures

FIGURE 32. Family Nonionidae, Chilostomellidae, Alabaminidae, Osangulariidae, and Oridorsalidae. All scale bars = 0.1mm. 1. Astrononion hayamaense Kurihara, MPC-26136 from sample 18 (Oura Formation,?PL1). 2. Astrononion stelligerum (d'Orbigny), MPC-26137 from sample MK01 (Yonahama F., PL2). 3, 4. Fijinonion fijiensis (Cushman and Edwards), 3: MPC-26259, 4: MPC-26260, both from sample 2-2 (Minebari F., PL5). 5. Laminononion tumidum (Cushman and Edwards), MPC-26345 from sample 15 (Yonahama F., PL3). 6, 7. Pacinonion umbilicatulum (Uchio), 6: MPC-26401 from sample 1 (Minebari F., PL5); 7: MPC-26402 from sample 12 (Minebari F., PL5). 8, 9. Melonis barleeanum (Williamson), 8: MPC-26370 from sample MK01 (Yonahama F., PL2); 9: MPC-26371 from sample MK02 (Minebari F., PL5). 10, 11. Melonis pacificum (Cushman), 10: MPC-26372 from sample 5-2 (Minebari F., PL5); 11: MPC- 26373 from sample MK02B (Minebari F., PL5). 12—14. Melonis pompilioides (Fichtel and Moll), 12: MPC-26374 from sample 3 (Onogoshi F., PL1); 13: MPC-26375 from sample 3-2-up-sand (Onogoshi F., PL1); 14: MPC-26376 from sample MK01 (Yonahama F., PL2). 15, 16. Pullenia bulloides (d'Orbigny), 15: MPC-26443 from sample 6 (Yonahama F., PL2); 16: MPC-26442 from sample MK01 (Yonahama F., PL2). 17, 18. Pullenia quinqueloba (Reuss), 17: MPC- 26444 from sample 1 (Minebari F., PL5); 18: MPC-26445 from sample 7 (Yonahama F., PL4). 19. Chilostomella cushmani Chapman, MPC-26194 from sample 5 (Minebari F., PL5). 20. Alabamina japonica (Asano), MPC-26107 from sample 12 (Minebari F., PL5). 21, 22. Osangularia culter (Parker and Jones), 21: MPC-26399 from sample 7 (Yonahama F., PL4); 22: MPC-26400 from sample 16 (Yonahama F., PL3). 23, 24. Oridorsalis umbonatus (Reuss), 23: MPC-26396 from sample 1-2 (Minebari F., PL5); 24: MPC-26397 from sample MK01 (Yonahama F., PL2).