Lenticulina depressa (Asano)

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 : 30

Lenticulina depressa (Asano)

Figures 11.3, 11.4

1938 Robulus depressus Asano (a), p. 202, pl. 25, fig. 15, pl. 26, figs. 10, 27, pl. 28, fig. 11.

1956 Robulus depressus Asano — Asano (a), p. 50, pl. 1, figs. 12—14, pl. 2, figs. 11, 12, pl. 3, figs. 1, 2, pl. 6, figs. 34, 36.

Diagnosis. Moderate- to large–sized species with significantly depressed, almost parallel-sided test, thin, well-developed peripheral keel, biumbilicate.

Remarks. Specimens of the present study exhibit fewer chambers averaging six to seven in final whorl; originally nine to eleven chambers were recorded. We interpret this as variation.

Occurrence. Sporadic in all formations of the present study.

Figures

FIGURE 11. Family Vaginulinidae. All scale bars = 0.1mm, unless otherwise indicated. 1, 2. Lenticulina cultrata (de Montfort), 1: MPC-26352 from sample 2 (Minebari Formation, PL5); 2: MPC-26353 from sample MK02A-2 (Minebari F., PL5). 3, 4. Lenticulina depressa (Asano), 3: MPC-26354 from sample 11 (Onogoshi F.,?PL1); last three chambers show aberrant inflation; 4: MPC-26355 from sample 18 (Oura F.,?PL1) broken specimen. 5, 6. Lenticulina inornata (d'Orbigny), 5: MPC-26356 from sample 3-2-up-sand (Onogoshi F., PL1); 6: MPC-26357 from sample MK02B (Minebari F., PL5). 7. Lenticulina iota (Cushman), MPC-26358 from sample 3-2-up-sand (Onogoshi F., PL1). 8, 9. Lenticulina orbicularis (d'Orbigny), 8: MPC-26359 from sample 6 (Yonahama F., PL2); 9: MPC-26360 from sample MK01 (Yonahama F., PL2). 10, 11. Lenticulina sintikuensis Nakamura, 10: MPC-26361, 11: MPC-26362, both from sample 6-2 (Yonahama F., PL2). 12. Lenticulina thalmanni (Hessland), MPC-26363 from sample 2-2 (Minebari F., PL5). 13, 14. Lenticulina vortex (Fichtel and Moll), 13: MPC-26364 from sample 2-2 (Minebari F., PL5); 14: MPC-26365 from sample MK02A-2 (Minebari F., PL5); 13, broken specimen. 15. Marginulinopsis striatulus (Cushman), MPC-26369 from sample 4 (Minebari F., PL5). 16, 17. Neolenticulina variabilis (Reuss), 16: MPC-26389 from sample 1-2 (Minebari F., PL5); 17: MPC-26390 from sample 18 (Oura F.,?PL1).