Dentalina sp. A

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 : 26

Dentalina sp. A

Figure 9.19

Description. Test elongate and very slightly curved; large for the genus, up to 3.4 mm in length, 0.4 mm in diameter; chambers not inflated, almost of similar width and length, enlarging slowly as added; sutures slightly depressed; wall finely perforated; numerous longitudinal striations transverse to sutures; aperture terminal, circular, radiating slits obscured due to poor preservation.

Remarks. This form resembles Dentalina flintii (Cushman) (e.g., Jones 1994, p. 76, pl. 64, figs. 20—22) and Nodosaria spirostriolata Cushman (1917) , but chambers are less inflated than in the former, and the test is slightly more curved than the latter.

Occurrence. A single partly broken specimen from the Yonahama Formation.

Figures

FIGURE 9. Family Hauerinidae and Nodosariidae. All scale bars = 0.1mm, unless otherwise indicated. 1. Pyrgo subsphaerica (d'Orbigny), MPC-26087 from sample 6-2 (Yonahama Formation, PL2). 2. Pyrgo simplex (d'Orbigny), MPC-26086 from sample MK02B (Minebari F., PL5). 3. Triloculina tricarinata Parker, Jones, and Brady (young form), MPC-26104 from sample 1 (Minebari F., PL5). 4. Sigmoilina cf. sigmoidea (Brady), MPC-26097 from sample 6 (Yonahama F., PL2), aperture broken. 5, 6. Spirosigmoilina tenuis (Cžjžek), 5: MPC-26100 from sample 11 (Onogoshi F.,?PL1); 6: MPC-26101 from sample 18 (Oura F., PL1). 7, 8. Spirosigmoilina pusilla (Earland), 7: MPC-26102 from sample 5-2 (Minebari F., PL5); 8: MPC-26103 from sample 11 (Onogoshi F.,?PL1). 9, 10. Sigmoilopsis schlumbergeri (Silvestri), 9: MPC-26098 from sample 18 (Oura F.,?PL1); 10: MPC-26099 from sample MK01 (Yonahama F., PL2). 11. Chrysalogonium equisetiformis (Schwager), MPC-26196 from sample 16 (Yonahama F., PL3). 12, 13. Dentalina albatrossi (Cushman), 12: MPC-26216, 13: MPC-26217, both from sample 2-2 (Minebari F., PL5). 14. Chrysalogonium deceptorium (Schwager), MPC-26195 from sample 2-2 (Minebari F., PL5). 15, 16. Dentalina aff. catenulata (Brady), 15: MPC-26218 from sample 6-2 (Yonahama F., PL2); 16: MPC-26219 from sample 11 (Onogoshi F.,?PL1). 17, 18. Dentalina mutsui Hada, 17: MPC-26220 from sample 18 (Oura F.,?PL1); 18: MPC-26221 from sample MK01 (Yonahama F., PL2). 19. Dentalina sp.A, MPC-26222 from sample 8-2 (Yonahama F., PL4).