Parafrondicularia helenae (Chapman)

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 : 28-29

Parafrondicularia helenae (Chapman)

Figures 10.19, 10.20

1941 Parafrodicularia helenae Chapman , pp. 154, 170, pl. 9, fig. 5.

1941 Plectofrondicularia interrupta (Karrer) — LeRoy (Part 1), p. 31, pl. 3, figs. 49, 50. (non Frondicularia interrupta Karrer, 1877 ).

1964 Plectofrondicularia interrupta (Karrer) — LeRoy, p. F29, pl. 5, fig. 25.

1994 Plectofrondicularia helenae (Chapman) — Jones, p. 78, pl. 66, figs. 6, 7.

Remarks. According to Jones (1994), P. interrupta is a junior synonym of the other valid species, P. helenae . Parafrondicularia japonica Asano (1938a) , type species of the genus Parafrondicularia , resembles P. helenae , but it can be differentiated by the character of the longitudinal striations that do not extend over the sutures as clearly illustrated by Aoki (1968) as Plectofrondicularia japonica (Asano) . The genus Parafrondicularia is distinguished from Plectofrondicularia in having a longer biserial juvenile stage. If we regard such a feature to fall within the range of variation of the genus Plectofrondicularia as Jones (1994) did, there is the problem of homonymy between Plectofrondicularia japonica Asano (1953) and Parafrondicularia japonica Asano (1938a) .

Occurrence. Rare in the Onogoshi and Yonahama formations.

Figures

FIGURE 10. Family Nodosariidae, Stilostomellidae, and Vaginulinidae. All scale bars = 0.1mm, unless otherwise indicated. 1, 2. Grigelis orectus Loeblich and Tappan, 1: MPC-26294, 2: MPC-26295, both from sample 3-2-low-silt (Onogoshi Formation, PL1). 3, 4. Laevidentalina advena (Cushman), 3: MPC-26334 from sample 5 (Minebari F., PL5); 4: MPC-26335 from sample MK02A-2 (Minebari F., PL5). 5. Laevidentalina antarctica (Parr), MPC-26336 from sample 8 (Yonahama F., PL4). 6, 7. Laevidentalina ariena (Patterson and Pettis), 6: MPC-26337 from sample 3-2-low-silt (Onogoshi F., PL1); 7: MPC-26338 from sample 11 (Onogoshi F.,?PL1). 8. Laevidentalina bradyensis (Dervieux), MPC- 26339 from sample 1 (Minebari F., PL5); 8.3 magnified view of aperture. 9, 10. Laevidentalina subemaciata (Parr), 9: MPC-26340 from sample 3 (Onogoshi F., PL1); 10: MPC-26341 from sample 3-2-low-silt (Onogoshi F., PL1); 10.4 magnified aperture oblique-view. 11. Laevidentalina sp.A, MPC-26342 from sample 6 (Yonahama F., PL2). 12. Mucronina hasta (Parker, Jones, and Brady), MPC-26379 from sample 8-2 (Yonahama F., PL4). 13, 14. Neugeborina longiscata (d'Orbigny), 13: MPC-26547 from sample 6-2 (Yonahama F., PL2); 14: MPC-26391 from sample MK02B (Minebari F., PL5). 15—18. Pseudonodosaria discreta (Reuss), 15: MPC-26434 from sample 2-2 (Minebari F., PL5); 16: MPC-26435 from sample MK01 (Yonahama F., PL2); 17: MPC-26436 from sample 2-2 (Minebari F., PL5); 18: MPC-26437 from sample MK02A (Minebari F., PL5); 15 and 16 megalospheric forms, 17 and 18 microspheric forms. 19, 20. Parafrondicularia helenae (Chapman), 19: MPC-26418 from sample 3-2-low-silt (Onogoshi F., PL1); 20: MPC- 26419 from sample MK01 (Yonahama F., PL2). 21, 22. Proxifrons inaequalis (Costa), 21: MPC-26428 from sample 3- 2-up-sand (Onogoshi F., PL1); 22: MPC-26429 from sample 6 (Yonahama F., PL2). 23, 24. Lenticulina aculeata (d'Orbigny), 23: MPC-26350 from sample 10 (Onogoshi F., PL1); 24: MPC-26351 from sample 18 (Oura F.,?PL1).