Neogloboquadrina pseudopachyderma (Cita, Premoli-Silva, and Rossi)

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 : 51

Neogloboquadrina pseudopachyderma (Cita, Premoli-Silva, and Rossi)

Figures 17.15-17.17

1965 Globorotalia pseudopachyderma Cita, Premoli-Silva, and Rossi , p. 233, pl. 20, figs. 3, 4, 6, pl. 31, fig. 6, p. 235, text-fig. 5.

1974 Globigerina pseudopachyderma Cita, Premoli-Silva, and Rossi — Olsson, pl. 2, figs. A—J.

1975 Neogloboquadrina atlantica (Berggren) — Poore and Berggren, pl. 1, fig. 8—13, pl. 2, fig. 7.

1985 Neogloboquadrina pachyderma (Ehrenberg) — Ibaraki, p. 138, pl. 13, figs. 3, 4.

2000 Neogloboquadrina inglei Kucera and Kennett , p. 80, pl. 1, figs. 1—13.

2003 Neogloboquadrina incompta (Cifelli) — Ujiié, p. 41, pl. 1, fig. 2 (non Globigerina incompta Cifelli, 1961 ).

2004 Neogloboquadrina incompta (Cifelli) — Hanagata, pl. 2, figs. 1, 2.

Remarks. Almost all specimens from the Pliocene of Miyakojima Island exhibit dextral coiling except for a single specimen from sample 2-2 of the Minebari Formation which is sinistral.

There have been extensive taxonomic studies of the morphological variations of N. pachyderma and related species, including N. borealis [= Globigerina bulloides d’Orbigny var. borealis Brady,

1881, first referred to as Globigerina bulloides arctic variety by Brady, 1878, p. 435, pl. 21, fig. 10; also reprinted as N. pachyderma by Jones, 1994, p. 113, pl. 114, figs. 19, 20], N. pseudopachyderma , N. incompta , N. atlantica [= Globigerina atlantica Berggren, 1972 , pp. 972, 973, pl. 1, fig. 1—7; Poore and Berggren, 1975], and N. inglei . In addition, attempts have been made to distinguish morphotypes based on wall calcification/encrustation, chamber inflation, lobulation, or test size (e.g., Kennett, 1968; Bandy, 1972; Srinivasan and Kennett, 1974; Reynolds and Thunell, 1986; Bergami et al., 2009; Eynaud et al., 2009). However, the relationship among these species is still confused. For example, it is speculated that Poore and Berggren (1975) included N. pseudopachyderma and N. incompta , and also Neogloboquadrina praehumerosa (as here understood) in their N. atlantica , as judged from their illustrations.

Among those studies, Keller (1978b) regarded incompta and puseudopachyderma as morphotypes of N. pachyderma , focusing on test size assuming the differences in test shape mirrored growing stages. Her work should be valued for treating incompta and pseudopachyderma in the discussion; later work did not even mention those species.

Recent molecular study, based on r-DNA, is expected to resolve this problem (e.g., Darling et al., 2006, 2007). So far, DNA extraction and morphological classification have not been properly combined in previous studies.

Occurrence. Dextral specimens are common in the Onogoshi and Minebari formations. A single sinistral specimen is available from the Minebari Formation.

Figures

FIGURE 17. Family Globorotaliidae and Pulleniatinidae. All scale bars = 0.1mm. 1, 2. Neogloboquadrina acostaensis (Blow), 1: MPC-25996 from sample MK01 (Yonahama Formation, PL2); 2: MPC-25997 from sample MK02B (Minebari F., PL5). 3, 4. Neogloboquadrina blowi (Rögl and Bolli), 3: MPC-25998 from sample 6 (Yonahama F., PL2); 4: MPC- 25999 from sample 6-2 (Yonahama F., Yonahama F., PL2). 5, 6. Neogloboquadrina humerosa (Takayanagi and Saito), 5: MPC-26000 from sample 15 (Yonahama F., PL3); 6: MPC-26001 from sample MK02A (Minebari F., PL5). 7—14. Neogloboquadrina incompta (Cifelli), 7: MPC-26002 from sample 14-2 (Yonahama F., PL4); 8: MPC-26003 from sample 16 (Yonahama F., PL3); 9: MPC-26004 from sample 3-2-low-silt (Onogoshi F., PL1); 10: MPC-26005 from sample 10 (Onogoshi F., PL2); 11: MPC-26006 from sample 15 (Yonahama F., PL3); 12: MPC-26007 from sample MK01 (Yonahama F., PL2); 13: MPC-26008 from sample 6-2 (Yonahama F., PL2); 14: MPC-26009 from sample 3- 2-up-sand (Onogoshi F., PL1). Specimens of 8—10, right coiling (dextral) form; 11—14, left coiling (sinistral) form. 15—17. Neogloboquadrina pseudopachyderma (Cita, Premoli-Silva, and Rossi), 15: MPC-26010 from sample 12 (Minebari F., PL5); 16: MPC-26011 from sample MK01 (Yonahama F., PL2); 17: MPC-26012 from sample 2-2 (Minebari F., PL5). 15 and 16, right coiling (dextral) form; 17, left coiling (sinistral) form. 18, 19. Neogloboquadrina praehumerosa (Natori), 18: MPC-26013 from sample MK01 (Yonahama F., PL2); 19: MPC-26014 from sample MK02B (Minebari F., PL5). 20, 21. Pulleniatina obliquiloculata (Parker and Jones), 20: MPC-26018 from sample 17 (Yonahama F., PL2); 21: MPC-26019 from sample 5 (Minebari F., PL5). 20, left coiling (sinistral) form; 21, right coiling (dextral) form.