Alabaminella weddellensis ( Earland, 1936 )

Setoyama, Eiichi & Kaminski, Michael A., 2015, Neogene benthic foraminifera from the southern Bering Sea (IODP Expedition 323), Palaeontologia Electronica (International ed. in English) 76 (4), pp. 1-30 : 12

Alabaminella weddellensis ( Earland, 1936)

Figure 5.3a–c

1936 Eponides weddellensis Earland : p. 57, pl. 1, figs. 65–67.

Description. Test very small, biconvex, low trochospiral, tightly coiled with five chambers in the final whorl. Umbilicus closed. Periphery subangular. Chambers elongated on the spiral side, triangular on the umbilical side, increasing in size gradually. Sutures clear, depressed, slightly curved on the spiral side, radial and straight on the umbilical side. Wall finely perforated. Aperture a basal arch near the peripheral edge, continuing as a basal slit to the umbilicus.

Remarks. The specimens in this study are also similar to Eponides (?) cf. Eponides pusillus (Parr) described by McCulloch (1977) which may actually belong to Alabaminella weddellensis .

Superfamily DISCORBINELLACEA Sigal, 1952

Family PARRELLOIDIDAE Hofker, 1956

Genus PARRELLOIDES Hofker, 1956

Parrelloides healdi ( Stewart and Stewart, 1930)

Figures 5.6a–c, 5.7a–c

1930 Eponides healdi Stewart and Stewart : p. 70, pl. 8, fig. 8.

1990 Gyroidina healdi (Stewart and Stewart) ; Finger, 118, plate-figs. 1–9.

1992 Gyroidina healdi (Stewart and Stewart) ; Finger, p. 88, pl. 36, figs. 1–6.

Description. Test of medium size, low trochospiral, tightly coiled, biconvex, circular in outline, with seven and a half to nine chambers in the final whorl and a closed umbilicus. Periphery rounded to slightly pinched. Sutures flush, slightly curved backwards on the spiral side, straight on the umbilical side. A small basal pore-like aperture with a slight lip. The aperture is placed in the middle of the apertural face between the umbilicus and periphery and does not extend to or position at the periphery.

Remarks. This form is superficially similar to Hansenisca sp. A , but differs in possessing a closed umbilicus and only one aperture and being more biconvex. It also differs from Parrelloides densus Saidova (1975) in possessing sutures that are curved backwards and the more acute periphery. The known range of this species in California is from the Oligocene to the Pliocene ( Finger, 1990).

Figures

FIGURE 5. All scale bars are 100 µm. 1. Valvulineria cf. Valvulineria sadonica, 4H-CC; a. dorsal view; b. ventral view; c. edge view. 2. juvenile form of Islandiella helenae?, 1H-CC; a. ventral view; b. dorsal view; c. edge view. 3. Alabaminella weddellensis, 13H-3, 146–148 cm; a. dorsal view; b. ventral view; c. edge view. 4. Cibicidoides mundulus, 18H- 3, 146–148 cm; a. ventral view; b. dorsal view; c. edge view. 5. Cibicidoides simplex, 1H-CC; a. ventral view; b. dorsal view; c. edge view. 6. Parrelloides healdi, 1H-CC; a. dorsal view; b. ventral side view; c. edge view showing the porelike aperture. 7. Parrelloides healdi, 25H-5, 146–148 cm; a. spiral view; b. umbilical view; c. edge view showing the pore-like aperture. 8. Epistominella pulchella, 4H-CC; a. spiral view; b. umbilical view; c. edge view showing the elongate arch aperture. 9. Laticarinina pauperata, 52H-CC. 10. Cibicidoides wuellerstorfi, 10H-3, 146–148 cm; a. ventral view; b. dorsal view; c. edge view. 11. Nonionella digitata, 9H-5, 146–148 cm; a. dorsal view; b. edge view; c. ventral side.