Type of wall: Cancellate, spinose ruber/sacculifer-type wall texture.

Test morphology: “Test large, globular, 10 to 13 chambers arranged in three whorls, in a moderately high trochospiral, lobate, oval in outline, chambers spherical to subspherical; in spiral view 3½- 4 globular, embracing chambers in final whorl, increasing gradually in size, sutures straight or gently curved, moderately incised; in umbilical view 3½ globular chambers, increasing moderately rapidly in size, sutures depressed to incised, straight, umbilicus wide, square, deep, aperture umbilical, usually with teeth projecting into umbilicus from one or more chambers. Teeth vary from small and triangular to narrow elongate projections, often with a distinct rim or lip around the edges of the tooth that connect with the apertural lip; in edge view chambers globular in shape, embracing, teeth leaning into the umbilicus” (Pearson and Wade, 2015:18).

• Globigerina sp. aff. yeguaensis Weinzierl and Applin.—Blow and Banner, 1962, pl. XI, figs. P, Q [lower Oligocene G. oligocaenica Zone, Lindi area, Tanzania]. [Not Weinzierl and Applin, 1929.]
• Globigerina eocaena Gümbel.—Stainforth and others, 1975 (partim):268-270, fig. 115, no. 5-7 [upper Eocene Pachuta member, Yazoo Fm., Alabama]. [Not Gümbel, 1868.]
• Subbotina ? yeguaensis (Weinzierl and Applin).—Leckie and others, 1993:125, pl. 3 (partim), fig. 2 [upper Oligocene Zone O7, ODP Hole 628A, Little Bahama Bank, western North Atlantic Ocean], fig. 6 [upper Eocene Zone E16, ODP Hole 628A, Little Bahama Bank, western North Atlantic Ocean]. [Not Weinzierl and Applin, 1929.]
• Dentoglobigerina cf. globularis (Bermúdez).—Wade and others, 2007:172, pl. II, figs. a-d [upper Oligocene Zone O5, ODP Hole 1218B, equatorial Pacific Ocean]. [Not Bermúdez, 1961.]
• Subbotina sp. Pearson and Wade, 2015:16, figs. 14.1-14.3, 14.5, 14.9 [lower Oligocene Zone O1, TDP 17, Stakishari, Tanzania], figs. 14.4, 14.6 [lower Oligocene Zone O1, TDP 12, Stakishari, Tanzania], fig. 14.7 [upper Eocene Zone E15/16, TDP 12, Stakishari, Tanzania], fig. 14.8 [lower Oligocene Zone O1, TDP 11, Stakishari, Tanzania].

DISTINGUISHING FEATURES: The equatorial outline is in general diamond-shaped with chambers arranged in a cross. Subbotina projecta n. sp. is closely related to S. tecta “but is distinguished by its higher trochospiral coiling, wider, deeper, and generally more square umbilicus and detailed morphology of the teeth, which, although highly variable, can be quite elongate and are generally rimmed by a thin lip of constant thickness. It is distinguished from S. yeguaensis by its smaller size, more globular chambers, more incised umbilical sutures and by possessing true teeth rather than a broad, tapering lip” (Pearson and Wade, 2015:15). As seen in the synonymy list above, this morphotype has previously been attributed to Dentoglobigerina globularis (Bermúdez). However the SEMs of the holotype of globularis reveal a quite different general morphology, with more radially compressed and appressed chambers (see Chapter 11, this volume).

DISCUSSION: This species was referred to as “Subbotina sp. 2” in Wade and Pearson (2008). “Our specimens show clear spine holes indicating a spinose condition in life. The relatively free, loosely attached spherical chambers establish the relationship with other Subbotina species” rather than Dentoglobigerina (Pearson and Wade, 2015:16).

PHYLOGENETIC RELATIONSHIPS: Subbotina projecta n. sp. probably developed from S. tecta in the uppermost Eocene.

STRATIGRAPHIC RANGE: Subbotina projecta n. sp. appears in the upper Eocene Zone E16 (Wade and Pearson, 2008 referred to as Subbotina sp. 2) and ranges through the Oligocene. Wade and others (2007) found specimens in upper Oligocene Zone O5, and Leckie and others (1993) have recorded specimens of Subbotina ? yeguaensis that are consistent with Subbotina projecta n. sp. in the uppermost Oligocene Zone O7 at ODP Sites 628 and 803.

GEOGRAPHIC DISTRIBUTION: Probably restricted to low latitudes; currently known from the Gulf of Mexico, Indian Ocean (Tanzania), equatorial Pacific Ocean (ODP Sites 1218 and 803) and equatorial Atlantic Ocean (ODP Site 628).

STABLE ISOTOPE PALEOBIOLOGY: Multispecies stable isotope analysis from the lower Oligocene Zone O1 at Tanzania Drilling Project Site 12 indicates a positive δ18O signal consistent with a thermocline dwelling habitat (Wade and Pearson, 2008).

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