Figure 8. Typical Trilobatus quadrilobatus and intergradation with Trilobatus sacculifer. A–K in Systematic taxonomy of the Trilobatus sacculifer plexus and descendant Globigerinoidesella fistulosa (planktonic foraminifera)

Figure 8. Typical Trilobatus quadrilobatus and intergradation with Trilobatus sacculifer. A–K, Trilobatus quadrilobatus (d'Orbigny, 1846); L–P, Trilobatus sacculifer (Brady, 1877). A, B, E, F, G–K, ODP Site 871, Limalok Guyot, Marshall Islands, equatorial Pacific 3H/03/60–62 cm (A, E–I, K, umbilical view; B, detail of wall texture, including spine holes, infilled pores, broadened interpore ridges; J, detail of wall texture and imperforate lip developed on primary aperture); C, D, GLOW-3, south-west Indian Ocean (C, umbilical view; D, spiral view). L–P, ODP Site 871, Limalok Guyot, Marshall Islands, equatorial Pacific 3H/03/60–62 cm (L–P, umbilical view; for L note slight chamber flattening compared with I–K). Scale bars = 100 Lm, except for close-up images B and J, where scale bars = 20 Lm.