Species included: IS: L. globocarinata (Cushman 1938) (Plate 5, Figures 1–3) and FDS: L. lazarusi – new species (Plate 5, Figures 4–10, Plate 6, Figures 1–11).

Diagnosis: Directional lineage with globular–chambered tests, ahelicid in the IS and holohelicid in the FDS and periapertural structures consisting of symmetrically developed metaflanges.

Description: Test ahelicid in IS and holohelicid in FDS; the adult portion of the test consists of chambers alternately added with respect to the test growth axis. Chambers are globular, overlap at various rates and gradually increase in size. Sutures are distinct and  depressed  throughout.  Test  symmetrical  in  edge  view, with broad and simple periphery; earlier test portion is slightly compressed in the IS and distinctly compressed in the FDS. Aperture is a medium high and wide arch at the base of the last– formed chamber; it is bordered by two symmetrically developed subtriangular and narrow metaflanges, one on each test side. Chamber ornamentation consists of more or less continuous leptocostae with a width of 0.0029–0.0054 mm; a pustulose periapertural area consisting of dome–like pustules occurs in the chamber anterior portion. Test wall is calcitic, hyaline, simple and perforate; pores are circular in shape and with a diameter of 0.0010–0.0023 mm.

Remarks: Directional lineage Lazarusina develops holohelicid tests in the FDS; test compression increases along the lineage and ranges from discrete in the IS to evident in the FDS. There is a slight increase in pore size from the IS (0.0010–0.0017 mm) to FDS (0.0013–0.0023). Lazarusina differs from Spiroplecta mainly by having globular chambers with a broadly rounded periphery rather laterally pinched last–formed chambers in the IS and occasionally in the FDS, ahelicid rather than hysterohelicid test in the IS, ornamentation consisting of wider (0.0029–0.0054 mm rather than 0.0022–0.0036 mm) and more continuous leptocostae and larger pores (0.0010–0.0023 mm rather than 0.0007–0.0013 mm). Apparently the two lineages have different origins and timing of evolution: Spiroplecta initiated its evolution in the late Santonian from Planoheterohelix, whereas Lazarusina evolved in the early Campanian from the globular– chambered “G.” reussi.

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