Bolivinita quadrilaterais a long-ranging species of relatively stable morphology that intermittently inhabited the New Zealand region and developed locally abundant populations in the upper Miocene (Tongaporutuan Stage), lower Pliocene (Opoitian and Waipipian Stages), and about the Pliocene-Pleistocene boundary (Mangapanian and Nukumaruan Stages). Many of the occurrences are from deep-water (outer “shelf” to bathyal) biotopes, and bathymetry may have been a major control over its stratigraphic distribution. Populations previously distinguished asB. granttayloriare considered to be conspecific withB. quadrilatera. Although spiral profiles inB. quadrilateraare mainly quasi-rectangular, a few are rhomboidal as inB.cf.pohana. There is some evidence in support of a morphocline between these taxa, but population distributions in Tongaporutuan strata suggest that they were distinct, although occupying comparable biotopes. The localised distribution ofB. quadrilatera, even in favourable, deep-water biotopes is a restriction on its use as a criterion for the base of Tongaporutuan Stage.