Recognition and distribution of HeterianBelemnopsisin south-west Auckland

Abstract

Belemnopsis annae, Belemnopsis maccrawi, and Belemnopsis keari are characteristic taxa of the Heterian stratotype at Kawhia Harbour, New Zealand. When morphological criteria are used, their recognition elsewhere can be difficult. Contrasts in body form are slight, and when collections consist of fragmentary specimens or of juveniles there is a strong possibility of misidentification. Statistical procedures based on apical line positions and on cross sectional shape provide a simple method of recognition. Supporting stratigraphic evidence is available. The succession of taxa present in the Heterian stratotype can be recognised in the Port Waikato region, and two of them are shown to be widely distributed in south–west Auckland.