Miocene casuarinacean fossils from Southland and Central Otago, New Zealand

Abstract

Abundant undistorted specimens of casuarinacean “cones” (infructescences) assignable to the genus Casuarina L. ex Adan occur in Duntroonian to Waitakian (Late Oligocene to Early Miocene) quartz arenite at Landslip Hill, near Gore, Southland.. Some aspects of “cone” morphology suggest affinity with Gymnostoma L. A. S. Johnson, 1980. Casuarinacean stems and compressed “cones” also occur in comparative abundance in thin-bedded siltstones of the Manuherikia Group (Early to Mid-Miocene) at several localities near Bannockburn, Central Otago. They are not conspecific with those from Landslip Hill and probably belong to a different genus. Casuarina stellata sp. nov. from Landslip Hill and Casuarina avenacea sp. nov. from Bannockburn are described. The “cones” show the existence of a casuarinacean (sheoak) forest or scrub element in the Mid-Tertiary vegetation of Southland and Central Otago. They confirm a long-held notion, based on pollen evidence. that Casuarinaceae lived in New Zealand in Tertiary times. The presence of probable Gymnostoma is interesting. The genus is mainly tropical at the present-day with most species being found in New Caledonia and Papua New Guinea.