Expansion of the rare trochid Calliovarica ( Mollusca: Gastropoda) into eastern Zealandian waters during the late Paleocene- early Eocene thermal event

The late Paleocene-early Eocene greenhouse interval saw equator-pole sea-surface temperature gradients weaken and tropical and subtropical molluscs reach far southern waters, including eastern Zealandia, during this major thermal maximum. One of the rarest gastropods from this interval, the early Eocene chilodontine trochid gastropod Calliovarica H. Vokes, was previously recorded only from two species in California to Washington State, western North America. Described herein is a new occurrence, C. rangiaotea n. sp., from the Red Bluff Tuff of Chatham and Pitt islands, southwest Pacific, where it is rare, and recorded from volcanogenic sediments associated with Surtseyan-style volcanism. All three recorded species are characterized by a browsing/grazing, epifaunal lifestyle on volcanic, hard substrates.