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

Abstract

STILWELL, J.D., 2014. Expansion of the rare trochid Calliovarica (Mollusca: Gastropoda) into eastern Zealandian waters during the late Paleocene–early Eocene thermal event. Alcheringa 38. ISSN 0311–5518.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.Jeffrey D. Stilwell [Jeffrey.Stilwell@sci.monash.edu.au], School of Geosciences, Monash University, Clayton VIC 3800, Australia, and Australian Museum, 6 College Street, Sydney NSW 2000, Australia. Received 9.8.2013, revised 14.10.2013, accepted 25.10.2013.