Bryozoans from the late Cretaceous Kahuitara Tuff of the Chatham Islands, New Zealand

Abstract

Taylor, P.D., & Gordon, D.P., December, 2007. Bryozoans from the Late Cretaceous Kahuitara Tuff of the Chatham Islands, New Zealand. Alcheringa 31, 339-363. ISSN 0311-5518.

Fourteen bryozoan species are described from the Campanian – Maastrichtian Kahuitara Tuff of Pitt Island, substantially increasing the known diversity in this deposit from the two species recorded previously and making it the most diverse bryozoan biota yet described from the Cretaceous of Australasia. Nine of the Kahuitara Tuff bryozoans are cyclostomes, four are cheilostomes, and one is a shell-boring ctenostome. Seven new species are described: Ceriocava hakepaensis sp. nov., Tholopora australis sp. nov., Crisidmonea lanauzeorum sp. nov., Cookobryozoon cretacea sp. nov., Chiplonkarina preeceorum sp. nov. Chiplonkarina bifoliata sp. nov. and Aechmella rangiauriensis sp. nov. The remaining species are left in open nomenclature because of preservational deficiencies or lack of taxon-diagnostic gonozooids. The ctenostome family Cookobryozoidae is subsumed in the Terebriporidae. The new family Chiplonkarinidae is proposed for anascan cheilostomes previously assigned to the paraphyletic Electridae and distinguished by having primarily erect colonies with long, tubular zooids reminiscent of stenolaemates. None of the Kahuitara Tuff bryozoan species is known elsewhere, but all apart from one genus occur in roughly coeval deposits. No families regarded as particularly characteristic of the austral post-Cretaceous are evident. The relatively large number (three) of co-occurring species of Chiplonkarina is notable, as is the dominance of cyclostomes and the first record of Tholopora in the Southern Hemisphere.

Paul D. Taylor [[email protected]], Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, UK; Dennis P. Gordon [[email protected]], National Institute of Water and Atmospheric Research, Private Bag 14-901, Kilbirnie, Wellington, New Zealand; received 7.3.2006, revised 3.9.2006.

Key words:

• Cretaceous
• Kahuitara Tuff
• Chatham Islands
• New Zealand
• systematics
• Bryozoa
• Cyclostomata
• Ctenostomata
• Cheilostomata
• new species
• palaeobiogeography

Acknowledgements

We are grateful to Dr Hamish J. Campbell (IGNS) for guidance in the field, and to him and Dr David MacKinnon (University of Canterbury) for help in collecting during the 1999 field season. The various families of Pitt Islanders are thanked for welcoming us to their island. Tony Wighton (NHM) prepared the thin-sections.