Cretaceous bryozoans from the Chatham Islands, New Zealand

Abstract

Two bryozoan species have been found in the Kahuitara Tuff (Piripauan-Haumurian Stages; equivalent to Campanian-Maastrichtian) of Pitt Island, in the Chatham Islands, about 900 km east of the South Island of New Zealand. Cretaceous bryozoans are rare in Australasia, and the two species in this paper are the first to be formally described from New Zealand. Both species have thick dendroid colonies but whereas Ceriocava maculata sp. nov. is an unequivocal cerioporine cyclostome, the other species — Chiplonkarina campbelli sp. nov. — is more problematical and is interpreted as an aberrant ‘malacostegan’ cheilostome. Like previously described species of Chiplonkarina, C. campbelli has interzooidal walls with a central crenulated layer, indicating the former presence of an intercalary cuticle of the type found in many cheilostomes but unknown in cyclostomes. The anomalous global biogeographical distribution of bryozoans during the Cretaceous is briefly discussed.

Keywords:

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