Paleocene isocrinids (Echinodermata: Crinoidea) from the Kauru Formation, South Island, New Zealand

Abstract

Crinoids are reported from the New Zealand Paleocene for the first time and include rare articulated columnals and brachia with pinnules. These specimens of Metacrinus sp. (Isocrinidae) are present in basal, fossiliferous, coarse-grained, quartzose sediments of the Kauru Formation, a few centimeters above schist basement, in the Kakanui Valley, North Otago. The crinoid-bearing facies probably represents earliest onlap or a storm surge onto a wave cut platform; sedimentological and paleontological evidence indicates a moderate- to high-energy environment. The crinoids were most probably buried rapidly while alive or shortly after death. The presence of isocrinids in the Kauru Formation and younger Paleogene strata reveals that the supposed shift of some isocrinids from a shallower to a deeper environment actually occurred much later in the Paleogene, and not the Late Cretaceous as previously supposed. Associated molluscs indicate a mid to upper “Wangaloan” Stage (local), equivalent to mid Paleocene. A summary of the New Zealand crinoid fossil record is presented.