ABSTRACT
Cidaroid sea urchin remains (isolated radioles and rare plates) are described from marine strata of the Harnetts Formation (New Zealand Waitakian Stage (=Late Chattian – Early Aquitarian)), part of the Otaua Group (Late Oligocene – Early Miocene) outcropping in the Waimamaku Valley, in the South Hokianga district, Northland, New Zealand. Abundant large and robust spines (radioles), assigned here to two previously known Indo-Pacific genera Stereocidaris and Phyllacanthus, form part of a distinctive, transported shallow shelf component of a macrofossil assemblage occurring in grit horizons within the deep marine (bathyal) sandstone sequence. Cidaroid spine morphology allows for tentative identification of fossil taxa to species level. Several test fragments, namely large but worn interambulacral plates, have also been collected from the type locality and a possible nearby outlier of Harnetts Formation. These outcrops are locally significant as the only known exposures of the geographically restricted unit, incorporated into the Northland Allochthon during its emplacement.
Acknowledgments
The first author wishes to acknowledge the input of Jack Grant-Mackie who unfortunately passed away during the late stages of this work. His sons Ewan and Bryn gave access to his notes. Bruce Hayward alerted the first author to the Poka Road locality. Diane Yanakopulos has been an invaluable assistant in the field. Neville Hudson gave access to view collections at the University of Auckland including specimens collected by Jack and C.C. Leitch during 1964-1966. Reviews of the manuscript by Bruce, Neville and an anonymous reviewer were greatly appreciated. Eric Scott kindly donated a copy of Fell (Citation1954).
Disclosure statement
No potential conflict of interest was reported by the author(s).
Data availability statement
The data that support the findings of this study are openly available in Figshare at https://doi.org/10.6084/m9.figshare.14821872.v1