Redescription of type specimens of Globorotalia chapmani Parr from the Upper Paleocene, Western Australia

Environmental scanning electron microscopy of the type specimens of Globorotalia chapmani Parr confirms that the holotype has 11 chambers, with four fully exposed on the involute umbilical side; a marginal imperforate band at least on early chambers in the final whorl; and depressed sutures between all chambers. The periphery of the final chamber is more broadly rounded than in most topotypic specimens of the species. The aperture is an extraumbilical arch highest toward the periphery, bordered above by a prominent lip, but partially obscured by extraneous material. Topotypes have four to five chambers exposed on the umbilical side, consistent marginal imperforate bands, consistent broad apertural lips, consistent microperforations, and variable fine granulate ornament scattered on the test surface.The type stratigraphic level of G. chapmani in the lower part of the Kings Park Shale contains a foraminiferal assemblage dominated by benthonic rotaliid foraminifera and interpreted to reflect a mid-neritic (50-100 m water depth) depositional environment. Few planktonic species occur in the type assemblage; these include Acarinina aquiensis (Loeblich and Tappan), Subbotina spp., and very rare Morozovella convexa (Subbotina) which together suggest a late Paleocene age (probably zone P4).