GNS Science

Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)

New Zealand Cenozoic Mollusca

Splendrillia aequistriata (Hutton, 1886)


(Pl. 42t): GS 10849, V20/f8572, Devil's Elbow mudstone, top of north face of Devil's Elbow hill, Napier-Wairoa highway, Nukumaruan (GNS)

Beu & Maxwell (1990): Chapter 15; p. 327; pl. 42 t.

Synonymy: Drillia aequistriata Hutton 1886a, p. 334; Drillia (Crassispira) aequistriata; Splendrillia (Splendrillia) aequistriata, Beu & Maxwell 1990, p. 327, pl. 42t.

Classification: Drilliidae

Description: Large for New Zealand members of the genus (23-26 mm high), fusiform, with tall spire but relatively short, open anterior canal, lacking fasciole. A narrow, vertical subsutural zone is followed (downwards) by narrow, markedly concave sutural ramp, gently rounded shoulder formed by low nodules on tops of axial costae, and moderately convex whorl sides that taper gradually to canal. Almost entire surface crowded with narrow spiral cords, but over the shoulder cords are only half the width and height of those lower down. Axial costae evenly rounded, moderately prominent, 11-14 on last whorl, becoming short shoulder nodules over last half-whorl of some large specimens. Moderately deep, relatively wide anal sinus occupies whole sutural ramp, and is constricted by large parietal tubercle at top of inner lip. Protoconch dome-shaped, of 1.5 smooth whorls.

Comparison: Splendrillia aequistriata is markedly larger, a little wider, and with more prominent axial costae and more of the surface bearing spiral cords than all other New Zealand species of Splendrillia, and (except for its relatively weak subsutural fold) closely resembles the typical Australian modern species of Splendrillia.

Distribution: Nukumaruan; "Petane", i.e., hillside north of Petane Pa, north of mouth of Esk River, north of Napier (type); widespread and common in blue-grey siltstone in central and southern Hawke's Bay; rare in Wanganui basin. Largest and most common in Devil's Elbow mudstone around Devil's Elbow and the Arapaoanui Valley, north of Napier.

Cite this publication as: "A.G. Beu and J.I. Raine (2009). Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990). GNS Science miscellaneous series no. 27."
© GNS Science, 2009
ISBN 978-0-478-19705-1
ISSN 1177-2441
(Included with a PDF facsimile file copy of New Zealand Geological Survey Paleontological Bulletin 58 in CD version from: Publications Officer, GNS Science, P.O. Box 30368 Lower Hutt, New Zealand)


Back to index page