GNS Science

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

New Zealand Cenozoic Mollusca

Paracomitas protransenna (Marshall & Murdoch, 1923)


(Pl. 42r): GS10849, 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 r.

Synonymy: Surcula protransenna Marshall & Murdoch 1923, p. 126; Paracomitas (Paracomitas) protransenna, Beu & Maxwell 1990, p. 327, pl. 42r.

Classification: Turridae: Cochlespirinae

Description: Small for family (13-17 mm high), tall and narrow. The only prominent sculpture is a protruding, rounded shoulder carina; a much weaker spiral cord forms a peribasal angulation on last whorl; surface on and below shoulder carina bears many close, very low, wide spiral cords; faint growth lines form the only axial sculpture. Anal sinus deep and evenly concave, occupying strongly concave sutural ramp; outer lip swings strongly forward below sinus. Canal long and narrow, straight, open, without fasciole. Protoconch of 1.5 whorls, with dome-shaped, smooth apex but tall second whorl, with prominent, narrow median keel developing after first half- whorl.

Comparison: The ancestry of Paracomitas protransenna is unknown; it is succeeded by P. gemmea (Castlecliffian; Pl. 49q) and P. augusta (Murdoch & Suter) (Recent), both of which have nodules around the shoulder carina. This is one of several taxa of Turridae that seem to have appeared abruptly in New Zealand early in Nukumaruan time.

Distribution: Nukumaruan; Waikopiro Stream, southeast of Takapau, southern central Hawke's Bay (type); widespread and not uncommon in blue-grey siltstone deposited in c. 30-60 m throughout central and southern Hawke's Bay; uncommon in southern Wairarapa. We are not aware of records from Wanganui basin, but this is a distinctive biostratigraphical index species of Nukumaruan age in Hawke's Bay.

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)


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