GNS Science

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

New Zealand Cenozoic Mollusca

Aethocola (Aethocola) affiliata (Finlay, 1926)


(Pl. 15d): GS9516, I40/f6675, Trig Z, Otiake, Waitaki Valley, Waitakian (GNS)

Beu & Maxwell (1990): Chapter 10; p. 159; pl. 15 d.

Synonymy: Austrofusus affiliatus Finlay, 1926b, p. 238; Austrofusus (Austrofusus) affiliatus, Beu & Maxwell 1990, p. 159, pl. 15d.

Classification: Buccinulidae

Description: Rather small for genus (height 27-37 mm), bucciniform, spire 0.5 total height. Protoconch conical, of about 4 whorls with opisthocyrt costae on last half whorl, otherwise smooth. Teleoconch of 6-6.5 whorls, first whorl convex, later whorls bluntly to sharply shouldered at 0.5-0.6 whorl height on spire, sutural ramp steep, sides sub- vertical or sloping inwards; last whorl with prominent peribasal angulation, contracted below to moderately long, twisted neck. Axial sculpture of prominent, rounded costae with somewhat broader interspaces, reaching from suture to suture on earliest whorls, but obsolete on upper part of base of last whorl, and in some shells becoming less distinct and more crowded near outer lip; 11-14 costae on penultimate whorl. Spiral sculpture of narrow, low, well-spaced cords, typically with interstitial threads, 3 cords on base typically considerably stronger than other spirals. Cords on angulations distinctly tubercular where they cross axial costae, other cords only slightly thickened or unaffected. Aperture ovate, columella concave above, strongly twisted to left below, forming a moderately long, slightly curved, notched siphonal canal; fasciole rounded, of variable development, much more prominent in some shells than in others. Outer lip with numerous fine lirae extending well within aperture, lirae developing at a very early stage of growth (height 14 mm).

Comparison: Aethocola affiliata is distinguished from other species of Aethocola (sensu stricto) by its relatively small size and moderately fine spiral sculpture, by the development of rather prickly tubercles on the crests of the axial costae, and by having outer lip lirae developing at an unusually early stage of growth. A. acuticostata (Pl. 6m) seems to be the most closely related species, differing in having much finer spiral sculpture.

Distribution: Waitakian; Otekaike Limestone, Trig Z, Otiake (type); Campbell Park School, Otekaike; Brother's Stream and Sister's Creek, Hakataramea Valley; Mount Harris Formation, upper Tengawai River; Chatton Formation, Mataura River, near Brydone, Southland. Uncommon at Brydone, but common at other localities.

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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