GNS Science

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

New Zealand Cenozoic Mollusca

Exilia dalli Suter, 1907


(Pl. 21e): GS11154, J39/f26, Pareora River, foot of Mt Horrible, South Canterbury, Otaian (GNS)

Beu & Maxwell (1990): Chapter 11; p. 195; pl. 21 e.

Synonymy: Exilia dalli Suter 1907a, p. 209; Zexilia dalli

Classification: Turbinellidae

Description: Size moderate for genus (height 15-20 mm), narrowly fusiform, spire half total height. Protoconch mamillate, of about 2 whorls with weak axial costellae on last quarter whorl or so, otherwise smooth. Teleoconch of 7-8 whorls, those on spire weakly concave on adapical half, convex below; last whorl with long, slender, straight neck. Axial sculpture of narrow, opisthocline, opisthocyrt costae with somewhat wider interspaces, reaching from suture to suture on spire whorls, scarcely extending onto base of last whorl, and becoming obsolete on last whorl on some shells; 15-19 costae per whorl. Spiral sculpture absent from first whorl or so on spire, rest of shell with numerous narrow, rounded or flat- topped cords. Aperture pyriform with a long, narrow, open siphonal canal; columella almost straight or distinctly twisted. Inner lip smooth, outer lip thin, slightly flexuous.

Comparison: Exilia dalli is smaller than E. waihaoensis (Pl. 8s) and differs in having a mamillate protoconch of only two whorls rather than a dome-shaped one of three whorls.

Distribution: Waitakian-Otaian; "White Rock, Pareora River" (type — almost certainly not from the Southburn Sand at White Rock River (Altonian), but from the Mount Harris Formation at Pareora River, foot of Mt Horrible (Otaian), where it is common); Bluecliffs, Otaio River; Otekaike Limestone, Trig Z, Otiake; Campbell Park School, Otekaike; Brother's Stream, Hakataramea Valley.

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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