GNS Science

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

New Zealand Cenozoic Mollusca

Comitas latiaxialis (Marshall, 1918)


(Pl. 26n): GS7068, Q8/f9687, Pakaurangi Point, Kaipara Harbour, probably from Pakaurangi Member, Altonian (GNS, ex C.R. Laws Colln.)

Beu & Maxwell (1990): Chapter 11; p. 236; pl. 26 n.

Synonymy: Surcula latiaxialis Marshall 1918, p. 267

Classification: Turridae: "Cochlespirinae" clade 3 or 4 (Puillandre et al. 2008)

Description: Size moderate for genus (height 35-45 mm), fusiform, spire a little over half total height. Protoconch small, conical, of about 2.5 smooth whorls. Teleoconch of 9 whorls, bluntly shouldered near middle on spire, sutural ramp concave with low subsutural fold; last whorl broadly excavated, with a moderately long neck. Axial sculpture of prominent, rounded costae with broad, concave interspaces, reaching from near middle of sutural ramp to lower suture on spire, dying out on base of last whorl; 6-8 per whorl. Spiral sculpture on ramp of a narrow cord on subsutural fold, and fine threads below; rest of shell with numerous fine cords, some with interstitial threads. Aperture pyriform, rather narrow, with a moderately long, unnotched siphonal canal; columella almost straight. Inner lip weakly impressed; outer lip thin with a moderately deep U-shaped sinus on ramp.

Comparison: Comitas latiaxialis differs from other New Zealand Comitas species by its slender shape, its small, conical protoconch and its very fine spiral sculpture. A similar, unnamed species from the north shore of Parengarenga Harbour (Altonian) has a mamillate protoconch and somewhat coarser spiral sculpture. Research based on DNA of living Indo-Pacific species (Puillandre et al. 2008) has shown that there are at least 2 distinct clades assigned to Comitas, so this and similar species possibly belong in another (unnamed?) genus.

Distribution: Altonian, Pakaurangi Formation, Pakaurangi Point, Kaipara Harbour (type) (rare).

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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