Conus armoricus
(Suter, 1917)
Shell rather small, biconic, with a low,
conoidal, gradated spire and elongated tapering body-whorl. Sculpture : The
spire-whorls have well-pronounced arched growth-lines which descend vertically
over the body-whorl, the base of which is adorned with about 12 oblique rounded
riblets ; in some places there are indications of fine obscure spiral
striation. Spire low, gradated, conoidal, its height about one-sixth of the
whole length of the shell. Protoconch lost. Whorls 7 to 8, those of the spire strongly
keeled a very short distance above the suture, the shoulder excavated ; body-whorl
elongated, tapering towards the base, where it is slightly contracted. Suture not
much impressed, simple. Aperture narrow, widening a little anteriorly, the margins
subparallel. Outer lip thin, acute, straight. Columella oblique, smooth, rounded.
Height, 23 mm. ; diameter, 12 mm. (holotype).
Holotype in the Otago University
.Museum, Dunedin ; presented by Professor P. Marshall.
Loc. — Komiti Point, Kaipara Harbour,
North Auckland : Marshall. — Miocene.
Remark. — C. heteroxpira Tate, from Victoria, is a nearly allied form.
Description.
Small for family
(height c. 25 mm), biconic, spire low, 0.2 total height. Protoconch conical, of
about 4 smooth whorls. Teleoconch of 7-8 whorls, sharply angled a very short
distance above suture; last whorl gently convex posteriorly, weakly excavated
below. Axial sculpture of weak nodules on periphery of first whorl, and fine
arcuate growth ridges on sutural ramp. Spiral sculpture of feeble threads on
ramp on some shells, and 10-12 grooves of variable width on anterior part of
last whorl. Aperture narrow, inner and outer lips almost straight and parallel;
outer lip with U-shaped sinus on ramp (1).
Comparison: This rather nondescript species is similar to Conilithes wollastoni (Pl. 22v) in some respects, but is
consistently lower-spired, and has peripheral nodules confined to the first
teleoconch whorl.C. lyratus (=
C. marshalli Finlay, 1926, unnecessary
name change; Otaian-Altonian, Pakaurangi Point) is similar in shape and axial
sculpture to C. armoricus, but has spiral grooves over the
whole of the last whorl; its status is uncertain, but it is probably a distinct
species (1).
Distribution: Otaian-Altonian,
Pakaurangi
Formation, Pakaurangi Point, Kaipara Harbour (type) (uncommon) (1).
Conus armoricus var. pseudoarmoricus (Marshall & Murdoch, 1920)
Shell small, spire low, gradated, the body elongated and sharply
tapering. Whorls six, excluding the protoconch, which is missing; each whorl with
a pronounced rim-like ridge, which overhangs and partly conceals the suture,
giving to the volution a distinctly concave appearance; the last whorl
immediately below the ridged shoulder slightly contracted.
Sculpture: On the spire-whorls four or five small spiral threadlets, on
the anterior area of the last about twelve well marked and obliquely ascending;
above these a few ill-defined lines which probably are continued to the crown;
axial growth-striae irregular, on the spire distinctly curved, indicating a
fairly deep sinus. Aperture narrow; the margins almost parallel; outer lip
imperfect.
Length, 18 mm.; width, 10 mm. Locality, Hampden. Collected by Dr.
Marshall. Type to be presented to the Wanganui Museum.
Differs from C. armoricus by the spiral threadlets on the spire,
the rim-like ridge which overhangs the sutures, and the accompanying concavity
of the whorls. The material consists of a single example.
C. pseudoarmoricus is recorded
from Komiti Point, C. armoricus occurs at Pakaurangi Point, not Komiti
Point, which is some two miles distant. Kaipara Harbour, and it is interesting
to find a form so nearly akin in the Hampden beds.
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Conus armoricus (1) Paratype Pakaurangi
Point, Kaipara Harbour, Otaian or Altonian (TM6856, GNS) New Zealand |
Miocene |
Conus armoricus
var. pseudoarmoricus (2) Pl.
VI – Fig. 10 mm.
18 x 10 Hampden – New
Zealand |
Bibliografia Consultata
·
(1)
- Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell
(1990)
·
(2)
- Marshall,
and Murdoch, 1920. Some Tertiary Mollusca, with Descriptions of New
Species. Transactions and Proceedings of the New Zealand Institute, 52
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