Conus
(Hemiconus) constantinensis (Tracey et
al., 2017)
Descrizione e caratteristiche (1):
Small Hemiconus with a
large protoconch, stepped spire, smooth upper whorls, bicarinate nodular
periphery and spaced, granulated spiral cords.
Small biconical shell, spire 34%
of shell height; protoconch large, c. 725 μm., paucispiral of 1.75
whorls ; whorl profile concave above, smooth with faint growth striae and a
beaded subsutural collar ; rounded tubercles below crossed and truncated by two
prominent spiral cords; tubercles persist to the last whorl where they form a
nodular biangular shoulder. Last whorl slightly sinuous in profile, typically
ornamented with 11 spaced, granulated spiral threads c. 9 plain spirals
on the base. Sinus wide and shallow, aperture narrow with parallel sides ;
inner lip slightly concave centrally, outer lip gently curved. Up to 15.4 x 7.1
mm.
Discussion of H.
constantinensis n. sp. : This is broader than H.
disjunctus (Deshayes, 1865) which also lacks the granulated ornament.
Differs from H. granatinus (Deshayes, 1865) in the stepped profile, the
smooth and concave upper part of the whorls, the biangular peripheral cords and
by typically having fewer granulated spirals on the last whorl ; Néhou examples
may have up to 30 spirals below the biangular shoulder due to the development
of intermediary threads
Distribuzione: Late Lutetian, Faluns de
Hautteville-Bocage, upper part of unit FHB-A, Fresville (Manche).
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Hemiconus constantinensis mm. 15,3 Paratype NHMUK PI TG 26867 (leg. B. CRAIG) Fresville |
Hemiconus constantinensis
mm. 11,1 Paratype
NHMUK PI TG 26868 (leg. B. CRAIG) Fresville |
Hemiconus constantinensis mm. 13,0 Holotype
NHMUK PI TG 26869 (leg. B. CRAIG) Fresville |
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Hemiconus constantinensis mm. 10,8 Paratype
NHMUK PI TG 26870 (leg. S.
TRACEY) Néhou |
Hemiconus constantinensis
Paratype
NHMUK PI TG 26871 (leg. S.
TRACEY) Néhou |
Hemiconus constantinensis Paratype NHMUK PI TG 26872 (leg. S.
TRACEY) Néhou |
Bibliografia Consultata