Conus maga (Vokes, 1938)
Description.
Shell large,
spire relatively low, concavo-convex in outline, shoulder truncate;
nuclear whorls d6collet6; early post-nuclear volutions obscurely tuberculate,
later whorls excavate above, marked by numerous fine
microscopic striae which tend to be obsolete toward the outer edge, and by
prominent lines of growth; aperture
widened anteriorly, slightly flaring; outer lip moderately retractive, anal notch deep; siphonal notch wide, shallow; siphonal fasciole relatively wide;
anterior portion of body whorl sculptured by
irregularly spaced, rounded
spiral threads which are obscurely beaded (1).
This species
may be distinguished from C. stenostoma Sowerby, with which it has been confused, by the more deeply
excavate anal fasciole, the finer spiral sculpturing on the spire whorls, the nature of the sculpturing
on the anterior portion of the
body whorl, and by the wide,
shallow siphonal notch and the wide siphonal fasciole. C.
apium Woodring (1928, p. 202,
P1. ix, fig. 3) has a lower spire, more rounded shoulder and less deeply excavate anal fasciole. C. haitensis Sowerby
has a lower spire which is conspicuously
striate spirally (1).
Descrizione.
Si tratta di una conchiglia di grandi dimensioni, la cui spira è relativamente bassa. Il profilo è concavo-convesso, la spalla è troncata; le prime spire postnucleari sono oscuramente tubercolate, le spire successive sono incavate e sono segnate da numerose striature microscopiche e fini, che tendono ad essere obsolete verso il bordo esterno e da linee di crescita prominenti; l’apertura è allargata anteriormente, leggermente svasata; il labbro esterno è moderatamente retratto, la tacca anale è profonda; la tacca sifoninale è larga e poco profonda; la fasciola sifonale è relativamente larga; la parte anteriore del corpo è scolpito da fili a spirale arrotondati irregolarmente e distanziati, che sono oscuramente bordati.
Questa
specie può essere distinta dal C. stenostoma Sowerby, con il quale è
stato confuso, dalla fasciola anale più profondamente scavata, dalla scolpitura
a spirale più fine sui vortici della spira, dalla natura della scolpitura sulla
parte anteriore del corpo, e dalla tacca sifoninale larga e poco profonda e
dall'ampia fasciola sifonale.
Il C. apium
(Woodring, 1928: p. 202, Pl. IX, fig.
3) ha una pira più bassa, la spalla più arrotondata e una fasciola anale meno
profondamente scavata.
Il
C. haitensis Sowerby ha una spira più bassa, che è vistosamente striata
a spirale.
Conus (Dendroconus)
apium (Woodring, 1928)
Conus (Pyruconus) apium (Woodring,
1928)
Description
Shell
medium-sized, spire low, its outline slightly concave. Shoulder rounded and
broadly bulging. Anal notch very shallow, outer lip very slightly retractive as
it approaches anal notch. Anal fasciole flat, limited by a low obscure thread
concealed on spire by overlap of succeeding whorl. Sculpture consisting of
obscure wavy spiral threads on anterior half of body whorl (2).
Length 58
mm.; diameter 35.8 mm. (holotype).
This is
the species called C. solidus (Sowerby, 1850) by Guppy in 1866. In 1867
he discovered that this name was preoccupied, so he proposed the name recognitus.
It happens that Sowerby’s solidus is a different species (see p. 205). Inasmuch
as Guppy was renaming Sowerby’s solidus, recognitus should be
used for that species, even though Guppy may not have had any Dominican shells
before him (2).
C.
williamgabbi Maury
(Bull. Am. Paleontology, vol. 5, p. 200, pi. 31, fig. 2, 1917), which is found
only in the Baitoa formation, is larger and less pyriform, and the outline of
the spire is more concave (2).
“C.
recognitus Guppy’’ Pilsbry (Proc. Acad. Nat. Sci. Philadelphia, vol. 73, p.
327, pi. 19, fig. 2, 1922) is williamgabbi (2).
“C.
recognitus Guppy” Maury (Bull. Am. Paleontology, vol. 5, p. 209, pi. 33,
fig. 9, 1917), found in the Baitoa and Cercado formations, is smaller and more
slender than apium, though in other features the two species are very
similar (2).
C.
“molds var.” bravoi
Spieker (Johns Hopkins Univ. Studies in Geology, No. 3, pp. 41-42, pi. 1, fig.
6, 1922; Miocene, Peru) has the same kind of flat anal fasciole, but is larger
and stouter than apium (2).
No cones
similar to apium are now living in the West Indian region, but this
fossil species resembles C. pyriformis Reeve, living on the Pacific
coast of Central America. The Bowden species is larger and broader at the
shoulder, and has a lower spire. Apparently its early whorls are not
tuberculate, though they are worn on all of the few specimens. A young shell in
the Henderson collection referred to this species is more slender than would be
supposed from the adult shell. Three specimens are in the Duerden collection
and two in the Henderson collection (2).
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Conus maga (1)
Holotype
AMNH No. 24999 Miocene – Springvale (Trinidad) mm. 85,3 x
50,5 |
Conus apium (2)
Holotype USNM 369351 Upper Pliocene - Florida mm. 58,0 x 35,8 C. solidus (Sowerby, 1850) by Guppy in 1866 Conus recognitus (Guppy, 1876) |
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Conus maga (1)
Holotype,
No. 24999 mm. 85,3 x 50,5 |
Conus apium (2)
Holotype USNM 369351 mm. 58,0 x 35,8 |
Bibliografia Consultata