Conus
significatus (Nomura, 1935)
Descrizione (1).
Shell medium in size, obconical: test moderately
thick. Spire very low; apex acute, decidedly
concave in general outline. Whorls 12, apical ones embryonal, smooth and
globular; post-embryonal ones shouldered and spirally striated; angle of
shoulder minutely granulated on earlier whorls, more or less undulate on later
ones; striae 4-5 in number, crossed by rather distinct, oblique, growth lines,
making surface appear more or less granular. Body-whorl large, outline
straight, peripheral angle acute; spirally grooved throughout; grooves about
45, rather unequal, wider on lower part than on upper. Outer lip fractured;
aperture apparently narrow, straight, parallel sided as in C. sieboldi.
One specimen; 47 mm. in
height, 22 mm. in diameter, and 42 mm. in the length of aperture.
Compared with the preceding species, this shell
has a spire less elevated and more concave in outline; revolving grooves and
ridges are more extensively marked upon its body-whorl. C. decollatus martin
from the Neogene of Java somewhat resembles the Formosan fossil, but
differs in its much smaller shell with a different sculpture.
Fossil occurrence: Byoritu Beds.—Wangwa: station 24; Reg. No. 52394.
Pliocene,
Taiwan.
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Conus significatus(1)Pl. VII fig. 2 Byôritu Beds, Taiwan |
Bibliografia
·
(1)
Nomura, S., 1935. Catalogue of the Tertiary and Quarternary Mollusca from the
Island of Taiwan (Formosa) in the Institute of Geology and Palaeontology,
Tôhoku Imperial University, Sendai, Japan Part 2, Scaphopoda and Gastropoda. Sci. Repts. Tôhoku Imp. Univ. Sendai., 18
(2 ): 53 -228
·