ISSN 1063-0740, Russian Journal of Marine Biology, 2006, Vol. 32, No. 5, pp. 316–318. © Pleiades Publishing, Inc., 2006.
Original Russian Text © E.V. Kozminskii, P.A. Lezin, 2006, published in Biologiya Morya.
Gastropods are classical objects for studying the dif-
ferent genetic processes in populations. Particularly,
features of shell color are used as markers of genotype.
However, subjectivity and ambiguity in the color deter-
mination of the different elements of the shell color
present a serious problem. This makes it difﬁcult to
compare data from different investigations, does not
permit simple characterization of phenotypes, and, in
some cases, does not permit us to formulate exact crite-
ria for the individual specimens' afﬁliation with a par-
ticular phenotypical group.
Attempts at using standard diagrams of the colors of
Mansell and Osvald were made in order to eliminate
ambiguity in color determination [3–5]. However, such
an approach is not sufﬁciently effective because of indi-
vidual peculiarities in color perception. The use of
accurate colometric methods may solve this problem.
In the present work, a simple and effective method of
color measurements based on the computer analysis of
the digital images of the shell was examined.
MATERIAL AND METHODS
Adult individuals of
1758), collected on Ivanov-navoloka in the Chupa Inlet
(Kandalashsky Bay, White Sea), were used as a mate-
rial for color measurements. Measurements were made
for 70 mollusks belonging to the 13 color morphs in the
system suggested by Sergievskii and coauthors .
Before the experiment, all soft tissues were
extracted from the shell by submerging mollusks into
boiling water for 10–15 s. Then, the shells were dried in
a thermostat at 35
C and measurements were made.
Digital images of the shell were obtained using an
Epson Perfection 1670 Photo scanner. Pans made of
thin organic glass with attached shell were turned over
and placed into the scanner. Plasticine was used for
shell attachment. Shells were arranged in such a way
that during pan ﬂipping, the measured parts of shells
touched the glass of the scanner. Scanning was per-
formed at 1200 dpi.
Color measurements were made using Image Tool
(htttp://ddsdx.uthscsa.edu/). The color coordinates of
the elements of pigmentation were stated in the MKO
RGB international colometric system.
The fact that every color may be represented as a
mixture of a particular number of three linearly inde-
pendent colors—red, green, and blue—is the basis for
the quantity color description in MKO RGB . The
value of every color may vary from 0 to 256 in the
MKO RGB system. A value of all colors equal to zero
corresponds to black, and a value of 256 corresponds to
white. Red, green, and blue form rectangular coordi-
nates, so called color coordinates (see ﬁgure). The three
numbers that characterize a speciﬁc color are the
amount of the basic colors in a mixture, the colors that
are not visually distinguished from the given color, and
the so-called color coordinates.
The character of the background stain and color of
the separate elements—blocks and stripes  in the ten
points of the last turns of the shell—were deﬁned for
each mollusk; then, the mean value was calculated.
The color parameters of the background stain of per-
iwinkles were characterized by the high variability of
the red and green color components and a quite low dis-
persion of the blue component (see table). The value of
the blue component in all examined phenotypes ﬂuctu-
ated from 20 to 61, when the range of deviation of the
other two colors reached 28–208. In the red and green
spectra, periwinkles with brown and yellow colors
occupied opposite positions in the line from black to
METHODS OF INVESTIGATIONS
Method of Color Measurements of the Elements of Color
in Gastropods Shell
E. V. Kozminskii and P. A. Lezin
White Sea Biological Station of the Institute of Zoology, Russian Academy of Sciences, St. Petersburg, 199034, Russia
Received February 9, 2006
—The method of the accurate determination of the shell color of gastropods has been studied with the
example of the gastropod
. The suggested method is based on using the system of MKO RGB
color coordinates and makes it possible to conduct measurements of both color as a whole and the color of the
individual elements of the shell picture.
polymorphism, color of the shell of the mollusks, color measurements,