Sturday     April 10, 1999   11:55 PM
 
Dear Friends,
 
Even though I don't see many Oliva enthusiasts on
CONCH-L I would like to narrate something about
one of these wonderful shells.
 
The best way to identify a shell would be to compare
it with the holotype and - or the original description
made by its Author. But this correct procedure is rarely
possible with the species named throughout the last
Century. The holotype often does not exist and in its
place sometime there is a not clear drawing. On the
other hand the descriptions are only brief notes
usually not sufficient to identify surely a species.
 
In far back 1811 Lamarck described a large Oliva
( about 80 mm ) where the white background is
overlaid with a brown pattern. White also the aperture,
it had a cylindrical shape. He called it Oliva pica.
There is no further information in Lamarck ( 1822 :
419, sp.n.4) and there is no reference illustration.
 
Few years later, on 1835, Duclos described Oliva
olympiadina, another large shell. The 2 syntypes
in the National Museum of Natural History, Paris
have a size of 74 and 69 mm. One is almost solid
ivory-white, the other has a brown pattern over a
light background. Their shape is very similar to
Oliva miniacea Roding, 1798.
 
In the following years, 1850, Reeve was studying
a large series of specimens from Mauritius (Western
Indian Ocean). Reeve selected a fine specimen
(now in Natural History Museum, London - from
the Cuming collection) to illustrate what he believed
to be Oliva olympiadina Duclos, 1835.
Reeve made a mistake giving that name to a large
still undescribed Oliva species.
 
After that mistake the recent Authors and many
collectors used the Lamarck and Duclos' names
in the wrong way.
 
The new Oliva from Western Indian Ocean was
identified as :
 
- Oliva tremulina c.f. olympiadina Duclos, 1835 by
  Zeigler and Porreca (1969).
 
- Oliva pica c.f. olympiadina Duclos, 1835 by
  Petuch and Sargent (1986)
 
- Oliva olympiadina Duclos,
  by Kaicher (1989) Card n. 5513
 
Even though Authors and collectors knew the existence
of this rather obvius species after about 150 years it
was still mistakenly identified.
 
Tursch and Greifeneder on 1996 studying the
"Oliva miniacea complex" discovered the error made by
Reeve. Consequently they realized that , at this
point, the Oliva was still unnamed.
On APEX vol.11(1), 1996 p.24 they finally described
the shell and called it Oliva mascarena. Etymology :
named after Mascarene Islands.
The rather cylindrical shell is of medium to large size.
The protoconch and the width of the filament channel
are similar to those of the other large Oliva species
which occour in the Indian ocean, such as O.miniacea
tremulina and O.ponderosa. The ground color is
ivory white. Prevalent blurred and diffuse pattern
elements are purplish-grey with marking brown to black.
 
About the Lamarck name "pica" it is now considered
a "nomen dubium".
About the Duclos name "olympiadina" it is now
considered as a local color form of Oliva miniacea
tremulina Lamarck, 1811.
 
Hoping you are not bored to death...kindest regards
to all.
 
Maurizio.
 
======================
       Maurizio A. Perini
       Via Pedrazza, 9
       I - 36010 Zane (VI)
       I T A L Y
 
  Voice  +39.0445.380378
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