RISSOIDAE

  Alvania dorbignyi
(Audouin, 1826)

Relevant Synonyms
Alvania dorbignyi perversa Nordsieck, 1972
Rissoa dorbignyi Audouin, 1826

Misidentification
-

 photo: J. J. van Aartsen / La Conchiglia    

SHORT DESCRIPTION
Shell with a conical spire of moderately convex whorls. Body whorl rounded, with no umbilicus. Sculpture of broadly rounded axial folds, which are not continued below the periphery of the body whorl, and of spiral cords (four on last spire whorl), separated by interspaces as broad as the cords. Aperture ovate, with cutting outer lip, thickened by a varix at a short distance from the edge.

color : buff with dark brown lines (sometimes discontinuous) running over the cords. Aperture with a brown stain on the columella and another on the abapical part of the outer lip.

common size : 2 - 2.5 mm.

DISTINGUISHING CHARACTERISTICS
This species resembles the native Alvania montagui (Payraudeau, 1826), and other native species belonging to the same species group, which is in need of revision. The most likely to be confused are forms assigned to Alvania lineata Risso, 1826, which have also continuous brown lines on the spiral cords but differ in being more solid, and in having more raised axial folds which reach closer to the umbilicus on the base of the shell.

BIOLOGY / ECOLOGY
Unknown.

habitat : unknown, probably among infralittoral brown algae like the related species.


1st Mediterranean record
Haifa, Israel, 1982 [1958].


DISTRIBUTION
Worldwide: original distribution uncertain with records from the northern Red Sea; similar forms occur in the Indo-Pacific as far as New Caledonia; rare in the Bay of Suez (Moazzo, 1939). Mediterranean: recorded first from Israel in 1958 (van Aartsen, 1982; Nordsieck, 1972b); later from Cyprus (Cecalupo and Quadri, 1996).

ESTABLISHMENT SUCCESS
Moderately rare, found in appreciable numbers from 1958 onwards (van Aartsen, pers. comm.).

speculated reasons for success :
-


MODE OF INTRODUCTION
Possibly via the Suez Canal. The status of this species as an immigrant has been questioned by Mienis (1985c), who contends that it is a native Mediterranean species and that Red Sea occurrences may be due to north-south migration through the Suez Canal. Although this question is not settled, we have included this species following the advice of van Aartsen.


IMPORTANCE TO HUMANS
None.


KEY REFERENCES

  • Mienis H.K., 1985c. Is Alvania dorbignyi (Audouin, 1826) a lessepsian migrant? Levantina, 59: 652.
  • Nordsieck F., 1972b. Die europäischen Meeresschnecken (Opisthobranchia mit Pyramidellidae; Rissoacea). Vom Eismeer bis Kapverden, Mittelmeer und Schwarzes Meer. Gustav Fischer, Stuttgart. XIII + 327 p. [Alvania dorbignyi, p. 193].
  • van Aartsen J.J., 1982. Tavole sinottiche di conchiologia Mediterranea ed Europea (Gen. Alvania). La Conchiglia, 158-159: 4-5.

 

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Last update : December 2003

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