MYTILIDAE
mussels

  Septifer forskali
Dunker, 1855

Relevant Synonyms
Septifer bilocularis var forskali [Oliver, 1992]

Misidentification
Septifer bilocularis [Albayrak and Çeviker, 2001]

 photos: D. Çeviker    

SHORT DESCRIPTION
Shell solid, equivalve, inequilateral. Outline mussel-like with subterminal umbones. Sculpture of many strong radial, occasionally bifurcating, ribs crossed by finer concentric lines giving them a nodulous appearance. Hinge with 2-3 large teeth below the umbo, 4-6 large dysodont teeth behind the ligament. Septum across umbonal cavity. Inner margin crenulate. Periostracum of simple long fine bristles.

color : externally light green with orange pink spots. Internally, light green and pink tinted.

common size : in Red Sea up to 11.5 mm (Dekker, pers. comm.); the Mediterranean specimen smaller (the biggest 9.5 x 5 mm).

DISTINGUISHING CHARACTERISTICS
Similar to Brachidontes pharaonis externally but internally with a septum beneath umbones. Differs from the Indo-Pacific Septifer bilocularis in size - S. bilocularis can attain a length up to 50 mm - and in color - S. bilocularis is typically red, blue or green.

BIOLOGY / ECOLOGY
Suspension feeders, epifaunal, actively mobile. The biology, ecology and use as a bioindicator of its congeneric S. bilocularis has been studied by Ompi and Lumingas (1997) and Kavun (1996).

habitat : attached by byssus to rocks and debris (corals, shells), lower shore and shallow water. The Mediterranean specimen was found attached to a Spondylus spinosus shell, at a depth of 40 m.


1st Mediterranean record
Southeastern Turkey, 2001 [2001].


DISTRIBUTION
Worldwide: Red Sea. Present in the Suez Canal (Moazzo, 1939 as Septifer bilocularis var forskali). Mediterranean: recorded only from southern Turkey: a first record in 2001 in Yumurtalik (Albayrak and Çeviker, 2001), then in the Iskenderun area at a depth 5-7 m (Çeviker, identification confirmed by A. Zenetos on the basis of photo).

ESTABLISHMENT SUCCESS
Extremely rare; only two specimens found in different southeastern Turkey sites.

speculated reasons for success :
-


MODE OF INTRODUCTION
Unknown; its absence from the Levantine coast does not support the hypothesis of a progressive penetration through the Suez Canal.


IMPORTANCE TO HUMANS
None.


KEY REFERENCES

  • Albayrak S. and Çeviker D., 2001. Two extra-Mediterranean mollusks from southeast Turkey: Siphonaria belcheri Hanley, 1858 [Gastropoda: Siphonariidae] and Septifer bilocularis (Linnaeus, 1758) [Bivalvia: Veneridae]. Israel Journal of Zoology, 47: 297-298.
  • Kavun V., 1996. Composition of microelements in the tissues of bivalves Barbatia barbata and Septifer bilocularis from Matupi Harbour (Papua New Guinea) influenced by hydrothermal activity. Marine Biology, 22(5): 318-322.
  • Moazzo P.G., 1939. Mollusques testacés marins du Canal de Suez. Mémoires de l'Institut d'Egypte, 38: 1-283, Cairo [Septifer bilocularis L. var forskali Dkr, p. 48].

 

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Last update : January 2005

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