MURICIDAE
murex shells

  Thais sacellum
(Gmelin, 1791)

Relevant Synonyms
-

Misidentification
Thais rugosa (Born, 1778) [Bosch et al., 1995]

 photo: S. Gofas / Coll. H. Zibrowius    

SHORT DESCRIPTION
Shell massive, solid, of 6-7 whorls, of which the body whorl makes about two-thirds of total height. Whorls with a distinct spiral keel bearing ragged, projecting knobs; and with squamose spiral cords, separated by intervals as broad as the cords. Body whorl with 3-4 larger spiral cords on which the small cords are set close together, and the umbilical chink surrounded by a thickened structure. Aperture ovate, terminating anteriorly in a small, short siphonal canal. Outer lip somewhat thickened inside, with 9-10 denticles extending far inside the aperture.

color : outside of a yellowish tan color, with dark brown mottles or flames over the spiral cords only, attenuated in the intervals. Inside of aperture white.

common size : 30-40 mm.

DISTINGUISHING CHARACTERISTICS
This species is distinguished from other Thais by the peculiar sculpture of squamose cords and the pure white inside of aperture. A similar sculpture may occur locally on the Atlantic species Nucella lapillus, but never with the 3-4 major cords and keel on the body whorl. Mancinella rugosa (Born, 1778) is a different taxon, but Murex rugosus as figured in Born (1780) is as this species, hence the nomenclatural confusion.

BIOLOGY / ECOLOGY
Unknown.

habitat : in Indian Ocean under rocks (Bosch et al., 1995); in the Mediterranean, this species has so far been found on hard substrates in a harbour environment.


1st Mediterranean record
Beyrouth, Lebanon, 2003 [2000].


DISTRIBUTION
Worldwide: Indian Ocean: Nicobar Islands (type locality of Thais sacellum), Masirah (Bosch et al., 1995), Red Sea (Dekker and Orlin, 2000). Mediterranean: observed first in 2000, in Beyrouth, Lebanon (Zibrowius and Bitar, 2003); its distribution seems limited to Lebanon.

ESTABLISHMENT SUCCESS
Locally common, particularly in Beyrouth area. Recent work by G. Bitar has revealed another specimen from the Ras El Chakaa area, north of Beyrouth, much closer to Tripoli.

speculated reasons for success :
-


MODE OF INTRODUCTION
Presumably by shipping.


IMPORTANCE TO HUMANS
None.


KEY REFERENCES

  • Bosch D.T., Dance S.P., Moolenbeek R.G. and Oliver P.G., 1995. Seashells of Eastern Arabia. Motivate Publishing, Dubai, 296 p. [Thais sacellum p. 123].
  • Dekker H. and Orlin Z., 2000. Check list of Red Sea Mollusca. Spirula, 47(suppl.): 1-46.
  • Zibrowius H. and Bitar G., 2003. Invertébrés marins exotiques sur la côte du Liban. Lebanese Science Journal, 4(1): 67-74.

 

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Last update : January 2005

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