Phalium granulatum is a large helmet shell that has a height of approximately 60-80mm; the shell is thick, glossy and globular (1). The shell has a high spire, and 8 whorls, the last being the largest; the shell surface has 16-18 dissimilar spiral ribs (1). The columella is oblique, the aperture is oval, with siphonal canal and a posterior sinus; the outer lip has internal denticulation, and the operculum is large and horny, like a fan (1).
The colouration of the grooved helmet is a pale brown, with darker spots and four brown bands on the outer lip (1).
They paralyse their prey, the sea-urchin, using a toxic secretion, restricting its movement with their foot; before opening their shell with its radula (1).
P. granulatum live on sandy, muddy or detrital bottoms in the circalittoral zone (1).
The larval of P. granulatum takes over three months for pelagic development (3).
The grooved helmet is found in the Mediterranean, Atlantic, Caribbean, Azores, Madeira and Canary Islands (1; 2).
P. granulatum is carnivorous, feeding mainly on sea urchins using their toxic secretion to paralyse them (1).
Not listed under the IUCN Redlist (4).
Description written by Ben Harvey (2009)
(1) Delamotte, M. & Vardala-Theodorou, E., 2001. Shells from the Greek Seas. Athens: Goulandris Natural History Museum.
(2) Gofas, S. (2009). Phalium granulatum (Von Born, 1778). In: Bouchet, P.; Gofas, S.; Rosenberg, G. World Marine Mollusca database. Accessed through the World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=139026 on 2009-08-25
(3) Scheltema, R. 1971. Larval dispersal as a means of genetic exchange between geographically separated populations of shallow-water benthic marine gastropods. Biol Bull 140: 284-322.
(4) IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>. Downloaded on 25 August 2009.