SHELL OF THE MONTH JULY 2011

Most marginella are small shells often about 10-20 millimeters in size. There are exceptions. Our shells of the month are two of the largest, both being over 40mm. In addition they are large for their species. Thai fishing boats have been active in Burmese waters. Both specimens were collected by trawlers working off the coast of the Mergui Islands in the Andaman Sea during December of 2010

Marginella strigata (Unicolor Margin Shell) and Marginella Elegans (Elegant Margin Shell) are very similar. The obvious difference is one is patterned, the other not. Both are grey. The outer lip of  strigata is tan, elegans is deep red brown.

The following description is adopted from Wikipedia:

Marginella is a genus of small tropical and warm-water marine gastropods in the family  Marginellidae, the margin snails. It is the type genus of the family.

The shells of species in this genus are rounded, smooth and glossy, with a large aperture that appears to be toothed because it shows the edge of the collumellar folds. In many species the shells are colorful. The glossy surface of the shell results from the fact that the mantle covers most of the shell when the animal is active. The animal has a long siphon. When the animal is active, the foot extends much further out than the edge of the shell. Marginella are carnivorous and predatory. The shells of the species in this genus have spires which range from moderately elevated to flattened. The surface of the shell is glossy and porcellaneous, and it is often but not always colourful. The columella has four definite, subequal plaits on its anterior half. The outer lip is thickened, and generally denticulate inside, with distinct teeth or folds. The siphonal canal is not deeply incised. There is no operculum.

Marginella strigata Dillwyn, 1817
Trawled At 30-60 Meters
Mergui islands, Burma
Northern Andaman Sea 12/2010

Marginella elegans Gmelin, 1791
Trawled At 30-60 Meters
Mergui islands, Burma
Northern Andaman Sea 12/2010
 
 
 
 

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