Colus griseus (Dall, 1890)

Common name(s):   Gray whelk

Synonyms: Plicifusus griseus Colus griseus
Phylum Mollusca
Class Gastropoda
Order Neogastropoda
Suborder Rachiglossa
Colus griseus shell collected dead from a red octopus (Octopus rubescens) midden.  Shell height is 1.5 cm, width 0.7 cm.
(Photo by: Dave Cowles, March 2008)
Description:   As with other members of family Neptuneidae, this snail has a raised spire, a well-developed siphonal canal but the anterior portion of the body whorl and canal are not set off from the rest of the body whorl by a conspicuous groove.  It has no anal notch, less than 8 whorlsColus griseus is less than 3x as high as its diameter.  It has both axial ribs and spiral ridges.  The 23-28 low, broad axial ribs extend onto the body whorl but disappear or become indistinct on the anterior half of the body whorl.  The spiral ridges are small and closely spaced and of similar size.  The whorls do not have distinct angular shoulders.  It has no folds on the columella nor on the inside of the outer lip of the aperture (photo).  The outer lip of the aperture has a concave curve where it meets the siphonal canal.  The siphonal canal is less than half the total length of the aperture.  The height is up to 3 cm.

How to Distinguish from Similar Species: Mohnia freilei, another rare subtidal species, has 12-15 axial ribs per whorl and only reaches 1.8 cm height.

Geographical Range:  Pacific

Depth Range:


Biology/Natural History:  This is a rare subtidal species.

While Kozloff (1987, 1996) classify this species in Family Neptuneidae, The American Fisheries Society (1998) and ITIS (2008) place it in family Buccinidae.



Dichotomous Keys:
  Kozloff 1987, 1996 (as Plicifusus griseus in family Neptuneidae)

General References:
 American Fisheries Society, 1998

Scientific Articles:

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:
 I have not found this species near Rosario, but apparently red octopus have because this was in the beer bottle midden of a red octopus at about 18 m depth on Whidbey Island.

This photo shows the aperture.  The shell has obviously been dead for awhile and has the remnants of a bryozoan growing within the aperture as well as some missing shell on the outer lip of the aperture.
Note how the axial ribs disappear on the anterior half of the body whorl, while the finer spiral ridges are still visible. 

2.4 cm shell
This live individual is 2.4 cm long.

Here is the same individual, crawling along the side of an aquarium at the surface of the water. Note the extended siphon and the whitish foot with a horny operculum. Photo by Dave Cowles, August 2018

Head-foot-siphonThis individual (the same as the 2.4 cm one above) seems perfectly willing to gradually come out of the shell when I hold it upside-down. .Here the foot, head with eye, and inhalant siphon can be clearly seen stretching from the aperture as I hold the shell. Note the hole nearly bored through the shell near the rear of the foot. Photo by Dave Cowles, August 2018

Authors and Editors of Page:
Dave Cowles (2008):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)