Colus (Aulacofusus)

Colus esychus, copyright Jacksonville Shell Club.

Belongs within: Colini.

The subgenus Aulacofusus of the genus Colus is a group of whelks found in cold waters of the Northern Hemisphere.

Characters (from Kosyan & Kantor 2013): Shell elongated-fusiform, medium-sized, sculptured by wide spiral cords (from 6 to 16 on the penultimate whorl); axial sculpture represented only by incremental growth lines. Last whorl about two-thirds of shell length, with well-defined, moderately long, straight or slightly curved to left siphonal canal. Aperture not high, less than half of shell length; operculum oval with terminal nucleus. Central tooth of radula consisting of wide rectangular plate with normally three short thick sharp cusps, of which intermediate one the longest. Lateral teeth bearing three cusps with the shortest intermediate one; teeth rows not overlapping. Proboscis very long (length sometimes more than shell height), several times coiled within thin-walled rhynchodaeum; buccal mass is 4-5 times shorter than proboscis length. Salivary glands large, not fusing beneath rhynchodaeum; salivary ducts thick-walled, with additional external layer of longitudinal muscle fibres. Stomach large as compared to proboscis, narrow, with extremely long posterior mixing area, comprising half of stomach length.

Colus (Aulacofusus Dall 1918) O27
    |--C. (A.) acosmius Dall 1891 O27
    |--C. (A.) barbarinus Dall 1919 O27
    |--C. (A.) bristolensis Dall 1919 O27
    |--C. (A.) calameus Dall 1907 O27
    |--C. (A.) calathus Dall 1919 O27
    |--C. (A.) capponius Dall 1919 O27
    |--C. (A.) esychus Dall 1907 O27
    |--C. (A.) halidonus Dall 1919 O27
    |--C. (A.) herendeeni Dall 1902 O27
    |--C. (A.) nobilis Dall 1919 O27
    |--C. (A.) ombronius Dall 1919 O27
    |--C. (A.) periscelidus Dall 1891 O27
    |--C. (A.) roseus (Dall 1877) [=Chrysodomus roseus] O27
    |--C. (A.) sapius Dall 1919 O27
    `--C. (A.) spitsbergensis (Reeve 1855) [=Buccinofusus spitsbergensis] O27

*Type species of generic name indicated

REFERENCES

Kosyan, A. R., & Y. I. Kantor. 2013. Revision of the genus Aulacofusus Dall, 1918 (Gastropoda: Buccinidae). Ruthenica 23 (1): 1–33.

[O27] Oldroyd, I. S. 1927. The Marine Shells of the West Coast of North America vol. II pt I. Stanford University Press: Stanford University (California).