Key:  Family Columbellidae

Phylum Mollusca
  Class Gastropoda
    Subclass Prosobranchia
      Order Neogastropoda
        Suborder Rachiglossa

Taken primarily from  Kozloff, 1987, 1996 p. 226  (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)
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1a  Spiral ridges and grooves limited to the lower portion of the body whorl 2
1b Spiral ridges and grooves not limited to the lower portion of the body whorl 5
2a Uppor portion of body whorl with a well developed ridge (this is often of a lighter color than the rest of the shell); outer lip of aperture with a prominent indentation below the point where the ridge meets the lip; color generally yellow-brown to brown, sometimes with white or dark brown mottling (height to about 1 cm) Alia carinata
2b Upper portion of body whorl without a well developed ridge (in A. gausapata, there may be a slight ridge); outer lip of aperture without a prominent indentation (if there is a slight ridge on the body whorl, there may be an outwardy directed projection where the ridge meets the lip); color usually brown or tan 3
3a Outer lip of aperture evenly curved (periostracum brown; length to 1.5 cm, subtidal) Alia permodesta
3b Outer lip of aperture not evenly curved (a portion of it is nearly straight) 4
4a Siphonal region, when the shell is viewed with the aperture facing away from the observer, not obviously set off from the rest of the body whorl;  height to 1.1 cm; intertidal and subtidal (Alia gausapata in original key) Astyris gausapata
4b Siphonal region, when the shell is viewed with the aperture facing away from the observer, obviously set off from the rest of the body whorl;  height rarely more than 9 mm; subtidal Alia tuberosa
5a Axial ridges obviously not parallel to the long axis of the shell (they are directed slightly to the left as they extend downward); height rarely attaining 1.5 cm (often with distinctive light and dark markings unless the shell is covered with foreign material) Amphissa versicolor
5b Most axial ridges almost parallel to the long axis of the shell 6
6a Middle third of the outer lip of the aperture (in mature specimens, at least 2 cm high) parallel to the long axis of the shell (photo); height to 3 cm; common intertidal and subtidal species Amphissa columbiana
6b Middle third of the outer lip of the aperture (in mature specimens, at least 1 cm high) curved; height to 1.5 cm; subtidal, rare Amphissa reticulata



Taxonomic Levels Represented in This Key:

  Amphissa columbiana
  Astyris gausapata



Page created by Dave Cowles, 2007
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