Key:  Family Trochidae

Phylum Mollusca
  Class Gastropoda
    Order Archaegastropoda
      Suborder Trochina

Taken primarily from  Kozloff, 1987, 1996 p. 201 (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)
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1a  Height more than twice the diameter; interior of shell not pearly (aperture about one-fourth the height of the shell; lower portions of whorls sometimes bulging slightly; spiral ridges numerous on each whorl, varying slightly in width and spacing; height not more than 7 mm; shallow subtidal, on sandy and gravelly substrata) Halistylus pupoideus
(Carpenter, 1864)
1b Height much less than twice the diameter, interior of shell pearly  2
2a Columella with 1 or 2 small nodes (picture) 3
2b Columella without any nodes 5
3a Umbilicus covered by a callus, nearly always closed  4
3b Umbilicus open (picture) (periostracum brown) (Tegula pulligo in key)
4a Shell with purplish black periostracum, and with a scaly band below the suture; with 2 nodes on the columella (the lower one often worn away) (picture); mid-intertidal on open coast (Tegula funebralis in key) Chlorostoma funebralis
(A. Adams, 1855)
4b Shell with a brown periostracum, and without a scaly band below the suture; with 1 node on the columella; low intertidal, and not likely to be found north of Oregon (Tegula brunnea in key) Chlorostoma brunnea
(Philippi, 1848)
5a Umbilicus decidedly open 6
5b Umbilicus closed (picture) (caution: in young specimens it may be open) 15
15a Shell without spiral ridges, and with an almost waxy appearance (color usually white, yellowish, or pinkish); rare, not often encountered at depths of lesss than 100 m Calliostoma platinum
Dall, 1890
15b Shell with spiral ridges (picture), and without a waxy appearance; includes some intertidal as well as subtidal species 16
16a Spiral ridges beaded (picture, picture) 17
16b Spiral ridges not beaded (picture) 20
17a Beads on spiral ridges pronounced; base of body whorl decidedly convex; sutures between whorls deeply indented; periostracum gray, brown, or olive-green; subtidal 18
17b Beads on spiral ridges small and delicate (picture, picture); base of body whorl nearly flat (picture); sutures between whorls not deeply indented; periostracum not gray, brown, or olive-green, includes intertidal and subtidal species 19
18a Diameter about three-fourths of the height; periostracum gray or brown; height up to 4 cm; shallow subtidal Cidarina cidaris
(Carpenter, 1864)
18b Diameter more than three-fourths of the height; periostracum olive-green; height up to 6 cm; mostly at depths of more than 350 m Bathybembix bairdi
(Dall, 1889)
19a Shell usually orange-yellow, dotted with brown and with a bright purple or violet band encircling the lower edge of each whorl; with 8 or 9 whorls; body of living animal orange, with brown dorsal spots Calliostoma annulatum
(Lightfoot, 1786)
19b Shell almost uniformly yellowish, tan, or pale pink; with 6-8 whorls; body of living animal cream with brown dorsal spots Calliostoma variegatum
(Carpenter, 1864)
20a Whorls, as the shell is viewed in profile, almost flat; periostracum more nearly tan or brown than pinkish brown or reddish brown; not common Calliostoma canaliculatum
(Lightfoot, 1786)
20b Whorls slightly convex; periostracum usually pinkish brown or reddish brown, common Calliostoma ligatum
(Gould, 1849)

Taxonomic Levels Represented in This Key:

  Calliostoma annulatum
  Calliostoma ligatum
  Calliostoma variegatum
  Chlorostoma brunnea
  Tegula funebralis
  Tegula eiseni

Page created by Dave Cowles, 8-2004
Edited by:  Dave Cowles, 2005