Key: Subfamily Lacuninae of Family Littorinidae (Formerly
Family
Lacunidae)
Phylum Mollusca
Class Gastropoda
Subclass
Prosobranchia
Order Mesogastropoda
Suborder Taenioglossa
Family
Littorinidae
Taken primarily from Kozloff,
1987, 1996 p. 208 (Copyright
1987, 1996, University of
Washington Press. Used in this web page by permission of University
of Washington Press)
Note: This key is not
reliable for very young specimens
(shell height under 3 mm)
1a |
Height of aperture
nearly or fully two-thirds the height
of the shell |
2 |
1b |
Height of aperture
about half the height
of the shell (in some specimens of Lacuna
variegata the height
of the aperture
is slightly more than half the height
of the shell, but definitely not two-thirds the height) |
3 |
2a |
Shell glossy brown, often with lighter mottling,
without wrinkles,
but sometimes with faint spiral lines; height
up to about 6 mm (not likely to be found north of Oregon) |
Lacuna (Lacuna) marmorata |
2b |
Shell dull grown, usually without mottling, but with
microscopic wrinkles
(in general, the wrinkles are oriented in much the same way as spiral
lines
or ridges,
but they are more irregular) |
Lacuna (Lacuna) porrecta |
3a |
Shell mostly light tan, with chevron markings of brown
under a thin,
dull periostracum;
without distinct spiral lines; larger whorls
sometimes with a slight, flattened shoulder; height
up to about 7 mm; common on Zostera (eelgrass) in
bays (not likely
to be found south of Washington) |
Lacuna
(Epheria) variegata |
3b |
Shell tan or brown, usually with a broad, whitish
spiral band under
a glossy periostracum;
with fine spiral lines; whorls
evenly rounded; height
up to 1.3 cm; on algae on rocky shores (not likely to be found south of
Washington) |
Lacuna
(Epheria) vincta |
Taxonomic
Levels Represented
in This Key:
Lacuna
variegata
Lacuna vincta
Page created by Dave Cowles, 2008
Edited by:
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