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Additional Photos
underside
young
shell
egg mass
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GALLERY
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Atys semistriatus Pease, 1860
Maximum size: 17 mm
(extrapolated from shell length).
Identification:
This
species has a transparent shell with crisp spiral striae on the
apex and base. The shell is widest below the midline. The animal is
translucent cream with brown flecks on the head and parapodia. Pink
spots show through the shell and increase in prominence with age. It
may be distinguished from young Atys kuhnsi by the shell
profile, lack of striae on the center of the shell when mature and
smaller eye spots.
Natural history:
Atys semistriatus
is one of the most common haminoeids in Hawaii. It is found in rocky
and mixed habitats from < 1 to 29 m (< 3 to 95 ft) but is only
occasionally found in Halimeda
kanaloana beds. It occurs in protected to exposed sites and is
nocturnal in habit, concealing itself under rocks or in underlying sand
during the day. When the population is high, mating aggregations with
copulating pairs can often be seen on top of coral rubble or rocks at
night. It lays a spherical, white to pale pink egg mass that is usually anchored in
algal turf in the field.
Distribution:
Big Island, Maui, Oahu, Kauai, Niihau, French Frigate Shoals, Laysan, Lisianski, Pearl
&
Hermes Reef, Midway and Kure (also Johnston Atoll): widely distributed in the Indo-Pacific.
Taxonomic notes:
This species is listed as Atys semistriata
in Kay, 1979 and Kay & Schoenberg-Dole, 1991.
However, the photo in Kay & Schoenberg-Dole, 1991 is probably Atys kuhnsi, instead. It
was first reported from Hawaii in Pease, 1860. Atys semistriata mua Pilsbry, 1921 and Atys semistriata fordinsulae Pilsbry, 1921 are synonyms (Kay, 1979).
Photo: CP:
Hekili Point, Maui; Oct. 30, 2004.
Observations and comments:
Note
1: ( )
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