young, 4 mm
Liloa porcellana (Gould,
|Maximum size: 24 mm
(extrapolated from shell length).
a transparent to translucent-white, cylindrical shell.
Spiral striae are confined to the apex and base when young but develop
over the entire shell in older individuals. (Note 1) The animal is
translucent-gray variably flecked with white and spotted with brown. It
may be distinguished from Liloa mongii by the absence of
spiral striae in the center of the shell when young and the slenderer,
more opaque shell with more irregular spiral striae when mature.
Natural history: Liloa porcellana is a moderately rare
species found in open sand and Halimeda
kanaloana beds at depths of 8-29 m (26-95 ft). Dredged shells at
the Bishop Museum extend the depth range to at least 311 m (1020 ft).
The number of shells found in sand samples suggests that it's more
common in deeper water. It is a nocturnal species that buries itself in
sand during the day and lays a white, spherical egg mass.
Big Island, Maui, Oahu and French Frigate Shoals. Probably widely distributed in
Many Hawaiian shells at the
Bishop Museum labeled Atys curta
are actually this
species as are many shells from elsewhere in the Pacific labeled Atys parallela (Gould, 1847). The descriptions and illustrations of Haminoea tomaculum in Pilsbry, 1917/1921 and Edmondson, 1946 may refer to this species rather than to Liloa curta. In that case, it was probably first reported from Hawaii in Pilsbry, 1917. It's illustrated in Severns, 2000 as Cylichna pusilla. It's may be the shell labelled Atys porcellana in Severns, 2011.
Photo: CP: 12 mm: Black Rock, Maui; June 6, 2012.
Observations and comments:
1: Rarely, shells are found in sand
samples that are inflated apically rather than cylindrical. Other
characteristics (that cannot be explained as part of that distortion)
seem to match the shells of this species and
we have seen
an example in which the shell appeared to have suddenly "inflated"
during the course of growth. Also, the degree of inflation is highly
variable. Therefore, we're treating them as atypical
examples of Liloa porcellana (perhaps due to injury,
disease or parasitism?) rather than as a separate species. (see photo).