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Additional Photos

dark

young, 3 mm

mating

shell

egg mass
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GALLERY

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Diniatys dubia (Schepman, 1913)

Maximum size: 26 mm.
Identification:
The
shell
of this species is transparent to slightly translucent. With
growth, it becomes proportionately more elongate and, in fully mature
animals, the outer lip becomes slightly thickened. Very small shells
(up to 2-3 mm) have fine, evenly spaced axial folds and spiral striae
completely covering their surfaces. In larger shells, that sculpture
becomes progressively
restricted to the apex and base. (see photo) The animal is
cream to olive-brown, flecked with white, and a dendritic
network of red-brown lines shows through the shell.
Natural history: Diniatys dubia
is
moderately rare in mixed habitats and sand channels at protected to
moderately exposed sites where it occurs at depths of as little as 1 m
(3 ft). However, it is one of the most common Hawaiian haminoeids in Halimeda kanaloana beds at depths
of 9-29 m (30-95 ft). Dredged shells
from the Bishop Museum extend the depth range to at least 183 m (600
ft). It appears to be largely nocturnal in habit but mating
aggregations of up to several dozen animals may remain in the open
during the day in the Halimeda
beds. It lays a spherical white egg mass that is more flaccid in
texture than that of most haminoeids. In the field, the egg masses are
usually attached to the tips of Halimeda
branches, decorating them like Christmas tree ornaments when the
population is high. (see photo)
The
eggs
hatch in about four days in the laboratory.
Distribution:
Maui, Oahu, Kauai and French Frigate Shoals: widely distributed in the
Indo-Pacific.
Taxonomic notes:
This species is listed in Gosliner, et. al. (2008), as Haminoea sp. 2. Immature
shells at the
Bishop Museum labeled Atys costulosa
Pease, 1869b appear to be this species as do mature shells labeled "Diniatys monodonta?". It was probably first reported from Hawaii in Pease, 1869
(as Atys costulosa).
Photo: CP: 19
mm: Wahikuli Park, Maui; May 1, 2005.
Observations and comments:
Note
1: ( )
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