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Additional Photos
pale
side
underside
young, 4 mm
extended cerata
contracted cerata
contracted rhinophores
on hydroid
egg masses
veligers
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Tenellia sp. #25
Maximum size: 20 mm.
Identification:
This
is
a translucent-cream aeolid frosted with bluish white. The
rhinophores are closely spaced with translucent-white tips and,
sometimes, translucent-orange bases. The cerata have brown cores and
bluish white
tips with subapical orange rings. It differs from the similar appearing Anteaeolidiella cacaotica in lacking
obvious cnidosacs in the tips of its cerata.
Natural history:
Tenellia sp. #25 is
a moderately common aeolid. Most of the animals we've seen were found in
association
with the introduced hydroid Pennaria
disticha in silty Halimeda
kanaloana beds at depths of 8-12 m (26-39 ft). However, it has also be found in tide pools (by Heidi Miller as reported on The Odyssey of Dai Mar site) and in shallow, moderately exposed rocky habitats where it's host hydroid is common. In a dish, one
animal showed a strong preference for resting on the hydroid and clung
tenaciously to it. It was observed feeding on the stalks of the
hydroid, though it ignored the polyps. Several pale pink, arc-shaped
egg masses were attached
to the base of the P. disticha
colony when it was collected and the animal subsequently laid several
comparable masses in a dish. The egg masses swelled during
development and one hatched in about five days in the laboratory. (Note 1)
Distribution:
Big Island, Maui and Kauai: also known from Guam, South Africa and French Polynesia.
Taxonomic notes:
It was first
recorded
in Hawaii from Maalaea Bay, Maui by CP on May 5, 2008 and was formerly placed in the genus Catriona.
Photo: CP: 15
mm: Maalaea Bay, Maui; May 5, 2008.
Observations and comments:
Note
1: Jenna Szerlag reported seeing one
contract its rhinophores, accordion-fashion, then relax them by about six minutes later. (see photos) Perhaps, it was responding to something in the water?
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