with white flecks
young, 2.8 mm
probable food worm
Chelidonura alisonae Gosliner, 2011
|Maximum size: about 13 mm
on top of the head are enclosed by orange loops
and the underside is reticulated with orange. The sides are decorated
with rows of blue spots (the number, apparently, increasing with age)
and the notum is variably flecked
is a common diurnal species found in protected to exposed locations. It
occurs in rocky habitats at depths of 1-3 m
(3-10 ft). It
appears to feed on the small acoelomate flatworm Convolutriloba longifissura. (Note
1) A fringe of sensory
hairs at the front of the head is used to detect prey and it secretes a
yellowish fluid when disturbed. In dishes, its
egg masses are small, irregular, white clumps composed of an irregular
string. However, it is likely that they remain sack-like when laid in
the field where their sticky surfaces can collect detritus for
reinforcement. Hatching occurs in about four days in the laboratory.
Big Island, Maui, Molokai, Oahu, Kauai, French Frigate Shoals, Pearl & Hermes Reef and
distributed in the
central Pacific; also in the eastern Pacific.
hirundinina in Kay,
1979 (right hand drawing) and
Bertsch and Johnson, 1981. (Note 2) It is
illustrated in the inset photo under C.
hirundinina in Hoover, 2006. It was named after Dr. E. Alison
Photo: CP: 10
mm: found by PF; Maalaea Bay, Maui; Oct 21, 2002.
Observations and comments:
1: Several times in 1998 and 2002
animals were placed in dishes with 1.5-2 mm specimens of Convolutriloba longifissura (tentatively listed by Poulter as Convoluta sp. in section two of
Reef and Shore Fauna of Hawaii, 1987). They fed readily on the worms but
had a much slower feeding strike than either Chelidonura hirundinina or Chelidonura fulvipunctata allowing
details to be easily seen. The pharynx was everted sufficiently to form
a short tube and the worm was sucked in "spaghetti-fashion". The Chelidonura struck immediately on
contact with the worms and showed no sign of regurgitation or rejection
(unlike C. fulvipunctata
which engulfed, then regurgitated and C.
hirundinina which tested, then rejected in some cases). It's my
subjective impression that the worms showed a stronger aversive
response to contact with Chelidonura
alisonae than with the other two Chelidonura
spp. So, there's a good chance that C.
alisonae is the species
that actually feeds on Convolutriloba longifissura in the field.
Note2: Though held in
dishes with C. hirundinina on
many occasions, no sign of copulation between the two has been
observed in contrast to many instances of copulation within the
species. This supports the distinction between them.