Kaburakia excelsa Bock,
1925
Common name(s) Giant flatworm, Giant
leaf worm
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Synonyms: |
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Phylum Platyhelminthes
Class Turbellaria
Order
Polycladida
Family Stylochidae |
Kaburakia excelsa, about 9 cm
long. Found under a rock
on Sares Head, Rosario Bay |
(Photo by: Dave Cowles,
June 2003 |
Description: This
giant flatworm has
a band of eyespots along the entire margin of the body (may not be
visible
except in transmitted light), plus on its pair of short, blunt nuchal
tentacles (picture),
at the bases of
the tentacles, and in the region of the brain. Its gut
outline follows
the multi-branching polyclad pattern. The color is tan with
small
spots or streaks of dark brown dorsally, lighter tan with few if any
spots
ventrally (picture).
Has no suckers
on the ventral surface.
How to Distinguish from
Similar Species: This
species if far larger than any other species in this area, and is one
of
the largest in the world. Most other flatworms in this area
are up
to only about 3 cm long. Polyclads are the only group of
flatworms
in our area that get larger than microscopic size.
Geographical
Range: Sitka, Alaska
to Newport Harbor, CA
Depth Range: Mid-intertidal
to subtidal.
Habitat: Among
mussels and under rocks,
sometimes on pilings or on boat bottoms among fouling organisms.
Biology/Natural
History: The tentacles
are just in front of the brain and can be retracted. This
animal
is negatively phototactic. The margins of the body wrinkle as
the
animal moves (see photo above). Will eat mussel tissue in the
laboratory.
In Washington, gravid individuals can be found in March.
150-160
golden yellow eggs are laid individually in capsules, in a tight-packed
monolayer or bilayer on rocks.
References:
Dichotomous Keys:
Kozloff,
1987
General References:
O'Clair
and O'Clair, 1998
Morris
et al., 1980
Kozloff,
1993
Scientific Articles:
General Notes and
Observations: Locations, abundances,
unusual behaviors, etc.:
This species is
uncommon. In many summers of
intertidal study I have found only one and a colleague had found none.

This photo of the anterior end as the animal tries to climb the side
of the bowl shows the nuchal
tentacles and the dorsal and ventral pigmentation.

Authors and Editors of Page:
Dave Cowles (2004): Created original page
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