Like all Epicaridean
isopods, this species is parasitic on other crustaceans. Epicaridean
females tend to be of distorted shape with most appendages
or absent, while the males, which usually are found on the females, are
small and symmetrical. Bopyroides
hippolytes has separate sexes at least as adults, and the
smaller and more symmetrical than is the female (characteristic of
They are ectoparasitic in
chambers of shrimps of families Hippolytidae
Females are less asymmetrical than in some other bopyrids (at least
are still recognizable as isopods), with all pereonites
distinct, with 5 pairs of nearly equal oostegites
and 7 pairs of pereopods.
The female usually has 6 distinct pleonites
but these either lack or have only rudimentary
lateral plates. Her pleopods
are also missing or reduced to tubercles.
She has no uropods.
Her brood pouch is open (the oostegites
do not close over each other to form a closed chamber). The pleonites
of the male are fused.
Common name(s): Shrimp parasitic isopod
|A female Bopyroides
about 2 cm long, from the gill chamber of the shrimp Pandalopsis
|(Photo by Dave Cowles,
July 2008 )
How to Distinguish from
pugettensis lives on shrimp in family Crangonidae, and the
has well developed pleopods
Other bopyrids are found on thalassinids,
crabs, or on the dorsal side of the thorax or underside of
Ocean, Bering Sea, Arctic Canada, Greenland, eastern North America,
and Britain. On our coast found down to southern California
Intertidal and subtidal.
This isopod is parasitic
on several families of shrimp, especially members of families Hippolytidae
(such as Heptacarpus
brevirostris) and family Pandalidae
(such as Pandalopsis
dispar and Pandalus jordani),
but not on members of family Crangonidae.
Isopods of family Bopyridae live parasitically on the gills of other
such as shrimp. Typically a large female and a smaller male
together on the same individual (photo).
Usually they parasitize only one side of the host--rarely is a shrimp
on both sides by bopyrids. The females are usually
photo above), while the males are symmetrical (photo).
They seem to enter the shrimp early in the shrimp's life and remain
molts. In Pandalopsis
dispar they appear to retard growth and delay
sex change in
the host shrimp. Bopyrids develop to young larvae within the
formed by her oostegites.
In this individual, the mother's ventral side was pressed against the medial
surface of the gill cover instead of against the gill itself (photo).
did not overlap, but simply formed a wall around the eggs while the
gill cover formed the floor of the chamber the eggs were
When I removed the female from the gill chamber her eggs mostly spilled
out because they were not fully enclosed by the ooostegites.
The first larval stage is 2-3.5 mm long and is called an
It has six free pereonites,
each of which bears a pair of subchelate
which it uses to attach to an intermediate planktonic host such as a
On that host it molts into a "microniscus" or "microniscum" larva, then
later to a "cryptoniscum" or "cryptoniscus", which is up to 7 mm long
has a 7th pereonite.
At this stage it releases from the intermediate host, becomes benthic,
and finds its final crustacean host. Within the host it
into either a large, asymmetrical female or into a smaller, symmetrical
male (apparently it can become either sex). The adult form is
Kozloff, 1987, 1996
Smith and Carlton, 1975
Lamb and Hanby, 2005
O'Clair and O'Clair, 1998
General Notes and
abundances, unusual behaviors:
This view shows the bopyrid parasite within the right gill
the host, Pandalopsis
(The large bubble-like structure next to the abdomen is a part of the
A closeup of the parasite within the gill chamber, seen from the dorsal
view of the host. The host's head is to the left in this
|Below are ventral views of Bopyroides
hippolytes, both within the host gill chamber (left) and
|A view of Bopyroides
from the outside through the host's carapace
wall of the gill chamber. Notice the overall yellowish
which is apparently due to the large cluster of eggs the female is
under her thorax against the carapace
wall. The host's carapace
wall curves smoothly out around the bopyrid, probably indicating that
bopyrid was present at the last molt of the host when the host carapace
was soft and pliable. Note, however, the indentation on the
wall, which also seems to be permanent, and the slight injury to the
|This is a ventral view of the same individual as above
and at left.
The circle of large oostegites
can be seen around the edges of the female's thorax, but as can be
do not fold together and overlap in the middle. Instead, the
side of the mother with a number of remaining eggs can be seen within
circle of oostegites.
This surface was pressed against the inner surface of the host's carapace
within the gill chamber while in the host. Many eggs spilled
when I removed the female from the host; a few of which can be seen
around in this view. Notice also the small, symmetrical male
to the underside of the female's abdomen.
This view shows the diminutive male, 5-8 mm long, which is clinging
to the ventral abdomen of the female with its head against the female's
Notice that the male has distinct eyes, and its pleonites
following photos show a Bopyroides hippolytes on a Pandalopsis dispar
shrimp captured from 110-200 m depth in the San Juan Channel, 2010.
Photos by Dave Cowles
|In the photo above the parasite can be seen making a
sharp bulge in the host shrimp's carapace.
the carapace shows how snugly the parasite is packed into the branchial
chamber. The surface exposed here would have been in contact
the host's gills.
|The female is large, with a reduced-size male hanging
onto the abdomen (to the left).
Authors and Editors of Page:
Dave Cowles (2008): Created original page
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