Pandalus goniurus
Stimpson, 1860
Common name(s): Humpy shrimp, flexed pandalid
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Synonyms: Pandalus
dapifer |
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Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
Subclass Eumalacostraca
Superorder Eucarida
Order Decapoda
Suborder Pleocyemata
Superfamily Pandaloidea
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Pandalus
goniurus, nearly
8 cm long from telson
tip to rostrum tip. Captured by otter trawl at 75 m
depth, San
Juan Channel. Note the bend in the abdomen, which is more
prominent
than in most Pandalid shrimp. |
(Photo by: Dave Cowles,m
July 2008 ) |
Description:
As with other shrimp
in Family Pandalidae, this shrimp has no exopodites
on the pereopods,
pereopod
1 is not subchelate,
and the carpus
of pereopod
2 is multiarticulated (divided up into many subunits--7 or
more).
The rostrum
is prominent, with movable dorsal spines. Pandalus
goniurus has first antennae about as long as the carapace
(the long antennae above are the second antennae). Abdominal
segment
3 is laterally compressed and has a median lobe or spine (photo).
Abdominal segment 4 does not have a mid-dorsal sharp spine on the
posterior
margin (photo) but does have
a small ventral spine
on the pleuron.
The fifth abdominal segment has a well-developed posterolateral
spine.
The telson
has a blunt tip and 5-7 dorsolateral spines (photo).
The uropods
are longer than the telson.
The distal half of the lamella
of the antennal
scale is at least as wide as the spine
(photo), but the spine
is slightly longer than the lamella.
The distal half of the rostrum
angles upward, does not have dorsal spines (photo)
and is bifid
(has two points). The shrimp's overall color is translucent
white
with fine red stripes and small red dots. The fine red
stripes on
the abdomen angle upward toward the rear. The outer margin of
the
antennal
scale is red. The telson
and uropods
have yellow spots near their bases (photo).
The eyes are fairly large. The left pereopod
2 is longer and thinner than the right pereopod
2 and has more annulations on the multiarticulated carpus
(51-54 vs 18-20). Males total length to about 6.2 cm, females
to
7.8 cm.
How to Distinguish from
Similar Species:
The laterally compressed, "humpy" third abdominal segment with the
median
dorsal lobe, as well as the distinctive abdominal striping help
distinguish
this species from other Pandalids. Pandalus
danae has diagonal abdominal stripes but they
are coarser and
angle downward toward the back. Pandalus stenolepus
has a humped back and abdominal
stripes which angle upwards toward the back like this species does, but
it also has large, dark red spots and blue dots.
Geographical
Range: Off Japan, Siberia,
Alaska (Bering Sea), British Columbia, down to Puget Sound.
Depth Range:
Subtidal to 450 m
Habitat:
Sandy and muddy bottoms
Biology/Natural History:
This species captures its prey between its legs before feeding on
it.
It is a protandrous hermaphrodite (male first, then female later in
life).
It probably is a male its first year, becomes female the second year
and
lays eggs, then dies. Eggs are seen from late November to
April.
Predators include sand sole.
References:
Dichotomous Keys:
Kozloff,
1987, 1996
General References:
Butler,
1980
Jensen,
1995
Lamb
and Hanby, 2005
Scientific Articles:
Web sites:
General Notes and
Observations: Locations,
abundances, unusual behaviors:
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The rostrum
has movable dorsal spines on the proximal half but none on the distal
half.
The distal half angles upward. |
The distal half of the lamella
of the antennal
scale is at least as wide as the spine,
but the spine
is longer than the lamella
and projects beyond it. There is red on the outer margin of
the antennal
scale. |
These two views of the head show
characteristics of the
rostrum
and of the antennal
scale. |
Pandalus
goniurus abdomen
side view |
Pandalus
goniurus abdomen
dorsal view |
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These views of the abdomen show the
slightly compressed
nature of the high lobe on the 3rd abdominal segment. Note
also that
there is no mid-dorsal sharp spine on the ventral margin of segment 4,
but there is a small spine on the posteroventral margin of that segment
(on the back tip of the pleuron). The fifth segment has a
large posteroventral
spine. |
The telson
has 5-7 lateral spines along the dorsal side and a blunt tip.
Notice
that the spots near the base are yellowish. The uropods
are longer than the telson.
Authors and Editors of Page:
Dave Cowles (2008): Created original page
CSS coding for page developed by Jonathan Cowles (2007)
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