As with all caprellid
amphipods, the pereon
has only 6 visible pereonites,
some of which have only vestigialpereopods;
and the body is slender and sticklike, somewhat resembling a praying
pilimana has gnathopods
but no gills on pereonites
1 and 2 (photo).
flat, leaflike gills and vestigialpereopods
3 and 4 (photo).
3 and 4 have only 1 article
has a palp.
The second antennae have long setae
on the longer articles,
and the next to the last article
of antenna 2 is about 6x as long as wide and has setae
about 2x as long as the article
is wide (photo).
Tritella pilimana Mayer, 1890
Common name(s): Skeleton Shrimp
|Tritella pilimana found on eelgrass
on March Point, Padilla
Bay June 2007. Total length not including antennae = 2.4 cm.
|(Photo by: Dave Cowles
How to Distinguish from
laevis has a next-to-last article
of antenna 2 only 4x as long as wide and its setae are not much longer
than the article
is wide. Mayerella
has 2 articles
on its vestigialpereopods
3 and 4.
Can be found on eelgrass
amphipods such as this species appear to be fearsome predators for
size. They hold onto substrates such as eelgrass or hydroids
their posterior appendages and wave their bodies around looking for
to grab. They can move from place to place by grabbing the
with their anterior gnathopods, then loosening their posterior legs and
moving them up to the new object to reattach..
and Carlton, 1975
General Notes and
abundances, unusual behaviors:
This view shows the same individual from the dorsal aspect.
In this ventral view of the anterior half of the body, the gnathopods
present at the anterior end of pereonite 1 and at the posterior end of
pereonite 2 are visible. It has no gills on either of these
In this ventral view of the posterior half of the body (head is to
right), the flat leaflike gills can be seen on midsections of
3 and 4 (part of the second gnathopods can be seen at the right on
2). Ahead of each gill is a small bump which is the vestigial
for that pereonite. Pereonites 5-7 on the left have
pereopods which act as claws to attach the animal to the eelgrass.
This view shows pereonites 3 and 4 closer up (the end of pereonite
2 with ghathopod 2 is visible to the right). On each of
3 and 4 a small, 1-article vestigial pereopod can be seen projecting
near the front of the article and a leaflike gill projects from farther
back. Note the large dorsal, forward-directed spine on both
3 and 4.
In this lateral view of the head and antennae 2, the long setae on
antennae 2 can be seen. The next to last article of antenna 2
about 6x as long as wide and has setae at least 2x as long as the
Notice also the large, single dorsal spine on the head and the small
first gnathopods at the anterior end of pereonite 1. The
antennae are extending upward out of the picture.
This dorsal view of the head shows more clearly the first and second
|These are the first gnathopods, directly behind the
that they are subchelate and the carpus and propodus are enlarged.
||This is a view of the right second gnathopod.
Notice that it
is also subchelate but the propodus is not particularly enlarged.
female is carrying a clutch of eggs enclosed within flap-like oostegites
on the ventral side of her thorax.
Her total length is about 1 cm. Found on Ulva
in Padilla Bay, June 21, 2012. Photo by Dave Cowles.
Authors and Editors of Page:
Dave Cowles (2007): Created original page
Jonathan Cowles (2007): Updated page with CSS