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Some Kind of Isopod? - Pentidotea aculeata

Some Kind of Isopod? - Pentidotea aculeata
La Jolla , San Diego County, California, USA
January 1, 2014
Size: 1.5 to 2 cm
Found at the tide pools on a rock with algae at low tide. The photos were taken on a jacket for better light and focus.

Images of this individual: tag all
Some Kind of Isopod? - Pentidotea aculeata Some Kind of Isopod? - Pentidotea aculeata

Moved from ID Request.

I was just about to move these (not to species, though) when I saw Chris's ID. Hope he doesn't mind too much that I went ahead and created the page. :)

Images cropped for placement.

Thanks Ken
for the new guide page :)

These are such fantastic arthropods and very underrepresented here on BG so it's always great to see some new ones getting posted. Great addition to the guide.

Often the keys require a good view of the maxilliped for many species - which is difficult to do without a microscope - but fortunately for this one we lucked out and got a species that can be keyed out using macroscopic features.

Keys confidently to Pentidotea aculeata
with the keys from The Marine Isopod Crustaceans by M. A. Schultz. Matches the diagram perfectly as well, though there does not appear to be a single photo on the internet to compare to (but compare to the illustration on here). Notable features include the pleon with posterior margin strongly produced (probably the most visible feature), a convex body margin with pleon noticeablely narrower than the widest parts of the body , and lateral ends of peraeonal segments slightly to moderately seperated at the ends - all of which match your specimen perfectly. The given range is Central to Southern California tidepools, length given is up to 23mm.

Excellent find.

Maybe a Valviferan?
Looks a lot like an aquatic isopod of the Valvifera family. No idea what genus or species this could be.

Idoteadae maybe

this is my best guess, but I have never seen a red one.

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