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Swamp Thing - Ligia olfersii

Swamp Thing - Ligia olfersii
Ft. DeSoto CP, Pinellas County, Florida, USA
August 24, 2007

Images of this individual: tag all
Swamp Thing - Ligia olfersii Swamp Thing - Ligia olfersii Swamp Thing - Ligia olfersii

Moved from Ligia. I agree that this is clearly neither L. exotica nor L. baudiniana, meaning this is most likely L. olfersii, Florida's least common Ligia species. It has only previously been recorded from Key West, Punta rasa, and Virginia Key, but considering how poorly studied isopods are in general, it is not surprising that they exist at more sites in the southern half of the state. Excellent find!

L. olfersii (=L. exotica)?
I agree this is definitley not L. baudiniana nor exotica but whats the status of L. olfersii as a legit species?
SCHMALFUSS consider it a synonym of L. exotica and Jass & Klausmeier don't mention it. Is there another good source I'm overlooking?

According to Schultz 1984 (Terrestrial Isopod Crustaceans from Florida), the two species are frequently confused, but L. olfersii lacks a process on the apex of the propodus of male pereiopod 1. That's my best knowledge on the subject.

Moved from Frass. We don't have many shots of these, and I think yours is worth keeping around, if you don't mind.

I'll second that :o) Was about to leave a comment to the effect this morning, but was torn away from the PC by visitors - darn Easter days ;o(

Like I said below, this one is actually looking somewhat interesting, and I'm not at all sure it'll be the "usual" Ligia exotica- it might just be Ligia baudiniana. I can't be sure (yet) though, as I know neither species IRL and most of the descriptions and drawings I have access to are old(ish) and probably not very accurate (some juveniles/adolescent specimen have been described as separate species at the time). Also, one should also keep in mind that there might also occasionally be another species imported, not yet described from the area.

Someone with more (=any!) experience with these might very well be able to slap a name on this photo immediately. For me, braindead nincompoop as far these are concerned, better crops or other images of head and tail could maybe, possibly help to get a better idea. So if your original is a tad bigger than this or if you have other images you would discard because the "main" part of the animal is out of focus or so, these might still have usable views on the tail end or head/antennae??


Probably not L. exotica or baudiniana
I'm pretty clueless with these as well but I understand that the last abdominal segment for L. exotica or baudiniana should have an angled projection in the middle of the posterior margin, apparently lacking in this example.

I will look

I have added two cropped photos.
Not that great, but may help. I had deleted most of the photos.

Thanks Ken
for the extra images. It doesn't help me right off the bat, but it may in due time. I have been puzzling with the various descriptions of Ligia spp. from the greater area (including north coast of South America) and it's all a tad too hazy for me still, but I'll be sure to pick up more documentation at my next visit to an entomological library.

If you don't mind I'll add some notes on species to be considered and my thoughts about those here later. Or is there a better place for such stuff?

It is OK with me if you add your thoughts here.
If there is a better place, I am sure that someone will advise us.

Moved from ID Request.

Looks like
a Rock Slater (Ligiidae) of some variety--maybe something close to Ligia:

But I'm hardly a crustacean specialist, so let's see what others think.

Yes, should be some Ligia
From what is visible of the shape of the base of the uropods Ligidium may be ruled out. This one is quite interesting looking with the huge greenish eyes and the narrow habitus. How big was this one?

I'm not at all familiar with the Nearctic species, but in general a good close up of the tail end and one of the head, especially a sharp shot of an antenna may help in further ID - if not by me, by someone else at some point (Ferenc?).

Cheers, Arp

Thanks for the direction.
I will look for this again this year, and see if I can get better photos and size estimate.

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