Ligidium blueridgensis is a species of Woodlouse in the family Ligiidae (Rock slaters) described from the Blue Ridge Mountains in northern Georgia (USA).
Similar species: Brood Pouch Crustaceans
By Flown Kimmerling
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Uploaded Jan 2, 2021. Captured Jan 1, 2021 15:15 in 227 Oakman Rd NE, Oakman, GA 30732, USA.
comments (34)
Thought this one might interest you! Posted 4 years ago, modified 4 years ago
I was just logging in to ask where this was, but you've geotagged it meanwhile :o)
Ligidium is correct, but beyond that I would need to dig up the scarce documentation I have on American woodlice ... will try to find it later tonight and see what I have on Nearctic Ligidiums Posted 4 years ago
From what I'm seeing on iNaturalist and other sites, not many people have a clue as to a species-level ID on the Ligidium in the Southeast US. Posted 4 years ago, modified 4 years ago
Jass & Klausmeier published a lot on Woodlice from Wisconsin and never seem to have found a Ligidium there, but they did publish more on the Americas in general, of which two documents that are quite helpful:
Jass, J.; Klausmeier, B. (2000) Endemics and Immigrants: North American Terrestrial Isopods (Isopoda, Oniscidea) North of Mexico. - Crustaceana, Vol.73(7), pp.771-799.
https://doi.org/10.1163/156854000504804
https://www.jstor.org/stable/20106344
Jass, J.; Klausmeier, B. (2001) Terrestrial isopod (Crustacea: Isopoda) atlas for Canada, Alaska, and the contiguous United States. - Milwaukee Public Museum, Contributions in Biology and Geology, vol.95, pp1–105.
https://research.nhm.org/pdfs/4571/4571.pdf
They classify Woodlice in general terms as native or immigrant, due to the fact that many of the most wide spread species in North America seem to be European (mostly) imports, with basically some coastal and cave species classifying as originally native. One criterion they used is the range of the species and due to this, one species, with an exceptionally wide range, both eastern and western, falls into their definition of "immigrant", but it is clearly a native American species: Ligidium elrodii. It is virtually impossible for any Ligidium to be "introduced" to the Americas by humans (historically) as these would simply not survive the trip - they are way too dependant on a very wet habitat. So the "immigrant" term might be understood here as something like: "probably has spread from its original range in America to other parts" or some such. In fact, it's probably a bit of a problematic "unit"/species, as many "sub-species" have been described, usually from quite isolated habitats in local caves. These are generally said to be near impossible to ID form general appearance, but male genitalia do give rise to separating them at least as subspecies. The question is, of course, if these are truly subspecies (as in: they would cross-breed with each other) but from what I have found so far no such experiments, nor genetic analysis have been tried (but maybe I just didn't find/read it if it has).
Posted 4 years ago, modified 4 years ago
Anyway, from your neck of the woods only a few candidates within the North American Ligiidae would need to be seriously considered:
Ligidium elrodii (Packard, 1873)
- L. elrodii chatoogaensis Schultz, 1970
- L. elrodii hancockensis Schultz, 1970
Ligidium blueridgensis Schultz, 1964
Ligidium elrodii s.l. has historically been identified as Ligidium longicaudatum or even Ligidium hypnorum (an European species) and mostly all older publications simply are not precise enough to use as valid descriptions to separate any Ligidium from another. Only by study of the type specimen, the taxonomic confusion on most described species has at some point been solved. In this respect the two publications by Schultz (1964, 1970) that describe the new (sub)species are the ones to use for solid ID-characters. All other keys generally will let you separate any Ligidium from all other genera, but the characters are never enough to truly ID the species, which is fine as long as you can rightfully assume that only L. elrodii is present in a certain region/state that the key is designed to service.
Schultz, G. A. (1964) Two additional data on terrestrial isopod crustaceans: Ligidium blueridgensis, sp. nov., from Georgia and a North Carolina cave location for Miktoniscus linearis (Patience, 1908). - Journal of the Elisha Mitchell Scientific Society, Vol.80(2), pp.90-94.
https://dc.lib.unc.edu/cdm/ref/collection/jncas/id/2528
https://www.jstor.org/stable/24334860
Schultz, G. A. (1970) Descriptions of new subspecies of Ligidium elrodii (Packard) comb, nov. with notes on other isopod crustaceans from caves in North America (Oniscoidea). - American Midland Naturalist, vol.84(1), pp.36-45.
https://doi.org/10.2307/2423724
https://www.jstor.org/stable/2423724
The (sub)species are mostly distinguished on the morphology of the male pleopods (requiring _very_ hi res underside images, but frankly really a microscope) and some other minute details in hair tufts etc. BUT also on the count of the number of segments in the antennal flagellum(!) For the microscopic details a male specimen would need to be collected. Of course I would be happy to do the examination, but you may be able to find sources closer to home for that. That leaves the count of the flagellum segments as the only "indicative" feature for photo ID. Posted 4 years ago, modified 4 years ago
Summary of the key points in the descriptions by Schultz and from other publications:
L. elrodii elrodii has been described and is known from similar habitats as your specimen, it is the most common species of Ligidium and the most likely to be encountered in the eastern US. That said, I have not clearly read about any published records of L.e.elrodii from GA,NC,TN or AL, just the records/descriptions of the subspecies found there. Unclear to me if the nominal (non-cave) species is truly present in the region.
Anyway: The count of flagellum segments is mostly given as 13, on occasion as 14.
L.e. chatoogaensis and hancockensis are both described as cave subspecies - not likely to be found in the habitat of your specimen.
L.e.chatoogaensis from Blowing Spring Cave, 2.5 miles NE Cloudland, Chattooga Co., Georgia. - It should have 13 flagellar articles, much like L.e.e.
L.e. hancockensis from Cantwell Valley Cave, Hancock Co., Tennessee. - It is said to have 12 or 13 flagellar articles.
Ligidium blueridgensis is described from a habitat much like where you found your specimen and quite close to where you found it to boot (in the grand scheme of things). It is described as having 16 flagellar articles.
Looking at your image, the left antenna is in a perspective that would allow counting (somewhat). I count 13 reflections, that I take to be globular end caps of the larger articles. Beyond that there is quite a bit of flagellum left that should harbour at least two more articles of decreasing size, quite possibly even three (to fill the full 16 for blueridgensis).
To conclude:
- Habitat should fit for L.blueridgensis or L.e.elrodii
- Of L.blueridgensis we can be sure that it is known from the region. For L.e.elrodii I didn't encounter conclusive published records.
- The antennal flagellum (15-16 articles?) seems to strongly suggest L.blueridgensis rather than L.e.e.
It would be good to see better shots/crops of the flagellum of either left or right antenna and/or better yet a male specimen to eliminate all doubt, but I do think that even from this one image it is fair to assume Ligidium blueridgensis is clearly the most likely candidate. Posted 4 years ago
https://dc.lib.unc.edu/cdm/ref/collection/jncas/id/2528 Posted 4 years ago
As you had mentioned iNaturalist above somewhere, I had a quick look at some of the discussions/IDs with a few of the Ligidium observations there. I never used the system, but I can't help getting the feeling that some of the "ID"s given are basically something like: "Oh, someone has given a (unsubstantiated) ID - let me yell the same name and I'll get some 'credits' or 'esteem'" or some such?!? Is there some credit or reputation system in place there for giving IDs, even if the same ID has already been issued? It seems a bit strange ... That, plus the "unsubstantiated" (more often than otherwise) has me worried about what to think of the IDs. One "elrodii" from eastern NC was "identified" by it being a more eastern location than any of the other (sub)species are known from. Well, at least that is _some_ substantiation, and that is a good thing, because it puts the ID into perspective. With so little (published) records beyond the few specimen from the original description I would be hesitative to go on location as a sole criterion.
Best would be if people could be encouraged to collect a male and properly look at it under a microscope, but second best would clearly be to raise awareness that at least a sharp, hi res image of the flagellum could go a long way to giving something to go on. Posted 4 years ago
Arp, the problem you describe (baseless mass "I agree" identifications) are discussed at length here:
https://forum.inaturalist.org/t/overzealous-identification/5975/19
It seems a small minority is doing this at fairly large scale, probably for the honor to be in the leaderboard. It creates real damage as this behavior leads to incorrect "research grade" observations, which then make it to GBIF, polluting data used by real researchers.
This is possible because there is no expert filter. And as the thread shows, they have good reasons for that. An expert filter would work fine for popular categories like birds, yet in most other categories, there simply aren't enough experts to deal with the enormous volume of observations. If an expert ID was required to make an ID formal, very little would get identified. Hence the more open consensus approach, where experts do their best to clean up afterwards.
It's a somewhat understandable compromise, given the situation at hand. The part I don't understand is their softness in dealing with the extreme cases. We're not talking about an amateur/beginner making an honest mistake. We need to be almost infinitely empathetic to honest mistakes, and assume good intent.
This is different. These are individuals creating massive damage to a platform for vanity reasons only. There's no benefit of the doubt in these cases. Yet nobody stops them because they don't want to discourage them or upset them. I find that a strangely soft policy, but that could be just me.
The above is probably/hopefully not the standard behavior, but I imagine a possible solution is to introduce a middle ground "semi-expert". Everybody would start with it, even amateurs (assume good intent), yet when proven you're just consistently guessing or misbehaving, take the right away. It's reasonable to expect of people to not constantly pollute data with nonsense.
A stronger measure is to take away the leaderboard altogether, as that is the main incentive for the abusers. Yet this could hurt experts with good intent, whom are doing work with very little reward, and now get even less satisfaction out of it.
In any case, my respect for experts like you and Lisa doing this thankless uphill work is infinite. Posted 4 years ago
It's a "problem" on all platforms that strive to provide good data. I've read some of the thread that Ferdy referenced. One of the Hospers brothers made a (good/fair) point that on observation.org we simply don't have enough (true) experts for all the (niche) groups. On waarneming.nl (the Dutch parent to observation.org) this problem has been quickly getting less of an issue as more and more "über"-experts have been coming on board over the past few years as momentum of the site increases, in part due to it often being referenced in research papers.
I think, from the little that I read on the iNaturalist forum thread, that the site has two things confused:
1) Identification
2) The confirmation of that ID by an expert, for it to be used for research purposes.
To get a (fair/proper/likely) name on an observation the "crowd consensus" approach is fantastic. To value this as "Research grade" is downright silly.
Frankly, I'm shocked to read that GBIF accepts that as is. On the other hand, any researcher that needs to use records for research should probably "validate" each and every record personally or create a network of trust with trusted observers that follow a fixed protocol for observing/counting etc.
On waarneming.nl we have agreements between the folk with "validation access" for certain groups that we leave some taxa untouched to be handled by one expert only who wishes to use the "validated" observations for upcoming publications.
In the end it is all about trust. If I go to a museum and look at the ID-tags under a specimen I also need to decide for myself if I trust the name of the identifier or do the ID over again myself (if I'm capable of that) or discard the record as "questionable".
It is good to have a system to involve the crowd, but it should be combined with a system of trust based on real life reputation, not counting/averaging points-gathering "trust" - that is, if you want to claim "Research Grade".
My 2 cents Posted 4 years ago, modified 4 years ago
iNaturalist seems on an insane growth spike, almost doubling in a year, so surely this amplifies underlying problems and challenges. It's an interesting dynamic. The very low barrier to entry (point smartphone at thing and be done) creates massive amounts of observations, which in itself is good. Quantity can be useful and there's the benefit of engaging amateurs in the natural world. Yet the other side of the coin is that data quality challenges get bigger and bigger.
I don't think there's a simple solution for it, just something we have to live with and make the best of it. Interesting that observation.org does bring in more (or better) experts. I would expect this same effect on iNat, which is much more known internationally.
Posted 4 years ago
For the (worldwide) sister site observation.org influx of experts and observers is still slower.
Should be good/interesting to see how this "gaining momentum and attracting experts" thing pans out for iNaturalist and other colleague sites over the coming period. Posted 4 years ago
On a more serious note, I do count our blessings in this discussion. A decade ago, most of this did not exist. Now we have several massive platforms, some excellent verticals (eBird, Mushroomobserver, Bugguide, etc) and a suite of very useful identification apps, and so much more. Posted 4 years ago, modified 4 years ago
I'm ever grateful for what we have at our disposals. Communities like these (including JungleDragon) have helped me discover my true passion (and literally saved my life). The friends I have made are also invaluable <3 Posted 4 years ago
Undesired behavior should be corrected. First with understanding and the gentle hand. If that doesn't work, the firm hand. You can't let it linger as it destroys and undoes the work of good actors. IMHO. Posted 4 years ago
So the above part is understandable, light or no curation due to the scale of data.
Extreme misuse, however, should be clear cut. Somebody should step in. In the example from the iNat discussion, some idiot marks 57,000(!!!) observations in this "me too, I agree" way. Without even studying the photo at all, which often is just a black dot in the sky, supposedly a bird.
Am I the only one thinking of such person as a data vandal? I would hit that ban button immediately, and then do it again to be sure. I'd have zero second thoughts about it. Good riddance.
Not over there. Community members emphasize staying kind and constructive to correct the behavior.
They're kinder than me, but I believe there's a point where you're too kind.
Posted 4 years ago
To use an "Agree"-button for that is asking for it. If anything of that order, then it should be a "Disagree"-button that gives you credits, but only if you can make clear why and suggest another ID. Lots of hooks and possibilities to shoot yourself in the foot with systems like that, I'm afraid ... Posted 4 years ago, modified 4 years ago
All easier said than done, of course, but for the extreme cases my solution would be quite simple. "Goodbye". Posted 4 years ago