Talk:Potamon fluviatile

refs for freshwater crabs in other major cities
Hi, these are a few references for freshwater crabs in major cities: Cairo: http://www.landesmuseum.at/pdf_frei_remote/ANNA_99B_0571-0589.pdf Johannesburg (Germiston): http://www.sciencedirect.com/science/article/pii/S0147651398916992 Depending on whether or not one considers Eriocheir sinensis 'freshwater', London, Hamburg, etc.: http://www.europe-aliens.org/pdf/Eriocheir_sinensis.pdf (and many others). I found the statement in National Geographic highly bizarre, could it be that they only meant Potamon fluviatile? I have never seen this species so I don't know how common it is. The two Potamonautes spp. are extremely common at the two locations. Rainbowwrasse (talk) 10:13, 23 August 2011 (UTC)


 * Without necessarily defending the statement reproduced in the article, I can imagine how the authors might justify it. The presence of crabs in the Nile at Cairo isn't quite the same as having them close up among the human population, as they are in Rome. The Thames in London is entirely tidal, as is the Elbe in Hamburg, so they could easily be discounted from "freshwater" if one was using a strict definition. I'm not even sure that Cumberlidge (1997) [the first link above] claims that Potamonautes niloticus is present in the city of Cairo – might the text "Cairo" and "Assuan" not refer to Cairo Governorate and Aswan Governorate? In any case, we have a satisfactorily cited claim that Potamon fluviatile is the only freshwater crab in the centre of a large city, and no reference that explicitly says it isn't. Any interpretation that we make based on other sources could be seen as original research. --Stemonitis (talk) 10:17, 23 August 2011 (UTC)
 * I probably would not count mitten crabs either, but there is no reason to believe that 'Cairo' was meant as 'Cairo Governorate'. The governorates are referred to as such, whereas the city is just called 'Cairo' (and is far more urbanized than Rome). We might more easily assume that 'freshwater crabs' in the NG piece only refers to Potamon fluviatile. One of the sources also lists further major cities such as Yaounde and Nairobi as localities. The problem with the claim is that it is simply so bizarre that it's difficult to find a source that explicitly says it isn't true; it's similarly difficult finding a source stating that pigs cannot fly. Freshwater crabs are so widespread in the waterways of (at least African, can't speak for others) cities that the best one can hope for is a passing mention that someone collected them there; it's very unlikely that someone would explicitly state 'freshwater crabs are common in X'. I do not see how interpreting (if on can call it that) the fact that someone found crabs in, say, Cairo or Yaounde as an indication that they must therefore occur in those cities is original research. Also, I am not saying that the article should say that freshwater crabs are commonly found in cities, I am just saying that the the statement that out of all the cities in the world, only Rome has freshwater crabs should be left out (or possibly change 'freshwater crabs' to P fluviatile). I know that prima facie this looks like the 'verifiability, not truth' criterion, but this is a relatively minor point and so obviously false that I think it would be better to just leave it out. Also, P. fluviatile is known as the freshwater crab in Italian (Il granchio d’acqua dolce), so it is quite likely that only this species was originally meant. I therefore think that the NG source is not necessarily all that precise. That is my opinion, but in a way it's your article, so I am not going to challenge it (great job on all the invertebrate articles, BTW, you seem to be responsible for a lot of them!). Rainbowwrasse (talk) 18:04, 23 August 2011 (UTC)


 * I can't believe they would mean just P. fluviatile and state "freshwater crabs". They must just be wrong. I think I do now agree that it's best to simply take it out; I'll do that now. --Stemonitis (talk) 18:41, 23 August 2011 (UTC)