09 February 2016

The crayfish / crawfish / crawdad war II

A couple of years ago, some fun dialect maps were making the rounds on the Internet, which I blogged about because one of the questions was about what people call freshwater crustaceans that look like small lobsters.

Those maps were based on the Harvard dialect survey, which ended 2003. This is now being followed by the Cambridge dialect survey, which started 2007, and what people call Astacidea is again one of the questions.

The map is interesting to check out. I think “lobster” looks far more common in the map than in the data, probably because of the layering of the data points.

Interestingly, the gap in use between “crayfish” and “crawfish” widened between the Harvard and Cambridge surveys. But in both surveys, “crayfish” is more northeast, “crawdad” is midwestern, and “crawfish” is southern. I wonder how “fish” metamorphosed into “dad” in the central U.S.

Related posts

The crayfish / crawfish / crawdad war

External links

Harvard survey: Asticidea map
Cambridge survey: Astacidea map

02 February 2016


The world hotspot for crayfish species, by a long, long way, is the southeastern United States (map from Richman et al. 2015).

The southeastern U.S. is also notable for relatively large populations of African-Americans.

You might think that given the overlap in these two maps, that there would be expertise in the African-American community about crayfish. But I am struggling to think of any African-American scientist who has studied crayfish. Who am I missing?

This also points to crayfish being a great entry point to introduce African-Americans to topics like biology and conservation.


Richman, NI, Böhm, M, Adams, SB, Alvarez, F, Bergey, EA, Bunn, JJS, Burnham, Q, Cordeiro, J, Coughran, J, Crandall, KA, Dawkins, KL, Distefano, RJ, Doran, NE, Edsman, L, Eversole, AG, Füreder, L, Furse, JM, Gherardi, F, Hamr, P, Holdich, DM, Horwitz, P, Johnston, K, Jones, CM, Jones, JPG, Jones, RL, Jones, TG, Kawai, T, Lawler, S, López-Mejía, M, Miller, RM, Pedraza-Lara, C, Reynolds, JD, Richardson, AMM, Schultz, MB, Schuster, GA, Sibley, PJ, Souty-Grosset, C, Taylor, CA, Thoma, RF, Walls, J, Walsh, TS, Collen, B. 2015. Multiple drivers of decline in the global status of freshwater crayfish (Decapoda: Astacidea). Philosophical Transactions of the Royal Society of London B 370: 20140060.

External link

African-American History Month

Map of African-American distribution from here.

01 February 2016

Marmorkrebs homepage moved

The Marmorkrebs.org home page has migrated over to a new institutional server. The old site will be up for a while until I get a redirect notice up, but it will eventually close as website support for my previous institution (The University of Texas-Pan American) transitions to my new one (The University of Texas Rio Grande Valley).

If you visit the site by a directly typing in the URL into a browser, you should see no difference.

If you  bookmarked the homepage, take a moment to check that it directs to the correct URL:


You can let me know if there are any problems by emailing me at zen.faulkes@utrgv.edu.

26 January 2016

Risk assessment, Irish style

In my tooling around the Internet for Marmorkrebs related research, I found this risk assessment for Marmorkrebs as a potential non-indigenous crayfish in Ireland. It seems to be an extremely thorough document.

Marmorkrebs are not the only crayfish assessed, either. Noble crayfish (Astacus astacus), Turkish crayfish (A. leptodactylus), spiny-cheek crayfish (Orconectes limosus), signal crayfish (Pacifastacus leniusculus), and the champion non-indigenous crayfish, the Louisiana red swamp crayfish (Procambarus clarkii) all get similarly extensive review.

External links

Non-native Species Risk Assessment for Ireland

25 January 2016

Sell your Marmorkrebs, Tennesseans

A week ago, I reported stumbling upon  information indicating that Marmorkrebs had been designated “Class V Wildlife” (basically, zoos only) in Tennessee. I can now confirm that this is correct. This effectively means that keeping Marmorkrebs as pets is now illegal in Tennessee.

Trying to track this down required a little effort. As I mentioned before, my initial Google searches failed miserably. Twitter to the rescue!

The Tennessee Wildlife Resources Agency has a Twitter account. They replied to my tweet, and gave me a phone number to try. It took several tries over multiple days to get a person instead of a voice message. When I did get through, I got another phone number to try, but luckily, got an answer to on the first call. And the person I spoke to was able to confirm that Marmorkrebs was added to Tennessee’s list of Class V wildlife last October.

People have kept Marmorkrebs in Tennessee: I found some owners discussing their pets in a previous paper (Faulkes 2013; data here). But I wonder how someone who wants to be a responsible, law-abiding pet owner is supposed to learn about this new regulation. I specifically watch for news about Marmorkrebs like a hawk, and I missed this item for three months. Then it took me almost a week of phone tag to track down someone who could confirm it. The Tennessee officials I spoke to on the phone were super helpful, but still, I put in considerable effort to learn this information. Not everyone will have my obsessive motivation.


Faulkes Z. 2013. How much is that crayfish in the window? Online monitoring of Marmorkrebs, Procambarus fallax f. virginalis (Hagen, 1870) in the North American pet trade. Freshwater Crayfish 19(1): 39-44. http://dx.doi.org/10.5869/fc.2013.v19.039

Supplemental info: Faulkes Z. 2013. Online monitoring of Marmorkrebs in the North American pet trade. figshare. http://dx.doi.org/10.6084/m9.figshare.645344

Related posts

Owning Marmorkrebs in Tennessee might just be illegal now

20 January 2016

Martin and colleagues, 2016

Martin P, Thonagel S, Scholtz G. 2015. The parthenogenetic Marmorkrebs (Malacostraca: Decapoda: Cambaridae) is a triploid organism. Journal of Zoological Systematics and Evolutionary Research 54(1): 13–21. http://dx.doi.org/10.1111/jzs.12114


There is a close association between parthenogenesis and polyploidy. For this reason, we undertook a karyological analysis to test whether the parthenogenetic Marmorkrebs, Procambarus fallax forma virginalis, possesses an enlarged set of chromosomes. For this purpose, we karyotyped the Marmorkrebs, the sexual form of P. fallax (together called P. fallax complex), and the closely related species P. alleni. The latter shows 94 chromosomes in the haploid condition. In contrast to this, we found a haploid set of 92 chromosomes in individuals of the P. fallax complex. However, in mitotic metaphases the sexual form shows 184 chromosomes, whereas the Marmorkrebs possesses 276 chromosomes. Hence, the parthenogenetic Marmorkrebs reveals a triple amount of the haploid chromosome number. In addition, we detected a strikingly large subtelocentric chromosome which appears once in haploid and twice in diploid cells of sexual individuals of the P. fallax complex. In the parthenogenetic Marmorkrebs, this prominent chromosome occurs thrice. All this clearly reveals that the Marmorkrebs is a triploid organism. The applicability of the used methods, the significance of polyploidy in evolution of Decapoda, putative pathways to parthenogenetic triploidy, a possible hybrid origin and the scientific and ecological consequences of an increased chromosome set in Marmorkrebs are discussed.

Keywords: apomictic thelytoky • autopolyploid • allopolyploid • whole-genome duplication • elongation factor 2 • invasive species

19 January 2016

Owning Marmorkrebs in Tennessee might just be illegal now

I ran across a notice that Marmorkrebs have been added to Tennessee’s list of “Class V wildlife.” (Update, 25 January 2016: the link is already busted.) This is the entirety of the text I have right now (my emphasis and sics)

TN Wildlife Resources Agency
Amends Section 1160-01-18-03 of Tennessee Administrative Code to add the African clawed frog (Xenopus lacvis) (sic) and Marbled crayfish (Procaburus (sic) fallax f. virginalis) to the list of species classified as Class V Wildlife.

It would not surprise me if Marmorkrebs were the subject of legislation in Tennessee, because that state is near, if not the center, of the world’s hotspot for crayfish biodiversity. Non-indigenous crayfish could cause a large number of problems for indigenous crayfish species in Tenessee.

I wanted to confirm this, but, somewhat to my surprise, my initial tooling around in Tennessee government websites yielded nothing. Even with what appears to be a fairly detailed description of the source of information, I can’t find it.

It took several tries to even find a definition of what “Class V Wildlife” in Tennessee means. Searching the Tennessee Wildlife Resource Agency home page gave me nothing. It was only until I backed up to Google that I found this definition:

Class V
This class includes such species that the commission, in conjunction with the commissioner of agriculture, may designate by rules and regulations as injurious to the environment. Species so designated may only be held in zoos under such conditions as to prevent the release or escape of such wildlife into the environment.

But I still can’t find a simple list of “Class V species” to figure out if Marmorkrebs are on it.

I will continue to investigate.

This is a nice example of that I made in a recent paper:

The regulations concerning crayfish trade are inconsistent across jurisdictions, hard to find, receive minimal enforcement, and are rarely enacted until after a problem occurs(.)