What I’d like the next Syfy movie to be

Yes, in the wake of the viral success of Sharknado, I cannot help but pitch the next Syfy movie...

Volcanic base by Kröyer on Flickr; used under a Creative Commons license.

“Five clawed” crayfish

Check this claw!

A fisherman collected this crayfish in Schoharie Creek, near Delanson, New York and took this quick picture before using this as bait. Here’s his reaction, recorded with his phone:


Being a neuro guy, I wondered if the extra segments have muscle and neurons, or whether they were just “blank” exoskeleton. The word I received was that the extra claw was not moving.

The picture and video made its way to a colleague, Frank Dirrigl, and eventually to me. I have never seen a deformity like on this crayfish before. Anyone ever seen anything like this before? Leave word in the comments!

Additional, 18 July 2013: This deformity is unusual, but not rare. You can get these sorts of outgrowths fairly easily following injury. In particular, Nakatani and colleagues (1998) show pictures that are very reminiscent of the one above. Thanks to Joe Staton, Marina Araújo, and Gerhard Scholtz for these references:

References

Araújo M, dos Santos TC. 2012. New record of malformation in the true crab Ucides cordatus (Linnaeus, 1763) (Crustacea, Decapoda, Ucididae), at Brazilian coast. Revista Nordestina de Zoologia, Recife 6(1): 15-19.

Mantellatto FLM, O'Brien JJ, Alvare F. 2000. The first record of external abnormalities on abdomens of Callinectes ornatus (Portunidae) from Ubatuba Bay, Brazil. Nauplius 8(1): 9-97.

Nakatani, I., Oshida, Y., Kitahara, T. 1998. Induction of extra claws on the chelipeds of a crayfish, Procambarus clarkii. The Biological Bulletin 195: 52-59.

Przibram, H. 1921. Die Bruchdreifachbildung im Tierreich. Wilhelm Roux Archiv für Entwicklungsmechanik der Organismen 48: 205-444.

Shelton, P.M.J., Truby, P.R., Shelton, R.G.J. 1981. Naturally occurring abnormalities (Bruchdreifachbildungen) in the chelae of three species of Crustacea (Decapoda) and a possible explanation. Journal of Embryology and Experimental Morphology 63: 285-304.

Pinheiro MAA , de Toledo TR. 2010. Malformation in the crab Ucides cordatus (Linnaeus, 1763)(Crustacea, Brachyura, Ocypodidae), in São Vicente (SP), Brazil. Revista CEPSUL - Biodiversidade e Conservação Marinha 1(1): 61-65.

Crossposted at NeuroDojo.

Celebrate diversity: Rare boys

Artemia have featured on this blog before, mostly as possible food for Marmorkrebs. But like Marmorkrebs, there are parthenogenetic Artemia that reproduce asexually.

Mostly.

Maccari and colleagues show that Artemia sometimes produce little baby boy Artemia. There’re at low numbers; about 1% of offspring. I am impressed by just how many Artemia they looked at to determine this:

415 666 diploid parthenogenetic Artemia specimens were sexed in this experiment(.)

But while rare overall, a few sites, mostly in the Middle East were “hotspots” of male offspring, strongly indicating that there are population differences in this ability to produce males. This, in turn suggests that there may be situations in which this ability has an evolutionary advantage. That advantage might be that these males are completely fertile, and can mate with the females of sexual species that live in the same habitats. Maccari and company discuss the possibility that there are some advantages to having gene flow between species through this mechanism.

Additional, 12 July 2013: Carl Zimmer covers this paper at The Loom.

Reference

Maccari M, Gómez A, Hontoria F, Amat F. 2013. Functional rare males in diploid parthenogenetic Artemia. Journal of Evolutionary Biology: in press. DOI: 10.1111/jeb.12191

External links

The mystery of the rare male sea monkey

Photo by you get the picture on Flickr; used under Creative Commons license.

Gallardo and Aldridge, 2013

Gallardo B, Aldridge DC. 2013. The ‘dirty dozen’: socio-economic factors amplify the invasion potential of 12 high-risk aquatic invasive species in Great Britain and Ireland. Journal of Applied Ecology 50(3): 757–766. http://dx.doi.org/10.1111/1365-2664.12079

Abstract

1. Aquatic invasive species are a growing concern to environmental managers because of their diverse impacts on aquatic biodiversity and high eradication costs, necessitating effective management policies. In this study, we evaluate the ability of environmental and socio-economic factors to predict the risk of invasion in Great Britain and Ireland of 12 potential aquatic invaders covering all major aquatic groups. Despite their potential to inform risk assessments, this is the first time socio-economic factors related to propagule pressure have been specifically integrated in distribution modelling.
2. Species distribution models (SDM, MaxEnt algorithm) were calibrated with a set of environmental factors (e.g. bioclimatic, geographical and geological) and integrated with socio-economic (e.g. human influence index, population density, closeness to ports) predictors.
3. The inclusion of socio-economic factors in SDM did not affect accuracy scores (AUC already >0·90), but their effects were more pronounced in spatial predictions, resulting in up to a sixfold amplification of the area predicted suitable for each species. Despite the inclusion of potential surrogates of water chemistry (e.g. geology) and propagule pressure (e.g. population density), temperature-related variables were most important predictors of aquatic species' distributions.
4. According to SDM, the environmental suitability for a suite of invaders belonging to different taxonomic groups and regions of origin is greatest in east and south-east England and decreases towards the north and west. Multiple invasions in this region are of special concern, as species are known to modify their habitat facilitating subsequent invasions, thereby potentially exacerbating their impacts.
5. Major management regions to be prioritized in monitoring programmes include the Humber, Thames and Anglian River Basin Districts. Species of special concern include a mysid (Hemimysis anomala), a gammarid (Dikerogammarus villosus), a plant (Ludwigia grandiflora) and two crayfishes (Procambarus clarkii and P. fallax).
6. Synthesis and Applications. The inclusion of socio-economic factors in species distribution models has the potential to improve predictions of areas under a highest risk of multiple invasions and to help disentangle the complex interplay between biological invasions and global environmental and socio-economic processes. Such understanding is pivotal to prioritize limited resources for the optimum prevention and control of biological invasions.

Keywords: Ameiurus melas • Corbicula fluminalis • Dikerogammarus villosus • Dreissena r. bugensis • Hemimysis anomala • Ludwigia grandiflora • MaxEnt • Neogobius melanostomus • Procambarus sp. • species distribution models

Notes: Marmorkrebs is referred to in this paper as “Procambarus fallax.” The references and context make it clear, however, that the asexual Marmorkrebs are being modelled in this paper, not the sexual form of the slough crayfish.

The Supplemental material (S1) describes the European range of “P. fallax” as Germany and Great Britain. To the best of my knowledge, Marmorkrebs have never been found in the wild in Great Britain.

The crayfish / crawfish / crawdad war

Business Insider features this heat map of what people call crayfish in the United States. It’s all very confusing.

First, the question asks what people call “miniature lobsters”. I’m not sure that’s helpful. Do you have any idea how many kinds of crustaceans are called “lobsters”? There are clawed lobsters, spiny lobsters, slipper lobsters, squat lobsters...

Second, I’m particularly puzzled by people use “crawdad.” Not that they do, but that there are two disconnected blobs of green. I would have expected more continuity.

Maybe Americans should follow the lead of the Australians and call them all “yabbies.”

Hat tip to P.Z. Myers.

External links

22 Maps That Show How Americans Speak English Totally Differently From Each Other
It’s “crawdads”!

Crayfiction

Sometimes, a druid’s just got to catch some crayfish.

In this short story by Kevin Hearne, “A Test of Mettle,” druid initiate Granuaile MacTiernan is tasked with controlling invasive crayfish:

With Sonora’s guidance, sensed through the turquoise sphere at the base of my throat, I can feel the flow of water there, feel the gentle slowness under the rock, the place where a large crawdad has made its home. A crawdad from the Midwest that doesn’t belong on this side of the continental divide, an invasive species that’s been killing off the native fish by eating their eggs. Elementary school kids dumped them in here at the end of their crustacean unit, and their teachers, who should have known better, let them ravage an ecosystem in the process.

This story, and some others, is available for free from Kevin’s website. Thanks, Kevin, for bringing crayfish to art!

External links

Kevin Hearne: Short Stories
Kevin Hearne on Twitter

The Ecdysiast feature

The newest issue of The Crustacean Society’s newsletter, The Ecdysiast, is now available for viewing here. There are several articles of interest for readers. One is coverage of the SICB crayfish symposium that occurred in January It includes a note of the untimely death of Francesca Gherardi.

Also of interest are articles by Fred Schram, the general editor for the Journal of Crustacean Biology. In particular, “To be open or not to be open: That is the question” (page 7) is a look at open access from the perspective of someone in the thick of trying to maintain a journal in the face of a changing market, which includes declining Society membership.

Is OA the wave of the future? – maybe. However, we might suggest that “efficient” application of the OA model will lead to the collapse of many journals, especially those produced by small scholarly societies.

(Plug: If you are interested in crustacean biology, you should join the Society!)