23 July 2013

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.

16 July 2013

“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:


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.

11 July 2013

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.


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.


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

External links

The mystery of the rare male sea monkey

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