Janský and Mutkovič, 2010

Janský V, Mutkovič A. 2010. Rak Procambarus sp. (Crustacea: Decapoda: Cambaridae) – prvý nález na slovensku. Acta Rerum Naturalium Musei Nationalis Slovaci 56: 64-67.

Abstract

Marbled crayfish – Procambarus sp. (Crustacea: Decapoda: Cambaridae) – first find in Slovakia. The species was found in gravelpit near-by the village Koplotovce, in May 2010. Distribution of this species in Europe and its risk for our nature is discused (sic).

Keywords: marbled crayfish • distribution • Slovakia

Note: Paper in Slovak.

Marmorkrebs found in Sweden, again

Apologies for being a bit behind the curve on this one, but I just saw the latest press release from back in July from the Swedish Agency for Marine and Water Management saying that Marmorkrebs had been found again this last summer, and in a different location that last autumn, and multiple individuals of different sizes.

This is not good news for Sweden, as it suggests Marmorkrebs are gaining a beachhead in that country.

 

Long overdue update, 30 June 2022: It wasn’t Marmorkrebs at all. It was still invasive, but a signal crayfish. It may have been a “mottled” colour pattern described here. The map is being updated.

External links

Nya fynd av misstänkt marmorkräfta har hittats i Västsverige

New Discoveries of Marbled Crayfish Cause Concern in Northern Europe (Note: English language press releases from this site do not appear to be archived as well as the Swedish language ones are.)

Picture from Swedish Agency for Marine and Water Management.

Quoth the crayfish, "Nevermore"

There are about eight native crayfish species in Russia, and those crayfish have made an impression on the vernacular. This expression means, "Never":

когда рак на горе свистнет (kogdá rak na goré svístnet) — “When the crawfish whistles on the mountain”.

For more ways of saying "Never," see here. It misses a favourite of mine, though. Apparently, in ancient Rome, an expression for "never" was, "When a mule foals."

External link

When Pigs Fly, Crayfish Whistle, and It Snows Red Snowflakes

Parthenogenesis primer

The Raptor Lab has a nice primer on parthenogenesis, although it focuses only on the phenomenon in pit vipers.

As if we required further proof life is weird, in walks parthenogenesis, an evolutionarily fascinating and frightening reproductive strategy, serving another round.

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.