Which one’s Pink?

Image: Arthur Anker
In 1975, on Have a Cigar, Pink Floyd wryly sang “The band is just fantastic / That is really what I think / Oh, by the way, which one’s Pink?”

Well, in the rather different world of snapping shrimps there really is no question which one’s pink; and, unlikely as it seems, these two worlds have now overlapped…

The strikingly bright pink-clawed species of pistol shrimp pictured above, and discovered on the Pacific coast of Panama, has been given the ultimate rock and roll name in recognition of the discoverers’ favourite rock band – Pink Floyd. In a paper published today, and co-authored by our head of research Sammy De Grave, it has been named as Synalpheus pinkfloydi.

Just like all good rock bands, pistol shrimps, or snapping shrimps, have an ability to generate substantial amounts of sonic energy. By closing its enlarged claw at rapid speed the shrimp creates a high-pressure cavitation bubble, the implosion of which results in one of the loudest sounds in the ocean – strong enough to stun or even kill a small fish.

Combined with its distinct, almost glowing-pink snapping claw, Synalpheus pinkfloydi is aptly named by the report’s authors: lead author Arthur Anker of the Universidade Federal de Goiás in Brazil, Kristin Hultgren of Seattle University in the USA, and Sammy De Grave here at the Museum.

If Synalpheus pinkfloydi had adorned the cover of Pink Floyd’s 1977 album Animals, rather than the famous dirigible pig. Image: Chris Jarvis
Sammy has been a lifelong Pink Floyd fan and has been waiting for the opportunity to name the right new species after the band.

I have been listening to Floyd since The Wall was released in 1979, when I was 14 years old. I’ve seen them play live several times since, including the Hyde Park reunion gig for Live8 in 2005. The description of this new species of pistol shrimp was the perfect opportunity to finally give a nod to my favourite band.

Synalpheus pinkfloydi is not the only pistol shrimp with such a lurid claw. Its closely-related and similar-looking sister species, Synalpheus antillensis, scientifically described in 1909, is found in the western Atlantic, including the Caribbean side of Panama. But the authors of the new paper found that the two species show considerable genetic divergence, granting S. pinkfloydi a new species status and its very own rock and roll name.

Arthur Anker, the report’s lead author, says:

I often play Pink Floyd as background music while I’m working, but now the band and my work have been happily combined in the scientific literature.

Another Shrimp in the Wall featuring Synalpheus pinkfloydi, the Oxford University Museum of Natural History building, and other Pink Floyd references. Artwork by Kate Pocklington.
Animals feature frequently in the Floyd back-catalogue. Indeed, the 1977 album Animals includes tracks titled Dogs, Sheep, and a suite of music dedicated to pigs. Then there’s Several Species of Small Furry Animals Gathered Together in a Cave and Grooving with a Pict from 1969’s Ummagumma. In fact, other biologists have already named a damselfly after that album: Umma gumma, in the family Calopterygidae.

However, until today there have been no crustacean names known to honour the band.

The full paper, Synalpheus pinkfloydi sp. nov., a new pistol shrimp from the tropical eastern Pacific (Decapoda: Alpheidae), by Arthur Anker, Kristin M. Hultgren, and Sammy De Grave is published by Zootaxa.

Out of order

Amphionides small

Our head of research, Sammy De Grave, is the lead author of a paper published in Scientific Reports last week. In this paper he and his co-authors propose to remove an entire ‘order’ of crustaceans. But just what is an order, and why would we want to get rid of one?

Biologists organise all life into ranked groups. The most familiar, and at the bottom level, are genus and species. These are recognisable in the format Homo sapiens, where Homo is the genus and sapiens is the species.

One of the higher groupings is called an order. For crustaceans, there are around 70,000 known species grouped into approximately 50 different orders. One of these orders is the subject of the paper mentioned above – it’s called Amphionidacea – and the odd thing about it is that it was created in 1973 for just one species, an enigmatic open-sea creature called Amphionides reynaudii.

Presumed adult female of Amphionides reynaudii (after Williamson, 1973)
Presumed adult female of Amphionides reynaudii (after Williamson, 1973)

Although the species has been known since 1833, relatively few specimens have been collected and almost none since 1973. Some larval stages have but recognised, but only three adult males have ever been found and no intact adult females have been collected. The reference illustration above is a composite of 43 damaged specimens.

Lacking good research specimens, the status of this creature has long been debated. Luckily, in 2011 Jose Landeira, a biologist on Gran Canaria, collected six specimens. As usual they were extensively damaged (you can see this in the photograph at the top), but a specialist genetic lab at National Taiwan Ocean University was able to extract some small fragments of DNA.

Building on earlier work by a US group, the sequences were analysed and the results show that Amphionides is not a separate order after all, but merely a shrimp. You can see where it fits in the taxonomic scheme of things by clicking the chart below.

Out of Order Fig3
Phylogram of the Decapoda order of crustaceans, which includes crayfish, crabs, lobsters, prawns and shrimp. The position of Amphionides indicated in red (click to enlarge)

In keeping with its oddball status, however, many questions remain unanswered. Amphionides larvae have been recorded across all oceans from the tropics to subtropics, but almost no known shrimp species have such a distribution as adults. And although the genetic analysis reveals a strong affinity to a single family of shrimp (Pandalidae), it remains unclear which genus or even species it could be the larvae for.

So Amphionides may be removed from its order, but the mystery of the little shrimp lingers yet…