Sea spiders? Sounds like a B-movie horror story: ‘Sharkrantula”, maybe? Not at all. Sea spiders is the common name for pycnogonids (pik-noh-go-nids) which are a type of marine arthropod (joint-legged animal) which includes crustaceans like crabs, lobsters, shrimp and prawns, but also insects. But pycnos have actually got more in common with horseshoe crabs and spiders in terms of anatomy, so the name sea spiders is not too far from the truth.
The occur in seas all over the world from tropical reefs to frozen polar seas and from shallow water to depths of over 7,000 m. Most are tiny although some deep-sea species can grow to 90 cm. Pycnogonids have extremely reduced bodies in which the abdomen has almost disappeared, while the legs are long and clawed. Muscles are in some cases reduced to a single cell! They can even breathe and absorb food through their skin. As you can imagine their dietary needs are therefore very small. And yet they are predators that prey on corals and worms. The head has a long proboscis with an unusual mouth at the end and several simple eyes on a tube-like stalk. The head also has a pair of claws and a pair of attachments on which the eggs can be carried. All in all, it can be very hard to tell just which end of a pycnogonid is the head!
You might think so what? Spiders are creepy and yucky and iffy. But marine biologists love pycnos – they are just so strange and fascinating biologically.
But what has all this got to do with Chinese takeaways And taxonomical jokes?
Earlier this year I received the sad news that the head of the department I used to work in the Natural History Museum in London passed away. Roger Bamber (tribute by Dr. Tammy Horton) was a legend of a man and also an expert on pycnogonids – a pycnogonid taxonomist. Unlike the more familiar taxidermist (who stuffs and preserves dead animals), a taxonomist is an expert on the certain groups of animals or plants and decides what is and is not a new species – but come to think of it and they also work with dead animals and need to preserve them…sometimes they stuff them too…but its much more complex and tricky, I promise. There is a difference honestly!
Anyway, one of Hong Kong’s pycnos (there at least 6 species locally) was discovered by Roger. Tanystylum sinoabductus was identified in Hong Kong’s only marine reserve at Cape D’Aguilar where the Swire Institute of Marine Science is located. (Note: a marine reserve, unlike a marine park, does not allow any sort of anchorage or fishing, so its is completely protected – except for water pollution of course.) This particular pycno was found in exposed mussel beds. But at only roughly 1/2 a mm in size you will only see it with a magnifying glass and only recognize it under a microscope.
And now the for long awaited joke: the species is part of the genus Tanystylum, but the specific (species) name that Roger chose – sinoabductus -is the taxonomical joke. Sino in latin means chinese (duh!), and abductus – if you have not already guessed it – means ‘taken away’, thus sinoabductus is the “Chinese takeaway’. OMG, I hear you say. What an unfunny joke! You have to understand there is not much opportunity for humor in science (except in the pub after the work) and marine biologists spend a long time in the lab staring down a microscope or hours pouring data on a computer and reading and writing scientific papers any chance to get away with even a bit of humor is appreciated!
And just in case anybody in this era of social justice warriors and political correctness thinks that this species name could be racist: the other reason for the name is that the type species – that is the 1 animal that was selected as typical of the species and which represents the ‘gold standard’ for that species – now resides in the National Museum of Wales in Cardiff, UK. Thus this Chinese sea spider species was in fact ‘taken away’ to a noted museum for that group of animal (which is standard practice as well, so no accusations of kidnapping or robbery please!).