Something Fishy

Well, it's been a fishy sort of day on twitter. First a tweet from @mocost (Mo Costandi) with news from the university of Washington about a fish called H psychedelica that bounces along the ocean floor using the current, odd jets of air from specially-located gills and even more impressively adapted leg-like flippers (there is a video of the fish 'walking' here) .

Then, this afternoon, a tweet from @BoingBoing with a link to a press release from Monteray Bay Aquarium Research Institute on an extraordinary fish with a transparent head.

Then, finally, a link to a short Nature paper from @NatureNews with the enticing headline: 'Fossils reveal early evidence for penetrative sex'. This too is about a fish, this time a fossil-fish which is having its anatomy re-assessed and finishes with an even better line from John Long of Monash University in Australia: '"We have an expression that humans like to get a leg over," Long says. "But these placoderms actually like to get a leg in."' There is a video here and it is really interesting.

Fossilised fish are often found in limestone nodules. Once a fossil is found the limestone around it can be dissolved away using the acid in vinegar: ethanoic acid. This old technique (discovered in the nineteen forties) has recently been developed using more dilute solutions to give a more delicate removal of the limestone. This has resulted in new detail being revealed including a mother fish with an umbilical cord and embryo attached.

It seems that this sort of 'live' reproduction must be initiated by penetrative sex, therefore when another class of fish was found to have an embryo (rather than as had been previously thought, a meal inside it) this meant that this class of fish relied on penetrative sex too. A re-examination of the fossils showed that some had the same sort of apparatus as modern day sharks - hence the expression by John Long, above.

So a very interesting day in terms of fish, but not, alas, in terms of silkworms. They are just eating...and growing.

Coincidentally, this is tonight's supper: cous cous, courgettes, mushrooms, red onions and peppers and a nice bit of...salmon (sans flipper-legs, see-through head...or anything else for that matter).