Thursday, July 27, 2017

World's largest bony fish discovered

Seriously. In the 21st century, an Australian postdoc and her associates found the biggest bony fish in the world, a new species  (the fourth known) of the great ocean sunfish.
The sunfish is one of the strangest fish in the sea. Imagine a half-deflated circular blimp the size of a car.  It looks like a fish the Almighty got halfway through designing and then lost interest and just stuck the tailfins on.  It spends countless hours lying on its side, basking at the surface, slurping up jellyfish (and, unfortunately, plastic bags - thanks, humans) or diving to find them in deeper waters.. Its cartilage-underlayed-skin is so thick and hard it's difficult to harpoon one, so Pacific fishing cultures have generally left the animal alone.  The third species, still referred to simply as Mola Species C, was only found in 2009, by the way.
DNA collections from sunfish stranded, caught, or tagged indicated there were most likely four species of the fish (the signature one being Mola mola), but only three had ever been described. Maryanne, Nyegaard confirmed this oddity while examining known DNA records for the PhD dissertation. Once she'd determined there was a missing sunfish, she set about roaming beaches and museums to confirm a specimen. She kept it up for three years.  Fishermen sent her photos and DNA of an odd-looking sunfish they had caught, and then four such fish stranded in New Zealand, and Nyegaard was ready to write her name in scientific history along with the enigmatic Mola tecta. (She found other specimens in museum collections, where scientists had logged them in without noticing their oddities.) Sunfish are known for surpassing a metric ton in weight, but M. tecta is at the top of the scale, and appears to have the largest average size of any species. The longest specimen identified was 2.42 meters (just short of eight feet).  It lacks a protruding snout and a bumpy region on the back that other sunfish species develop as adults.
So welcome to the biggest bony fish in the world, a monster harmless to humans but startling in size and appearance, and outweighed among fishes only by the largest of sharks. It's about time you showed up.

The earliest known species, Mola mola (NOAA).

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