Natures wonders: fully armed plankton (Introduction)

by David Turell , Thursday, April 06, 2017, 02:35 (2787 days ago) @ David Turell

These guys are armed to the teeth:

http://www.livescience.com/58533-plankton-ballistic-weaponry-revealed.html?utm_source=l...

"Single-celled organisms of the sea shoot their prey with Spiderman webbing and tiny Gatling guns.

"Dinoflagellates called Nematodinium and Polykrikos are microscopic plankton, the kind of flotsam that whales gulp up by the ton. But these dinoflagellates, a type of protist, have their own drama-filled lives. They are hunters that eat other dinoflagellates, which themselves are bristling with armor, microscopic munitions and even chemical weapons.

"Dinoflagellates are "basically just objectively the coolest cells," Gavelis told Live Science. He previously discovered that Nematodinium has an eyespot with a lens and a light-sensitive pigment, suggesting that even though it's a single cell, it might, on some level, see.

"Nematodinium's weird clusters of weaponry are called nematocysts. Gavelis and his colleagues used scanning electron microscopy (SEM) to image these nematocysts as well as the nematocysts of another well-armed dinoflagellate, Polykrikos kofoidii.
They also captured the firing of P. kofoidii's weaponry in high-speed video for the first time.

"What they saw were some intricately complex structures: Nematodinium has nematocysts that are clustered in rosette shapes and look like the multibarrel configuration of a Gatling gun
 
"Now, new research finds that the tiny weapons of Nematodinium and related dinoflagellates are their own invention: Though the weapons look a lot like the stingers of jellyfish, the structures evolved independently, possibly because an arms race has developed in a plankton-eat-plankton world.

***

"Things got weird with P. kofoidii. This dinoflagellate, the researchers found, sports capsules on its surface, each of which is topped by a finger-like projection called a taeniocyst. When it comes into contact with prey, the taeniocyst explodes, perhaps shooting out an adhesive similar to Spider-Man's webbing, Gavelis said. The eruption of the taeniocyst, in turn, triggers the capsule, or nematocyst, to shoot out a coiled tube tipped with a pointy, dagger-like projection called a stylet. The stylet pierces its way out of the capsule and penetrates the prey. The coil dissolves, but the stylet is still attached to the predator dinoflagellate by a towline.

"'It uses that towline, basically like someone pulling a harpooned fish to its demise," Gavelis said.

***

"There were no relationships. The genes that build nematocysts in dinoflagellates are entirely different from those that build them in cnidarians, Gavelis said. The new findings, published March 31 in the journal Science Advances, mean that cnidarians and dinoflagellates evolved similar-looking weaponry separately."

Comment: A very simple animal has very complex weaponry. It is another example of convergence. I think this was not developed stepwise because of its complexity