Eye Lens and Refraction in Protozoa

Edward Babinski wrote,
"I once read about a protozoan species with a lens. A single-celled species with a lens inside that single cell. Weird."

Hans Thewissen wrote,
"Sharon, good to hear from you. I like diatoms and dinoflagellates. Certainly, diatoms are very important in geology, their shells are used to date rocks. Keep up the good work, it is neat to hear you talk about the eyespots and the evolution of the eye. I had not thought that far, being more vertebrate centered."

Glad to know you're still out there. Speaking of "vertebrate centered" -- I just got the information I was looking for (I think) -- big piece of the puzzle.

John Harshman wrote,
"I once read about a protozoan species with a lens. A single-celled species with a lens inside that single cell. Weird."

"He probably meant this:
~ tolweb.org/Dinoflagellates/2445

Go down to where it talks about ocelloids."

Complex Organelles
"Ocelloids: The ocelloid found in warnowiid genera is a complex organelle showing extraordinary resemblances to metazoan eyes, but at a subcellular level. It is entirely comparable to vertebrate eyes. Ocelloid types of different complexity and location in the cell are known (video clip of an ocelloid). Ocelloids consist of three primary components: a lens-like, refractile hyalosome, an ocular chamber, and a darkly pigmented melanosome (Greuet 1978). Microtubules are able to change the shape of the lens, and it appears that it can focus light on the surface of the retinoid (Francis 1967), although how this information is used is unclear."

Complete with photos / video.
Awesome. I'll certainly pass this on and make record of it.

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