Researchers in Canada have found, for the first time ever, a photosynthetic symbionts in a vertebrate. A unicellular green alga,was found living INSIDE the cells of developing Spotted salamander embryos while still in the eggs! How these algae get inside vertebrate cells has not been determined. However, previous research showed that eggs that did not contain algae in the surrounding jelly mass were slower to develop than those which had algae present.
There are ways in which vertebrate cells eliminate foreign material and this discovery could help scientists explore what regulates this process.

Read more at: http://www.nature.com/news/2010/100730/full/news.2010.384.html