iologists exploring the ocean floor for new sea creatures have stumbled upon one of the largest known single-celled creatures, a bland, grape-sized distant cousin of the amoeba that may solve a thorny evolutionary question that has puzzled researchers for decades.
Researchers have seen similar blobs on the ocean floor before, but what distinguishes the new one, called a Bahamian Gromia, is that it moves -- albeit very slowly -- by rolling itself along the ocean floor, leaving behind distinctive trails.
It is the first time that a single-cell organism has been shown to leave such animal-like tracks.
Those trails are virtually indistinguishable from fossilized tracks from the Earth's pre-Cambrian era more than 530 million years ago, tracks which suggested the existence of multicellular life in a period before such organisms were thought to exist.
http://www.latimes.com/news/science/la-sci-seagrape25-2008nov25,0,6762946.story