The finding provides strong evidence that human life started outside Earth, he stated.
The two-inch wide rock was one of several fragments of a meteorite that fell to earth in a spectacular fireball. They were still smoking when villagers living near the city of Polonnaruwa picked them up.
The fossils were discovered when the rocks were examined under a powerful scanning electron microscope in a British laboratory.They are similar to micro-organisms found in fossils from the dinosaur age 55 million years ago.
Though critics argued that the rock had probably become contaminated with algae fossils from Earth, Prof Wickramasinghe insisted that they are the remnants of extra-terrestrial life.
He noted that the algae organisms are similar to ones found in Earth fossils and that the rock also has other organisms they have not yet identified.