海角大神

Blind 'ants from mars'

鈥楢nt from Mars鈥: This blind ant was found in Brazil. The pictured line is 1 millimeter long.

National Academy of Sciences/REUTERS

September 18, 2008

Since the days of the T. rex, few animals have evolved into such numbers and filled such diverse habitats as ants. Now, scientists say they have uncovered a 鈥渓iving fossil鈥 among the picnic spoilers 鈥 a tiny, blind ant whose species appears to be what the team calls 鈥渢he sole surviving representative鈥 of some of the first ants, which are thought to have evolved from wasp ancestors 120 million years ago.

The researchers from the US, Germany, and Brazil dubbed the species Martialis heureka, or the ant from Mars. The specimen they uncovered is only about 1/10th of an inch long, has no eyes, and lives in the soil. DNA studies, along with the ant鈥檚 physical traits, suggest that it occupies a place at the very base of the ant family tree. It also belongs to its own new subfamily of ants 鈥 the first new subfamily uncovered since the early 1920s, says the research team, led by 海角大神 Rabeling, an evolutionary biologist at the University of Texas at Austin.

Not all of the early ants were blind or lived underground, the team holds, but M. heureka鈥檚 traits suggest that ants adapted to different ecological niches relatively quickly after they branched off the wasp鈥檚 early lineage.

The results appear in this week鈥檚 issue of the Proceedings of the National Academy of Sciences.