German scientists find survivor of ancient ant line

German biologists have discovered a new species of ant that they believe is a descendant of the oldest evolutionary lineage among living ants, dating back more than 100 million years.

Researchers from Karlsruhe's Natural History Museum found the three-mm long insect in the Amazon rainforest in 2003, and hope it will shed light on the early evolution of ants.

"It's by far the most spectacular find of my 26-year career," said museum biologist Manfred Verhaagh.

Scientists from Karlsruhe originally found two individuals of the same species in the Brazilian rainforest in 1998. However, due to an accident in the laboratory, the insect dried up, making further research impossible, Dr Verhaagh said.

In 2003 a student, from the museum's research body, Christian Rabeling, was in the forest investigating fungus-growing ants when he stumbled upon the tiny insect, now named Martialis heureka or "ant from Mars".

The species is like no other ant in its character combination, making it a representative of the oldest lineage in ant evolution still inhabiting the earth. Older lineages have only been seen in fossil form.

The lineage is believed to date back more than 100 million years, Dr Verhaagh said. The very first ants are believed to have evolved from wasp-like ancestors around 120 million years ago.

The last discovery of a new ant subfamily was in 1923, he added.