Researchers have discovered a rare species of ladybug that can tuck its head, in southwest Montana.

Ross Winton, a former Montana State University student, found a "headless" ladybird beetle in a trap he set in a sand dune. He thought that it was a body part of an ant, but then noticed that it was a bug and it was not actually "headless." It tucked its head inside a tube in its thorax just like turtles pulling its head back into its shell.

The specimen was sent to scientists in Australia, who were studying this group of insects. It was identified that the specimen is a male ladybird beetle that belongs to the group of the smallest ladybugs with a pinhead-sized head.

Unlike the normal ladybugs, the newly found insect did not have spots and was tanned instead of sporting a red color. Researchers named the male species as Allenius iviei.

A female ladybug of the same type has earlier been discovered in the south of the Centennial Valley in Idaho. Since male specimens are used to describe a new beetle species, Winton got the credit for discovering the bug.  

The male and the female specimens are the only two individuals from which the tiny species is known, making them the rarest species in the United States, MSU entomologist Michael Ivie said in a statement.

"The species is very unusual not only because of its small size, unique habitat and rarity, but the fact that its head is pulled back into a tube in its thorax makes its biology quite a mystery," said Ivie, who was Winton's former adviser.

"It was so unique that it was placed, along with another new species known from Baja California, in a new genus. While discovery of a new species of beetle in the USA is not an everyday event, a completely new genus is quite rare," he said.

The findings of the study are published in the journal Systemic Entomology.