Scientists at Chicago's Field Museum and international collaborators have described a new species of Hero Shrew -- the mammal with the most bizarre lower spine（脊椎） on Earth. The interlocking vertebrae of the Hero Shrew render the spine four to five times more robust relative to body mass, a condition not found in any other mammal. The spine has been an enigma to evolutionary biologists, with no known adaptive significance. This new species of Hero Shrew, named Scutisorex thori, possesses features that may represent intermediate character states between the only other known Hero Shrew species (Scutisorex somereni), and other shrews（泼妇，悍妇）. In addition, a novel hypothesis for the function of the animal's expanded lower spine has been proposed. The study will be published July 24, 2013 edition of Biology Letters.

First discovered in 1910, the Hero Shrew's most notable feature was not revealed for another seven years, when a specimen was dissected to reveal the most peculiar backbone of any mammal. The remarkable spine of the Hero Shrew is unique among mammals, in that the lower vertebrae have multiple lateral processes that interlock with the processes of neighboring vertebra. The arrangement, along with surrounding musculature, affords the animal extraordinary strength, so much so that the Hero Shrew has traditionally been worn as a talisman.

"This shrew first came to light when explorers came to the eastern part of the Democratic Republic of Congo," said Bill Stanley, Director of Collections and zoologist at the Field Museum. "The explorers watched in amazement as a full-grown man stood on the back of the Hero Shrew, and the animal walked away, unharmed."

Until now, there have been no other species of this bizarre shrew. The new species described in this study represents a possible intermediate between the original Hero Shrew and other shrews, since is possesses an interlocking spine, but with fewer lower vertebrae and lateral processes than the first Hero Shrew species.

"You and I have five lumbar vertebrae," said Stanley. "And so do most other mammals, but the Hero Shrew at least 10. Scutisorex thori has eight vertebrae, and fewer lateral processes than the original species."