Working in remote deserts of northwestern Namibia, scientists have discovered a new species of round-eared sengi, or elephant shrew. It’s the smallest of all 19 known sengis, and they’ve named it the Etendeka round-eared sengi, Macroscelides micus.
Elephant shrews are funny little things. They’re about the size of a mouse, yet they’re more closely related to elephants, sea cows, and aadrvarks than to true shrews and other rodents. They use their tiny, truck-like snouts to hunt insects.
After nine collecting trips between 2005 and 2011 -- and 5,616 trap-nights of effort -- an international team led by John Dumbacher of the California Academy of Sciences was rewarded with a total of 16 specimens of an “unusual” sengi. Compared with known elephant shrews (order Macroscelidea), they’re smaller and their fur and hair color are different.
These specimens weighed between 18 and 42 grams (with the heaviest one being a pregnant female), and they are about 190 millimeters long, including the tail. They’re fur is rusty colored and, without dark skin pigments, they have lighter, pinkish feet and ears. These new sengis also have a large hairless gland on the underside of the tail that they probably used for signaling others in the population.
For comparison, here’s a photo of the new Macroscelides micus (top) and the closely related Namib round-eared sengi (M. ﬂavicaudatus, bottom) from Dumbacher et al. 2014.
The new little guys seem to be confined to the gravel plains of the distinctively reddish-colored Etendeka geological formation in the Namib Desert. They appear to be reproductively isolated from other sengi species, and no evidence of hybridization was found. A preliminary genetic analysis showed divergence with their closet relatives at multiple DNA loci.
“Genetically, Macroscelides micus is very different from other members of the genus and it’s exciting to think that there are still areas of the world where even the mammal fauna is unknown and waiting to be explored,” Dumbacher says in a news release. The new species is named for “mickros,” which is Greek meaning small.
This is the third new elephant shrew species discovered in the wild in the last decade; all sengi species have been found in Africa. The description [pdf] is published in the Journal of Mammalogy this week.
Images: Galen Rathbun/California Academy of Sciences (top) & J.P. Dumbacher et al., Journal of Mammology 2014 (middle)