Like A Waterscorpion Out Of Water

Explanation: There I was, walking a pathway at a lodge in Olisiti, northern Tanzania, when I happened to spot this cryptic, 3-inch (8-cm) long mini-monster. Usually associated with wetlands and water bodies, this is a waterscorpion but one that has stumped several entomologist colleagues and contacts.

Waterscorpions are not true scorpions but are so-named for their predatory forelegs and their long tail that, when bent forward over the back, bears a superficial resemblance to the stinger of their namesake. Instead of packing venom, the tail actually serves as a breathing tubule when the insect is submerged.

Waterscorpions can inflict a painful bite when handled, adding to its "scorpion" appellation.

Notice how well this waterscorpion blends into the brown of the walkway.
Perhaps it landed here thinking that this was a moist, muddy surface,
which would signal wetland habitat. Wrong!

This specimen belongs to the family Nepidae, which has been noted as being exclusively aquatic, although my friend here was quite a ways from any open water body, perhaps on a dispersal search of habitat. They have well-developed wings but seldom fly, so spotting this specimen was quite a chance observation.

So who is this, specifically? We can be sure it does belong to family Nepidae, and probably subfamily Nepinae that typically has a broad, flat body over 2 inches (5 cm) in length. Apparently, however, there is little written and scant research conducted on this family (or subfamily) in Africa.

After consulting with entomologists, the closest identification that can be made is that this may belong to the genus Borborophilus, and might be compared with the species B. afzelii (Stal), which is known from South Africa and is also called Nepa afzelii Stal. But it might also belong to the large genus Laccotrephes of the Old World tropics.

Essentially, this specimen may be an undescribed species.

The flat, broad body form of this specimen means that it is
not a member of the genus Ranatra, common in northwest U.S.
and which has a far more slender body form.
Who this is for certain remains a mystery!

In an instant, I looked away to make an adjustment on my camera, and when I turned back, my friend had vanished. These may be the only photos available to document this curious creature in a strange location, far from its habitat ... like a waterscorpion out of water.

Acknowledgments:
     My special thanks to entomologists Rob Cannings, Curator of Entomology Emeritus
of the Royal B.C. Museum, Canada, and to Dennis Paulson, Entomologist, Washington State USA, for their help with identification.

EPOW - Ecology Picture of the Week