A new species of mammal (a sengi)

June 29, 2014 • 12:07 pm

New species of mammals aren’t found very often, but reader Roo called my attention to one in the Torygraph’s “Pictures of the day” showing a new species of what’s called a “shrew”. But it isn’t really a shrew, it’s a sengi, and can you believe this (from the California Academy’s press release)? (My emphasis):

Sengis are restricted to Africa and, despite their small size, are more closely related to elephants, sea cows, and aardvarks than they are to true shrews. Found in a remote area of Namibia, on the inland edge of the Namib Desert at the base of the Etendeka Plateau, scientists believe this new species went undescribed for so long because of the challenges of doing scientific research in such an isolated area. Yet it is precisely this isolation, and the unique environmental conditions in the region, that have given rise to this and other endemic organisms.

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A new mammal has been discovered in the remote desert of western African. The elephant shrew (Macroscelides micus) has a long-nose and looks like a mouse but is more closely related genetically to elephants scientists from the California Academy of Sciences who helped identify the tiny creature said. Picture: REUTERS/California Academy of Sciences

From the Cal Academy’s webpage on sengis:

Few mammals have had a more colorful history of misunderstood ancestry than the elephant-shrews, or sengis. Most species were first described by Western scientists in the mid to late 19th century, when they were considered closely related to true shrews, hedgehogs, and moles in the order Insectivora. Since then, there has been an increasing realization that they are not closely related to any other group of living mammals, resulting in biologists mistakenly associating them with ungulates, primates, and rabbits. The recent use of molecular techniques to study evolutionary relationships, in addition to the more traditional morphological methods, has confirmed that elephant-shrews represent an ancient monophyletic African radiation. Most biologists currently include the elephant-shrews in a new supercohort, the Afrotheria, which encompasses several other distinctive African groups or clades. These include elephants, sea cows, and hyraxes (the Paenungulata); the aardvark and elephant-shrews, and the golden-moles and tenrecs

This species, in the genus  Macroscelides, is described in a new paper in the Journal of Mammalogy (reference below), whose first author is Jack Dumbacher. Jack is one of our U of C grad-student alumni who in his Ph.D. thesis described the world’s first aposematic (and toxic) bird, the hooded pitohui.

The sengi’s arid habitat (photo from the paper):

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The species was identified originally by morphological traits, but the journal also shows that it’s quite distinct by molecular analysis of two mitochondrial and two nuclear genes:

While collecting and examining sengi specimens from southwestern Africa, Drs. Jack Dumbacher and Galen Rathbun encountered an unusual specimen collected in the remote northwestern region of Namibia that differed in appearance from any of the museum specimens that they had examined previously. The specimen was significantly smaller, had rust-colored fur, a large, hairless gland on the underside of its tail, and lacked dark skin pigment. Preliminary genetic analysis also showed important differences between this specimen and close relatives.

Suspecting they may have encountered a new species, the team—including research colleagues in Namibia, Timothy Osborne (California Academy of Sciences), Michael Griffin (Republic of Namibia Ministry of Environment and Tourism), and Seth Eiseb (National Museum of Namibia), all co-authors on the paper—set out on nine expeditions between 2005-2011. In total, the team collected 16 specimens for comparative analyses.

Nine expeditions to find this thing! That’s a lot of dough; I hope it’s sufficiently interesting. There are 19 previously described species of sengis, and you can find a gallery of all of them here.

How many new species of mammal are discovered in the wild each year? Put your guess below, and no cheating!

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Dumbacher, J. et al. 2014. A new species of round-eared sengi (genus Macroscelides) from Namibia. J. Mammalogy 95(3):443–454,

33 thoughts on “A new species of mammal (a sengi)

    1. I think they’re Elliott traps or another brand of the same thing – folding aluminium box traps with spring-loaded door.

      There are nightjars in the picture too, but they look just like basalt cobbles.

    1. It’s pretty crazy, but if one looks at the fine details of these things, it becomes apparent that elephant shrews are way different than a mouse.

      Kinda runs like a horse.

      Pretty neat.

      (On the other hand, hyraxes are creepy to me for some reason. Maybe it’s their paws, or smirk on their face, or their tusks. Yes, they have tusks..)

  1. Lets see, world about 6000 years old, about 4300 mammalian species, so on average that’s a bit below 2/3 of a species per year. So my guess is a little bit higher than Diane and a wee bit lower than mole or Roan (and being right for the wrong reason doesn’t make the answer wrong – just lucky!)

  2. I’ve known of the existence of elephant shrews because their lens crystallin is an aldehyde dehydrogenase. As I recall, the catalytic cysteine is not there, so they’re enzymatically inactive, too, as is often the case. (Lens crystallins are typically NAD-dependent dehydrogenases that have been recruited to the lens to serve a structural and perhaps UV-protective role, altho I’m not sure what the current consensus is on this. The specific dehydrogenase varies from species to species.) Since I studied structure/function relationships in this superfamily, the elephant shrew crystallin business was always an interesting (to me, anyway) factoid.

    It would be interesting to know what the lens crystallins are in other Afrotheria.

    And as to my guess, I can’t imagine the number is constant, so my guess is about 3/yr, of late, in a sliding window of 5yrs.

    1. I have some questions regarding lens crystallins. These are ‘evidence of evolution’ -type questions.
      Different animals, including various groups of vertebrates and invertebrates, seem to have recruited different enzymes to be their crystallins. The impression is that which enzyme had been used is rather haphazard, ranging from lactate dehydrogenases (and a lot of other dehydrogenases) –> quinone reducates, etc. But are they similar in species belonging to, say, the same order or family? Are they most similar in closely related species?

      1. I think that’s largely a safe bet, but I was never really up on the crystallin literature since the aldehyde dehydrogenases were inactive by a straightforward route (catalytic cysteine mutated), which was sort of the end of the story for me. Piatagorsky, as you may know, was the big name in the crystallin field.

        I’m not sure if he’s still active, but I did find this review from 11yrs ago that, since it’s in [NB: jac] an Oxford journal is available to anyone in its entirety! It looks like Table 1 addresses your question. (And I just learned that ALDH is a crystallin in molluscs, too.)

  3. I would never have said ‘shrew’ but might have said ‘a little like a shrew’. I would never have imagined they have more in common with the elephant than with the mouse/shrew though. What’s with convergence – don’t the gods have enough of an imagination to create other patterns?

  4. “How many new species of mammal are discovered in the wild each year?”

    To the nearest whole number: 0.

  5. Weren’t sengis one of the subjects of a BBC mini-series of programmes using very close-up photography to give a [animal]-eye view of their environment. It was broadcast about 6 months ago? Here we go : “Hidden Kingdoms”, broadcast in January this year.

  6. The rate of discovery/description of new mammal species is much higher than one might imagine. Over the last couple of decades I think it’s been running at about 20 or so per year. Most of them are small rodents or bats, and many are “cryptic” species that have only been revealed as distinct by molecular biology, but the recent list does include animals as large as monkeys, deer, tapirs and even a whale or two. No sasquatch yet though!

  7. I’ll go with .33 mammal species/year, and guess that most of those wouldn’t be never-before-seen animals but the splitting of a former single species into two, after further study.

    I wonder what the largest newly-discovered animal species of the last 10 years is.

    That said, this little furry buddy is very cute.

  8. New mammal species? I’d guess a dozen or so a year. As suggested by Dave most of them small rodents and bats (and other small fry) that do not make the headlines.
    New species of big land dwelling mammals (‘big’ being bigger than -what else?- a cat) are obviously rarer: once every three to five years?
    The largest recently discovered mammal? Should be one of those toothed whales.
    Hyraxes, locally known as ‘dassies’ or ‘klipdassies'(literally ‘small badgers’ resp. ‘small rock badgers’), are very common here, and in many areas e.g. Cape Peninsula, unafraid of humans.
    The link to the lens crystallins provided by Hemp is really fascinating, Thanks.

    1. Glad you liked that, too. The whole story seems a great illustration of the evolutionary principle that, if it works, it will be retained.

  9. Sengis are amazing little things. They move like lightning, but have to keep their runways clear of debris in order to do so, or else they trip and risk injury or getting caught. And boy, how they move!

    On a related note (pun intended), the Afrotheria are a pretty disparate bunch: they include elephants, dugongs, manatees, hyraxes, aardvarks, sengis, tenrecs, and golden moles. Pretty much all of them have been erroneously allied with other placentals at some point (for instance, elephants were lumped in with rhinos and hippos in “Pachyderma”, and golden moles were thought to be part of “Insectivora”).

  10. As Richard Dawkins recorded in at least one of his books, Sengis are one of The Small Five.

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