Got My Valentine Right Here

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A pair of aardvarks (Orycteropus afar) dozing together under an observational red light at the Philadelphia Zoo.  Aardvarks are sexually monomorphic, making them particularly difficult to sex (Parys 2012); however, the pair seen here are Sunshine (female) and AJ (male)*.  Image credit: Philadelphia Zoo / Curious Sengi.

To be honest, there is not much known about the love-life of aardvarks.

These animals are solitary for most of the year, until the rainy season floods out their haunts in the grasslands and forces them to retreat to higher ground.  This concentration of the population into a smaller area might initiate some aardvark love, as observers have noted male-female pairs “gambolling” and entering burrows together during this time.  However it may work, baby aardvarks appear about seven months later.

Aardvarks dig out sleeping holes with their powerful claws.  These chambers are usually just a little larger than the size of the body and the animals sleep curled up, snout covered by tail and hindfeet (Kingdon 1971).  Squeezing in two aardvarks into a single sleeping hole is a bit tight, but their predilection for snoozing snoot to foot is pretty darn cute!

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Image credit: Sebastien Millon via DeviantArt.

* A sad note:  AJ the aardvark recently died at the Philadelphia Zoo in January 2017.  Read about it here.

References

Kingdon, Jonathan.  1971.  East African Mammals:  An Atlas of Evolution in Africa, Volume I.  London:  Academic Press.

Parys, Astrid et al.  2012.  “Newcomers enrich the European zoo aardvark population.”  Afrotherian Conservation 9:  2 – 5.

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Getting Inside “The Elephant’s Head”

Greetings, fellow snurflers!

Pre-quals are coming up this week and as I am preparing a presentation on my proposed doctoral research into the evolutionary origins and specialization of mammalian facial muscles, I wanted to share with you a key text in this field of research.  Boas and Paulli’s two volume work, The Elephant’s Head, is not just scientifically significant, it is also a deeply beautiful illustrated work.

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The first volume of The Elephant’s Head was published in 1908, with the second volume following many years later in 1925.  As far as I can tell, this monograph cannot be obtained for love or money. . . . luckily, the Beinecke Rare Book and Manuscript Library at Yale had a copy available for study under the watchful eye of librarians.  The volumes consist of unbound, loose leaves.  The pages are huge, though ironically, not elephant folio-sized.  All of the images in this post are photographs I took while wobbling around on tiptoe, trying to get the whole page into frame without causing too much of a scene!  Image credit: Beinecke Rare Book & Manuscript Library / Curious Sengi.

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Schematic drawing showing muscle fiber orientation for the buccinator (cheek) and muscles surrounding the eyes.  Image credit: Beinecke Rare Book & Manuscript Library / Curious Sengi.

The supposed genesis of this masterwork was around the year 1899, with the death of a young Indian elephant from the Copenhagen Zoo.  Two Danish anatomists, Johan Erik Vesti Boas (1855 – 1935) and Simon Paulli (1865 – 1933), seized the opportunity to study the body, especially the head and proboscis.  What Boas and Paulli quickly discovered was that in order to properly understand the anatomy of the elephant’s highly specialized head, it was necessary to engage in a comparative survey of the facial musculature of a wide variety of mammals.  Over the next several years and what I imagine are many dozens of dissections later on specimens provided by the zoo, Boas and Paulli were prepared to publish the first installment of the most comprehensive zoological study of facial musculature ever before or since.

So here’s hoping that pre-quals goes by with the average amount of snot and tears (I am not even asking for the minimum amount), and that we can continue in this tradition of producing beautiful and meticulous comparative anatomy!

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Comparative snoot muscle anatomy. From top to bottom: elk, coati, hedgehog, dromedary, and wapiti. (I admit to being a bit confused about the nomenclature here, as my understanding is that the elk and wapiti generally refer to the same animal — any ideas?)  Image credit: Beinecke Rare Book & Manuscript Library / Curious Sengi.

Figures: Smiling Sengi

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The Naturalist’s Pocket Magazine, Vol. IV.  1800.  Image credit: Biodiversity Heritage Library via Flickr.

Oh gawd — do I really look like that when I smile?!?

About this image

For whatever reason, elephant shrews — or sengis — have long suffered from poor static representation.  This figure comes from a rather charming compendium called The Naturalist’s Pocket Magazine that was published in 7 volumes from 1798 to 1802.  The illustration itself was an embellished copy from an earlier work, Thomas Pennant’s (1726 – 1798) History of Quadrupeds, which featured two sengis.

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Figure of the “Elephant Shrew” from Pennant’s 3rd edition of History of Quadrupeds (1793).  Pennant’s description of the animal is sparse, noting that the animal is “with a very long, slender and little nose:  the whole animal of a deep brown color.”  The editors of The Naturalist’s Pocket Magazine opted not reproduce the top image, which looks rather like a juvenile individual.  Super cute!  Image credit:  Biodiversity Heritage Library.

The Naturalist’s Pocket Magazine says of the sengi:

Of this curious Shrew Mouse very little is known; and, till lately, it does not appear to have been noticed by naturalists. . . . One of the figures engraved by Pennant represents the animal with it’s snout turned upwards, the other is that which we have adopted. . . . If this Shrew has the faculty of dropping as well as elevating its snout, of which we have some doubt; it would, perhaps, have been best figured in that action, as most resembling the Elephant’s proboscis, from which it is named.

Though not as flexible as the elephant’s trunk, we now know that the sengi’s snoot is quite capable of wiggling!

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Where are your doubts now?  Image source: BBC Nature.  Gif from gifs.tastefullyoffensive.com via Giphy.

 

Image Source

The Naturalist’s Pocket Magazine; or, Compleat Cabinet of the Curiosities and Beauties of Nature.  Vol. IV.  1800.  Printed for Harrison, Cluse, and Co. by W. Justins, London.

Welcome to the Curious Sengi!

What is that thing?!?

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Macroscelides proboscideus, the short-eared elephant shrew.  Image credit:  “Elephant shrew : )” by Black Zack is licensed under CC BY 2.0.

 

The sengi is known by many names:

  • elephant shrew
  • jumping shrew
  • Rüsselspringer (German)
  • Elefantenspitzmaus (German)
  • Slurfhondjes (Dutch)
  • rat à trompe (French)
  • hanejinezumi (Japanese) 

This strange little creature defied description for generations of naturalists and scientists.  Despite all the attention common names give to its wonderful wiggly snoot, these animals are scientifically termed “Macroscelidea,” which means “large thigh.”  While this is certainly true for these active runners, it does seem rather rude to point this out when there are more charming, distinctive features available.

Over the years, the sengi has been variously classified alongside lagomorphs (rabbits and their kin), ungulates (hoofed mammals), scandentia (tree shrews), primates, and, of course, insectivores such as shrews and moles.  In 1998, a study based on molecular data revealed an astonishing relationship:  sengis share the family tree with tenrecs, aardvarks, golden moles, sirenians, hyrax, and. . . . elephants.

In a weirdly prophetic way, we found that elephant shrews are more closely related to elephants than they are to shrews!

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An unlikely family reunion.  Clockwise from top left:  African elephant (Loxodonta africana), golden-rumped sengi (Rhynchocyon chrysopygus), streaked tenrec (Hemicentetes nigriceps), dugong (Dugong dugon), Eastern tree hyrax (Dendrohyrax validus), and aardvark (Orycteropus afer).  Image credit:  Jonathan Kingdon via Hedges 2001.

This oddball assortment of mammals — now known as the superorder Afrotheria — is tied together by shared descent from a common ancestor in Africa dating back to at least the mid-Cretaceous period, approximately 100 million years ago.

While the molecular evidence supporting this relationship is robust, a coherent morphological narrative showing the evolution of this group of animals is still unknown.  What explains the presence of long, flexible noses in elephants and elephant shrews?  How is it possible for a related group of animals to generate both a tiny, blind, desert digger like the golden mole and over a thousand pounds of purely aquatic manatee?  The evidence for this amazing history is out there, in undiscovered fossils still encased in African rocks and in the bodies of the living animals themselves.  Nature is filled with such wonders and enigmas, if we only have the patience to uncover these stories.

This is an invitation to dig around and look closer. . .

 

References

Hedges, S.B.  2001.  “Afrotheria:  Plate Tectonics Meets Genomics.”  Proceedings of the National Academy of Sciences 98 (1):  1 – 2.  doi: 10.1073/pnas.98.1.1

Rathbun, G.S.  “Sengis.”  The Princeton Encyclopedia of Mammals.  Ed. D.W. Macdonald.  Princeton University Press.  76 – 81.

Stanhope, M.J. et al.  1998.  “Molecular Evidence for Multiple Origins of Insectivora and for a New Order of Endemic African Insectivore Mammals.”  Proceedings of the National Academy of Sciences 95 (17):  9967 – 9972.  doi: 10.1073/pnas.95.17.9967