Scientific Illustration

biomedicalephemera:

Left: Armadillo Genus Alterum Clusii - “Armadillo, alternate genus”
Right: Armadillo siue Aiatochtli - “Armadillo or Gourd Rabbit [from Nahuatl language]”

All genus of armadillo have armored scutes that protect them from predators when they roll up, but the hardness and organization of those scutes varies. Because of this armor, the animals tend to be fairly slow. The denseness means that they’re also not naturally buoyant - however, the armadillo family has a counter for this! They inhale lots of air and expand their abdomen to twice the natural size, as well as being able to hold their breath for several minutes.

Ground armadillo has the dubious honor of being the only syphilis “cure” that you can contract Mycobacterium leprae from while preparing it. While I doubt Southerners are trying to cure syphilis with the armadillos they contact, it’s worth noting that over 70% of the leprosy cases in the Southern United States in the past two decades are thought to have armadillo-based origins.

A Description of the Nature of Four-Footed Beasts; With Their Figures Engraven in Brass. Joannes Jonstonus, 1655.

biomedicalephemera:

“Ai siue Ignavus” - Bradypus tridactylus

The title “Ai siue Ignavus” translates to “Ai, or Lazy”, which were the two common names for the Pale-throated sloth at the time. The Bradypus genus is the genus of three-toed sloths, which are the ones who are descended from a common ancestor of the giant ground sloths - two-toed sloths are actually not closely-related to either three-toed or giant sloths. 

Even though they’re not closely-related, both sloth families share a unique trait: they don’t have seven cervical vertebrae, which is a trait of almost all mammals, including those with very short necks (such as whales) and very long necks (such as giraffes). The two-toed sloths have only six cervical vertebrae, and the three-toed sloths have nine cervical vertebrae. The extra vertebrae in the three-toed sloths are what allow them to have such flexibility in their neck, and how they can turn their head 180 degrees.

A Description of the Nature of Four-Footed Beasts. Joannes Jonstonus, 1678.

biomedicalephemera:

Ornithorhynchus anatinus - Detail of Bill

The monotremes (egg-laying mammals) are the only mammalia with any sort of electroreception ability, and the platypus’ ability is far stronger than that of the echidna. They use neither sight nor smell while hunting for their food, which consists of small crustaceans and molluscs buried in lakes and slow-moving river bottoms. The platypus finds its food by sweeping its broad bill back and forth along the sediment, and the receptors that line the front and part of the sides of the bill pick up the electric field given off by its prey. It then uses its paws (with the flipper-ish part folded back) to dig out its snack.

Illustrations from the Proceedings of the Zoological Society of London, Vol. I: Mammalia. 1848-1860.

biomedicalephemera:

Pangolin - Manis spp.

The eight species of the pangolin genus, Manis, have been the object of curiosity for centuries, but it wasn’t until recently that their true position in the tree of life was understood. As insect-eating creatures that are highly specialized to lick ants and termites (and other nesting insects) from deep inside their nests, they were long thought to be closely related to the giant anteater and other Xenartha. It turns out, however, that this is an example of convergent evolution, where unrelated species develop the same specialization to perform the same function.

Thanks to genetic studies, we now know that the pangolins are most closely related to the order Carnivora. They’re the only extant member of their own order (Pholidota), however.

In addition to their highly-specialized tongues, pangolins have both scales and fur, providing a tough armor on their back and a soft under-belly, allowing them the ability to roll into a tight ball. Their skunk-like scent glands also allow them to spray an acrid deterrent in the face of predators prior to rolling up. Thanks to these defenses, the only serious predators that pangolins face are humans.

Unfortunately, two species of the genus are now known to be endangered thanks to traditional medicine and smuggling. Protection efforts and enforcement in most areas of rural Asia are lacking due to many factors, and habitat destruction combined with continued hunting does not lead to a positive outlook for those species affected.

The Book of the Animal Kingdom: Mammals. W. Percival Westell, 1910.

biomedicalephemera:

Talpa occidentalis - Spanish Mole

Fauna Iberica: Mamiferos. Angel Cabrera, 1914.

dailyfossil:

Onychonycteris

When: Eocene (all known fossils from a deposit 52.5 million years old)

Where: Wyoming, USA

What:  Onychonycteris is the most basal bat currently known. It differs from living bats in having claws on all five fingers, whereas living bats have lost them. This form also has relatively shorter arms and fingers, as well as longer legs and tail than any other bat, fossil or extant. Onychonycteris was an extremely important find, as allowed us to answer a long standing question about bat evolution: Which came first, flight or echolocation? This taxon was capable of flight, and detailed examination of the cranium revealed that it could not echolocate.  Thus, bats took to the skies before they developed a system for seeing with their ears. 

This amazing fossil is from the Green River fossil lagerstatten in southwestern Wyoming, and is one of two known complete specimens. This example is not the holotype (the specimen which bears the name) as while it looks absolutely gorgeous, the second specimen was arranged on the rock slab in such a way more of the skull could be studied. Additionally, this specimen was actually in the hands of a private collector, and thus not fully available to science.  That is until the specimen was mailed, unannounced, to Dr. Nancy Simmons at the American Museum of Natural History, New York.  She was working on publishing this taxon at the time, and the private collector had been informed of this, so the family sent the specimen to allow her the best examination possible. That was one awesome package to open, believe me! 

biomedicalephemera:

Top: Dorsal view and pectoral limb of Manatus americanus (now Trichechus manatus)
Bottom: African Elephant (Loxodonta africana)

These two creatures, though vastly different, are actually some of the most closely related extant sea and land mammalia.

Though the transition from land to sea occurred around the same time, the Sirenians (dugongs and manatees) are only distantly related to the Pinnipedia (seals and sea lions) and Cetacea (whales). The only living ocean-dwelling mammalian herbivores, Sirenians split off from a common ancestor with elephants around the middle of the Eocene epoch. This pig-like creature was very distinct from the small deer-like creatures that led to both the Cetaceans and modern horses.

The manatee’s land-dwelling origins can be seen in their pectoral limbs - there are “fingernails” at the end of each flipper, much more similar to the fingernails on an elephant’s foot than the claw-like nails you can see on the Pinnipedia.

Manatee: Transactions of the Zoological Society of London, Vol. VIII 1874.

Elephant: Wildlife of the World: A Descriptive Survey of the Geographical Distribution of Animals. Richard Lydekker, 1911.

dailyfossil:

Deinotherium - Hoe tusker

When: Mid-Miocene to Early Pleistocene (~10 million to 3 million years ago)

Where: Asia, Africa, and Europe

What: Deinotherium is a proboscidiean. The only two living species in Proboscidiea are the African and Indian elephants, but there are dozens of fossil species in this order. Unlike some other groups that not only have a much greater number of fossil species than living but a much wider variety of morphologies to go along with that, most fossil elephants well… look like elephants!  That being large, graviportal, and trunked.

However, even though there is less extreme differences in morphology within proboscidieans, there are still a lot of variations on the basic elephant body plan.  One great source of variation is in the tusks. The tusks of Deinotherium are enlarged incisors of its lower jaw whereas in modern elephants the tusks are enlarged upper incisors.  The clade containing Deinotheirum spilt off from the rest of the order roughly 40 million years ago, and the last common ancestor had slightly enlarged upper and lower incisors - thus it appears that some elephant clades further enlarged one set over the other. Oh, one last note about Deinotheirum… it was over 3 times the size of the modern african elephant. It was the 3rd largest land mammal ever to lumber accross the Earth! 

n264_w1150 by BioDivLibrary on Flickr.

Golden tailed Tupaia

The wild beasts of the world. v.1.
London :T. C. & E. C. Jack,[1909?]
biodiversitylibrary.org/item/62924

biomedicalephemera:

Porpoise fetus.

L’histoire naturelle des estranges poissons marins. By Pierre Belon, 1551.

(via biomedicalephemera)