Proboscideans roamed the globe for millions of years. But they weren't all "elephants". Beyond the bones, proportions and body shape can tell a lot about what an animal is.
Part 2 of Truncated, East Coast Elephants
Elephants are certainly famous. They belong to a long line of animals that went from small, hippo-like creatures to the most massive land animals on the planet. Proboscideans are most well known by their special teeth. Batteries of molars designed to replace each other in a conveyor belt fashion are a staple of their Order, while the development of incisors as tusks contributes to their identification. While not all Proboscideans have the same style of teeth, all but the most basal (less derived and recent) only have two types. So do all Proboscideans look alike? Not quite! Down below, we'll be exploring some of the differences.
Three major species of Proboscideans lived on the East Coast. Mammoths, Mastodons and Gomphotheres. Each linneage had diverged separately from the other, and had taken over the globe. Of the three, Mammoths were the newest. Gomphotheres and Mastodons had developed at a similar time, with Gomphotheres diverging once more later on with the emergence of Mammoths. Though each type of Proboscidean lived around the same time, they were only distantly related at this point. Each Proboscidean was no more original than the other, and around 11,000 years ago the last of the three disappeared from the earth. Thus, we'll be going through the facts on The American Mastodon (Mammut americanum), The Woolly Mammoth (Mammuthus primigenius) and The Gomphothere (Cuvieronius hyodon).
The Mastodon representative of the East Coast forests is the American Mastodon. At 7 to 10 feet on average, the Mastodon is the medium sized elephant in height alone. Though technically, a mastodon is an Elephantimorph. As a distant cousin of the elephants we know today, Mastodons were stockier, wider, and heavier. Their long skulls and conical teeth betray their origin, revealing that they had a browsing diet, unlike the mostly grazing elephants. As Mastodons and Gomphotheres split off at relatively the same time, the two groups are very similar. Traditionally, most Gomphotheres retained four tusks, and were more generalized. The Mastodon, it seems, was more of an obligate browser.
The most famous of the elephants, Mammoths roamed the plains of the Americas, found all across the East and West Coast. Mammoths are directly related to the modern elephant, being as closely related to asian elephants as the two species of african elephants. From about 8 to 11 feet tall, the Woolly Mammoth was often taller than the Mastodons they shared the world with. A sloping back and longer front limbs are characteristic of Mammoths, of which compensate for the often massive, curved tusks. These elephants made use of flat, grinding molars to devour their diet of grass. Alongside their flat teeth, Mammoths developed a more flat, vertical skull and copious amounts of hair to keep warm under. The Woolly Mammoth in particular was found more north than most elephants, being well adapted for the chilly steppes and plains.
Gomphotheres fit in as an oddball. Mastodons at the end of the Pleistocene had specialized into browsing. Mammoths had specialized into grazing. So what did Gomphotheres do? Pretty much everything. Gomphotheres like Cuvieronius were found deep in the south of the Americas, from the Carolinas to Argentina. When what is now Panama opened up to the animals of North America, Gomphotheres that had developed, including Cuvieronius and Notiomastodon, decided to jump ship and take up major residence in South America. As generalists, these animals competed with Mastodons and Mammoths, ultimately losing to both in North America. Stereotypical of Gomphotheres was a smaller size, less specialized teeth with more blunt cusps and spiral or dramatically curved tusks. Earlier Gomphotheres had four tusks, with two on the lower jaw, though it seems North American Proboscideans lost them almost entirely.
Think you can tell the difference now? Next time you go to a museum, try to guess who's who! There are many more species of Proboscideans who haven't been covered under Truncated, and even more we don't know much about! Only 11,000 years ago were these animals walking across what could have been your backyard, and went extinct in a blink of an eye. So while not every skeleton is a Mammoth, a Mastodon, or a Gomphothere, they were all just as important, and relevant to the past. We're still discovering more about these massive animals, and that will never change!
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