Rhynchosaurs

Imagine a reptilian pig with a hammerhead, no visible ears, and a parrot-like beak, and you'll have a pretty good mental picture of a rhynchosaur.

Rhynchosaurs were herbivores that in some fossil localities account for 40 to 60% of the specimens found, making them the most abundant plant eaters on land. They were reptiles with stocky bodies and a powerful beak.

Early forms were small, less than a meter long, and typically lizard-like in build. They had narrow, wedge-shaped skulls with a few small, blunt teeth for eating plants.

Later versions grew up to two meters in length. The skull in these later forms were short, broad and triangular, becoming much wider than long, giving them a somewhat hammer-head appearance, although the eyes were set close together, near the top of the beak. The broad skull accommodated powerful jaw muscles that enabled the rhynchosaurs to cut up tough plant material. The teeth were modified into broad tooth plates, and the lower jaw fit into a groove on the upper jaw, enabling the ‘cutting’ of plant fibers.

The hind feet were equipped with massive claws, presumably for digging up roots and tubers, although digging claws are usually found on the front feet. Like many animals of their time, they spread all across Pangea, and thus across the world.

And that seems to about all there is to say about the rhynchosaurs. They lived during the Triassic era (251 to 199 million years ago), dying out just before herbivore dinosaurs appeared.

I think I would have found rhynchosaurs terrifying, particularly the larger ones, even though they were basically reptilian cows or deer. Let’s face it, the larger ones were as long as a man is tall, and who’s to say they wouldn’t try munching on this new plant called human that invaded their space, even if it didn’t sit still like other plants?

What do you think? If you had a time machine, would you venture back to visit them up close and personal?

 

https://ucmp.berkeley.edu/taxa/verts/archosaurs/rhynchosauria.php

https://en.wikipedia.org/wiki/Rhynchosaur

Giraffe Evolution

I’ve known for some time that giraffes and okapi are related. But in looking up giraffe evolution, I’ve discovered that giraffes are also (distantly) related to pronghorns, deer, musk deer, cattle, goats, sheep, wildebeests, and antelope. What a wide-ranging family! However, the opaki are their closest relative, so close that a 7-million year old fossil had a neck that was a blending of a giraffe neck and an opaki neck.

Giraffe and opaki ancestors once roamed all of Eurasia, but in modern times, they are only found in Africa. Giraffes live in the savanna grasslands, while okapi live in the rain forest.

One possible early ancestor of giraffes is the Canthumeryx, which lived in Libya. No one is sure when it lived; guesses range from 25 million years ago to 14.3 million years ago. It was a medium-sized animal, slender and antelope-like.

About 15 million years ago, Giraffokeryx appeared in the Indian subcontinent. It may have resembled an okapi or a small giraffe. It showed some definite lengthening of the neck.

The Sivatherium ranged throughout Africa and to the Indian subcontinent about 1 million years ago, and may have gone extinct as recently at 8,000 years ago, as ancient rock paintings greatly resemble them. The picture of a reconstruction of one show a pair of horns that look rather like the horns of a Texas longhorn, but only about a foot long each. The neck wasn’t as long as a modern giraffe, and the spots are depicted as being not quite so regular. It stood 7.2 feet tall at the shoulder, with a total height of 9.8 ft and a body weight of up to half a ton. Its shoulders were very strong to support the neck muscles required to life the heavy skull.

There was another giraffe-type animal that ranged from India to Turkey called the Bramatherium, which was closely related to the Sivatherium.

The Shansitherium was a superficially moose- or antelope-like giraffe from the Shanxi province in China. They were closely related to the Samotherium, which was rather like a half-way point between a giraffe and an opaki, as far as size goes.

Giraffes have horns! They are actually called ossicones, being made of bone and covered in furry skin. Some of their ancestors had 2, like modern giraffes, and some had 4. Sometimes they stuck up, or stuck up and curved back, or maybe they stuck out vertically. The Sivatherium horns as I described looked like small longhorns, did not look to be covered in furry skin, but they also had a pair of ossicones above their eyes.

So, if I ever want to make up a giraffe-like alien creature, I now know there is plenty of leeway for using my imagination!

https://evolution-institute.org/how-giraffes-evolved-such-a-large-neck/

https://en.wikipedia.org/wiki/Giraffidae

Unique Argentina Dino

Sometime around 2012, an Argentina rancher found an old bone sticking up out of the dirt. Intrigued, he scratched around, trying to dig it up, then contacted paleontologists at the local museum to come see what he had.

He had found some big bones. And when the paleontologists dug around, they discovered the remains of 6 of the biggest titanosaurs ever discovered.

Titanosaurs lived about 100 million years ago, on all the continents, including Antarctica, which was not covered in snow and ice, and may or may not have been located at the south pole at the time. The ‘Titans’ were herbivores. The most complete skeleton was for a young adult some 122 feet long (its neck was 39 feet) and weighing 70 tons (about the same weight as 10 modern African elephants). One of the femurs uncovered was 8 feet long; long enough to be a living room sofa, if it were more comfortable to sit on. How big would it have gotten when it was fully grown? How did it get that big? And what kind of creature - if any - could consider one of these dinner?

As I stated, there were (at least) 6 individuals found at this dig site, which at the time these Titans died, would have been the flood plain of a river. ALL of them were young adults. But they didn’t die as one group; there were at least 3 separate events that took lives, which may have been a few years to centuries apart. A theory is that the youngsters got separated from their herd and died from stress and hunger.

https://www.nytimes.com/2016/01/19/science/titanosaur-argentina-american-museum-of-natural-history.html