Nimravs

I couldn’t help but look up Nimravidae; the name reminded me of ‘nimrods’, which of course have nothing to do with Nimravidae. Naturally, I didn’t know that until I looked it up.

The Nimravidae were a cat-like creature whose fossils have been found in North America and Eurasia. They are sometimes called ‘false saber-toothed cats’. They existed from about 40.4 million years ago to 7.2 million years ago, spanning some 33.2 million years.

It is thought that the ancestors of nimravids and cats diverged from a common ancestor about 50 million years ago. Nimravid diversity appears to have peaked about 28 million years ago before the family began a slow descent into extinction. This diversity was apparent in the size and shape of their teeth, as well as the size of the body. Some nimravidae were the size of modern lions, and they had various other smaller sizes down to the size of a small bobcat. Their legs and tails were proportionally shorter than those of true cats.

When nimravid first appeared, the global climate was warm and wet, but it trended cooler and drier shortly after that. This meant the lush forests were transforming to scrub and open woodland, where the nimravids flourished. North America and Asia were connected at the time, and they inhabited both. Europe was more of a cluster of islands rather than a continent at the time, but there must have been some land bridges, for the nimravids also found their way there.

Still later, the woodlands were replaced by savanna in North America and Asia, and the nimravids in those areas died out. Portions of humid forests continued in Europe for a time, but when those died out in the late Miocene, so did the rest of the nimravids.

One has to wonder if the saber-tooth tiger that Fred Flintstone put out of the house every evening was really a saber-tooth tiger or actually a nimravidae.

On second thought, there may be a tenuous connection between ‘nimrod’ and ‘nimravidae’. The dictionary tells me that ‘nimrod’ refers to a person who is good at hunting. As a carnivorous species, the nimravidae had to be good at hunting. Now I wonder if that influenced whoever named this family of creatures. Or what exactly does ‘nimravidae’ mean in whatever language they used to construct this name?

  

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

https://www.britannica.com/animal/Nimravidae

Dimetrodon

First, the dimetrodon was not a dinosaur. It went extinct some 40 million years before the first dinosaurs came into being, so it wasn’t even a contemporary of dinosaurs. However, it is often mistaken as a type of dinosaur, probably because life that long ago is all jumbled up in people’s minds.

Having said that, the dimetrodon lived around 295-272 million years ago. Its most prominent feature was a large neural spine sail on its back, formed by elongated spines extending from the vertebrae. Without the spine, it resembled a lizard, as it walked on 4 legs and had a tail. Its tall, curved skull had teeth of different sizes in the jaws. Most dimetrodon fossils have been found in southwestern United States, specifically from a deposit called the Red Beds of Texas and Oklahoma. However, there have been some fossils found in Germany. There are over a dozen species within the dimetrodon genus.

Although reptile-like in appearance, the dimetrodon is more closely related to mammals than to modern reptiles, although it is not a direct ancestor of mammals. It is assigned to the group ‘synapsids’, a group traditionally called ‘mammal-like reptiles’.

It was probably one of the apex predators of its time, feeding on fish, reptiles and amphibians. Smaller dimetrodon species may have had different roles in their ecological niche. The back sail may have been used to stabilize its spine or to heat and cool its body. Some recent studies argue that the sail would have been ineffective at removing heat, as large species have been discovered with small sails, and small species having large sails. This would appear to rule out heat regulation as its main purpose. It is proposed that the sail was most likely used in a courtship display, such as threatening rivals or showing off to potential mates.

Most species of dimetrodon range from 6 to 15 ft, and are estimated to have weighed between 60 to 550 lbs. The largest known species is about 13 ft. The smallest is 2 feet.

I remember seeing sail-backed giant lizards in a few movies. Always, they were supposed to be at least as tall as a man at their shoulder. Something that could easily eat a man without giving it much thought. This article only gave their length, not their height at their shoulder, so I can’t tell how much the movies may have ‘blown up’ their size. Considering they were most likely using a modern lizard with an fx sail glued to their back, the film crew probably got very close to make them look a threatening size.

How about you? Seen any good dimetrodon movies lately?

 

 

https://en.wikipedia.org/wiki/Dimetrodon#:~:text=Dimetrodon%20(%2Fda%C9%AA%CB%88m,member%20of%20the%20family%20Sphenacodontidae.

One Hump or Two?

A camel is an even-toed ungulate, which means it walks on 2 toes on each foot. They also have distinctive fatty deposits (humps) on the back. The Dromedary (94% of the world’s camel population) has 1 hump. The Bactrian camel (6% of the camel population) has 2 humps. The Wild Bactrian camel is a 3rd species and at less than 1% of the camel population, it is critically endangered. All of these camels are suited to a desert habitat. Except for the Wild Bactrian, camels have been domesticated for a long time, and have been a vital means of transport for passengers and cargo. As domesticated animals, they also provide food, such as milk and meat, and textiles via fiber and felt from hair.

 Sometimes the word camel is used in a wider sense, to include not only the Old World camels but also New World camelids (llama, alpaca, quanaco and the vicuna). These new world animals are technically camelids, not camels.

 Camels live an average of 40-50 years. An adult dromedary camel stands 6’1” at the shoulder and 7’1” at the hump, while Bactrian camels can be a foot taller. Camels can run in short bursts at 40 mph, and at a sustained speed of 25 mph. Dromedaries weight as much as 1,320 lbs, while Bactrians can get up to 2,200 lbs.

 The earliest known camel is called Protylopus and lived in North America 40 - 50 million years ago. It was about the size of a rabbit and lived in the open woodlands of what is now South Dakota. By 35 million years ago, it was the size of a goat and had many more traits similar to camels and llamas. Other ancient forms of camels or camelids were the Stenomylius and the long-necked Aepycamelus.

 The direct ancestor of modern camels (and perhaps of New World camelids as well) was Paracamelius, which existed 3 - 5 million years ago. It spread to South America via the Isthmus of Panama, and to the ‘Old World’ via the Bering Land Bridge. There have been surprising finds of fossil Paracamelius on Ellesmere Island (very much north of Canada and barely west of Greenland) which indicate the dromedary is descended from a larger, boreal browser whose hump may have evolved as an adaptation in a cold climate. This particular creature is estimated to have stood around 9 feet tall.

 Which just goes to show that given enough time, evolution can completely adapt to an environment that otherwise would kill the original animal.

  

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