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A formidable predator that lived 340 million years ago has been dubbed “the T Rex of its day.”
Named Whatcheeria, it had huge razor sharp teeth and bone crushing jaws that snapped animals in half.
The tetrapod was one in all the primary creatures to hunt on land and topped the food chain of the time, say scientists.
It had a salamander like body and long narrow head, reaching greater than six feet from nose to tail.
Co-author Ben Otoo, a PhD student on the University of Chicago, said: “Should you saw Whatcheeria in life, it could probably seem like a giant crocodile-shaped salamander, with a narrow head and plenty of teeth.
“If it really curled up, probably to an uncomfortable extent, it could slot in your bathtub, but neither you nor it could want it to be there.”
It grew unusually big for its time by front loading its growth in its youth. The US team analysed 350 specimens housed in town’s Field Museum.
They vary from single bones to finish skeletons and were discovered in a limestone quarry near the town of What Cheer, Iowa.
Modern reptiles and amphibians that descend from the beast develop slowly and steadily.
Bony grooves in its skull for sensory organs reveal it spent most of its time underwater. Sturdy leg bones could have helped it hunker down in a single spot and wait for prey to swim by.
(Kate Golembiewski, Field Museum )
Mr Otoo said: “It probably would have spent a whole lot of time near the bottoms of rivers and lakes, lunging out and eating whatever it liked. You actually could call this thing ‘the T. rex of its time.’”
Whatcheeria is a component of the lineage that eventually evolved into the four-limbed animals alive today – including humans.
Co creator Dr Ken Angielczyk, a curator on the Field Museum, said: “Whatcheeria is more closely related to living tetrapods like amphibians and reptiles and mammals than it’s to the rest, nevertheless it falls outside of those modern groups.
“That signifies that it may possibly help us find out about how tetrapods, including us, evolved.”
Tetrapods include amphibians, reptiles, mammals and birds. They evolved from the lobe-finned fishes in the center Devonian Period, which began 419 million 12 months ago.
Dr Angielczyk said: “Most early tetrapods are known from only one skeleton, should you’re lucky – in a whole lot of cases just a fraction of a single bone.”
With so many individuals on the Field, the researchers have been capable of spot variation throughout the species.
Some Whatcheeria are six and a half feet long, while others are much smaller. Meaning there was a possibility to review how they grew.
(Kate Golembiewski, Field Museum )
Lead creator Professor Megan Whitney, of Loyola University, Chicago, said: “Examining these fossils is like reading a storybook, and we try to read as many chapters as possible by taking a look at how juveniles grow build up to maturity.
“Due to where Whatcheeria sits within the early tetrapod family tree, we wanted to focus on this animal and have a look at its storybook at different stages of life.”
The researchers analysed thigh bones from nine individuals starting from juvenile to adult under a microscope. When an animal is growing, it creates latest layers.
Mr Otoo said: You may see a seasonal pattern where the animal is growing rather a lot throughout the spring and summer after which stopping in winter and resuming the following spring.
“By examining how thick the expansion rings are over the course of an animal’s life, you’ll be able to determine if the animal’s growing constantly throughout its lifetime, perhaps with some temporary interruptions, or principally growing to an adult size, then stopping.”
In modern tetrapods, some animals grow rather a lot as juveniles after which stop once they reach maturity. Birds and mammals, including us, are like that.
But other animals like crocodiles and lots of amphibians continue to grow little by little their whole lives.
The study found Whatcheeria grew rapidly when it was young, after which leveled off over time.
Prof Whitney even found evidence of fibrolamellar bone, which is primary bone tissue related to fast growth. The invention helps illuminate Whatcheeria’s lifestyle.
Co creator Dr Stephanie Pierce, of Harvard University, Boston, said: “Should you are going to be a top predator, a really large animal, it may possibly be a competitive advantage to get big quickly because it makes it easier to hunt other animals, and harder for other predators to hunt you.
“It may well even be a useful survival strategy when living in unpredictable environments, comparable to the lake system Whatcheeria inhabited, which went through seasonal dying periods.”
But growing really big really fast takes an infinite amount of energy, which is usually a problem if there is just not enough food and resources.
It is less complicated to get simply enough food to get a little bit bit larger, the identical way it’s easier to make smaller monthly rental payments than it’s to avoid wasting up for a giant downpayment on a house.
In addition to shedding fresh light on the early tetrapods, the findings are a reminder that evolution isn’t a neat stepwise process, but a series of experiments.
Added Dr Angielczyk: “Evolution is about trying out different lifestyles and mixtures of features.
“And so that you get an animal like Whatcheeria that Is an early tetrapod, nevertheless it Can be a reasonably fast-growing one. It’s a very big one for its time.
“It has this weird skeleton that’s potentially letting it do some things that a few of its contemporaries weren’t. It’s an experiment in the right way to be a giant predator, and it shows how diverse life on Earth was and still is.”