The new species is the oldest Allosaurus described yet and was a top predator of its time

Like other members of the Allosaurus genus, A. jimmadseni boasted a suite of truly terrifying features. Study co-authors Mark Loewen, a paleontologist at the Natural History Museum of Utah, and Daniel Chure, a paleontologist at the Dinosaur National Monument in Utah, estimate that A. jimmadseni weighed up to 4,000 pounds and reached 26 to 29 feet in length at full size. This dino stomped around on two, three-toed feet and hunted prey with its long, curved claws and about 80 serrated teeth. (For perspective, the later-arriving T. rex maxed out closer to 40 feet in length and 20,000 pounds in weight.) This deadly combo probably equipped Allosaurus to take down their fair share of hefty creatures, including, perhaps, the spiky-tailed Stegosaurus.

Assigning specimens to the Allosaurus family tree has long been a point of contention in the field, according to a statement. While some have argued that as many as 12 separate species exist, the new study recognizes only two—A. jimmadseni and A. fragilis, which evolved some 5 million years later. Both were top predators in their respective ecosystems and represent some of the best-known dinosaurs in paleontology. But the older A. jimmadseni had a weaker skull that probably slightly weakened its ability to hunt, Loewen tells Courtney Linder at Popular Mechanics. So when A. fragilis showed up, he explains, it probably outcompeted its predecessor.

https://www.smithsonianmag.com/smart-news/meet-allosaurus-jimmadseni-newest-terrifying-jurassic-carnivore-180974056/

It’s a pity we can’t go back in time to the Jurassic era to have a look

Cymek said:

It’s a pity we can’t go back in time to the Jurassic era to have a look

Cymek said:

It’s a pity we can’t go back in time to the Jurassic era to have a look

I think there is an internet series about the past, titled, “Why you should not go back to the………”

PermeateFree said:

The new species is the oldest Allosaurus described yet and was a top predator of its time

Like other members of the Allosaurus genus, A. jimmadseni boasted a suite of truly terrifying features. Study co-authors Mark Loewen, a paleontologist at the Natural History Museum of Utah, and Daniel Chure, a paleontologist at the Dinosaur National Monument in Utah, estimate that A. jimmadseni weighed up to 4,000 pounds and reached 26 to 29 feet in length at full size. This dino stomped around on two, three-toed feet and hunted prey with its long, curved claws and about 80 serrated teeth. (For perspective, the later-arriving T. rex maxed out closer to 40 feet in length and 20,000 pounds in weight.) This deadly combo probably equipped Allosaurus to take down their fair share of hefty creatures, including, perhaps, the spiky-tailed Stegosaurus.

Assigning specimens to the Allosaurus family tree has long been a point of contention in the field, according to a statement. While some have argued that as many as 12 separate species exist, the new study recognizes only two—A. jimmadseni and A. fragilis, which evolved some 5 million years later. Both were top predators in their respective ecosystems and represent some of the best-known dinosaurs in paleontology. But the older A. jimmadseni had a weaker skull that probably slightly weakened its ability to hunt, Loewen tells Courtney Linder at Popular Mechanics. So when A. fragilis showed up, he explains, it probably outcompeted its predecessor.

https://www.smithsonianmag.com/smart-news/meet-allosaurus-jimmadseni-newest-terrifying-jurassic-carnivore-180974056/

Nice one

> While some have argued that as many as 12 separate species exist, the new study recognizes only two—A. jimmadseni and A. fragilis, which evolved some 5 million years later.

Oh dear oh dear oh dear.

I have noted such things before with dinosaur spacialists, but not among the allosaurs. Some people want to maximise the number of species and others want to minimise the number.

mollwollfumble said:

> While some have argued that as many as 12 separate species exist, the new study recognizes only two—A. jimmadseni and A. fragilis, which evolved some 5 million years later.

Oh dear oh dear oh dear.

I have noted such things before with dinosaur spacialists, but not among the allosaurs. Some people want to maximise the number of species and others want to minimise the number.

Lumpers and Spliters.

Checking up what wikipedia has to say about allosaurus.

> Allosaurus is a genus of carnivorous theropod dinosaur that lived 155 to 145 million years ago during the late Jurassic period (Kimmeridgian to late Tithonian). The bulk of Allosaurus remains have come from North America’s Morrison Formation, with material also known from Portugal. Allosaurus was the most common large theropod in the vast tract of Western American fossil-bearing rock known as the Morrison Formation, accounting for 70 to 75% of theropod specimens, and as such was at the top trophic level of the Morrison food web. The Morrison Formation is interpreted as a semiarid environment with distinct wet and dry seasons, and flat floodplains.

That’s a really narrow time span. mollwollfumble’s hypothesis of aquatic T rex could also apply to allosaurus. Highset eyes and brow ridge are also found among crocs. Short front legs allow manoeuvring underwater close the shore. Is the pelvis high enough to allow the hind legs to be moved forwards while the body is lying on the bottom of the pond?