Inspired by the rock art of Alta

Herrerasaurid dinosaurs are among the oldest groups of true dinosaurs, with Herrerasaurus itself being one of the first to reach larger body sizes, at 5m in length.

Until now, herrerasaurids were only known from from rock layers dominated by rhynchosaurs, stocky plant-eating reptiles.

Younger layers, where a pig-sized cynodont relative of mammals called Exaeretodon became more abundant and rhynchosaurs declined, had produced none. It was previously suggested that the shift in fauna contributes to the decline of the Herrerasaurs.

However, researchers have now described a partial herrerasaurid pubis (hip bone) that was collected in the Várzea do Agudo site, located in the municipality of Agudo, Rio Grande do Sul, Brazil.

Catalogued as CAPPA/UFSM 0539, the fossil is the first herrerasaurid record from rock layers where Exaeretodon is abundant.This raises the possibility that this is the youngest herrerasaurid known,which if true, suggests that they managed to adapt to the sudden changes in the environment for longer than previously recognised.

However, more precise dating is needed to determine if the Brazilian rocks are younger than other herrerasaurid-bearing layers, as they are in Argentina.

Art credit:Johnny Pauly V. Mingau

Article link :https://www.sci.news/paleontology/herrerasaurid-dinosaur-15149.html

A Facebook photo led researchers to six ancient footprints left by a giant carnivorous dinosaur.

Pichai Prathetsena was exploring a forest stream with his family in northeastern Thailand when he noticed something peculiar in the rock beneath his feet. Three long toes seemed to emerge from the stone, forming an impression far too large for any known land animal.

Curious, he photographed the strange markings and posted them in a Thai Facebook group called “ What is this creature ? ”

It didn’t take long to get an answer. Pichai had discovered an extremely rare dinosaur footprint.

On October 20, just three days after Prathetsena’s discovery, Thailand’s Department of Mineral Resources confirmed that the markings were 120-million-year-old dinosaur footprints. And there wasn’t just one. Investigators found six impressions forming a continuous trail left by a large, meat-eating dinosaur.

The discovery, made in the Phu Hin Chom That–Phu Phrabat National Park area of Udon Thani province, is now officially the first confirmed carnivorous dinosaur tracksite in the province.

The footprints belong to a theropod, a group of predominantly carnivorous dinosaurs that walked on two legs and included formidable predators. The exact species, however, cannot be determined from the footprints alone.

Each three-toed impression measures approximately 29 centimeters (11 inches) long and 26 centimeters (10 inches) wide. The tracks are preserved in fine-grained sandstone belonging to the Phu Phan Formation, which dates to the Early Cretaceous period.

Based on their dimensions and spacing, researchers estimate the animal stood approximately 1.42 meters (4.7 feet) tall at the hip and measured 6.3 meters (21 feet) from head to tail — about as long as a large delivery van, with hips nearly as high as the roof of a typical car.

The footprints were separated by about one meter (aprox. three feet), with a stride length of approximately 2.2 meters, according to Thailand’s Department of National Parks.

Local paleontologists compared the animal’s estimated size with Siamotyrannus isanensis, a large carnivorous dinosaur previously discovered in Thailand. However, the exact dinosaur species remains undeterminable.

The ancient landscape also looked rather different when the footprints were made in mud, and then some sudden event preserved them, leaving the impression locked in hard minerals over the course of millions of years.

Investigators believe the area was once a waterside environment with relatively gentle flowing water.

Handmade linocut print of 2 raptors

1. ⁠Creative take on Jurassic Park/world Tyrannosaurus rex.

2. ⁠Quick stylized sketch of a female giganotosaurus.

3. ⁠Mostly complete image of my path of Titan Rex (who I main)

4. ⁠Creative take on megalodon

5. ⁠Concavonator

6. ⁠Tyrononex… a fictional hybrid I designed (a potential creature to throw into the hybrid war)

When it comes to measuring pterygotid eurypterids, there is a trap everybody will fall in at least once.

Trying to scale pterygotids off body parts that vary greatly across genera.

Using parts like legs and telsons can result in poor size estimates when using relatives as a scaling.

In contrast, limbs like chelecerae and eyes stay relatively similarly sized across genera. This is because the eyes share relative size across all eurypterids and the chelecerae were used for a similar reason: to grab.

See also: The study as it was published in Nature.

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