Discovering Toothless Bipedal Crocodile Relatives from 212 Million Years Ago in New Mexico

Paleontologists have unveiled a groundbreaking discovery: a new bipedal shubosaur archosaur, Rubble Jascus Expetatus, found in New Mexico. This finding enriches our understanding of the diverse prehistoric creatures that inhabited North America over 200 million years ago during the Triassic period.



Rubble Jascus Expetatus traversed its prehistoric environment on two legs, equipped with tiny arms and a beak-like structure devoid of teeth. Image credit: Jorge Gonzalez / NHMLAC Dinosaur Institute.

Rubble Jascus Expetatus belongs to the newly classified Shubosauridae family, which consists of ancient crocodilian relatives resembling bipedal theropod dinosaurs.

“Shubosauridae represents a unique group of Triassic poposauriforms found in western North America and Argentina,” explained Dr. Alan Turner of Stony Brook University and his team.

“These agile, bipedal, toothless creatures demonstrate a remarkable convergence with the ornithomimid theropod dinosaurs that thrived in the Cretaceous period.”

Currently, three recognized species of shubosaurs include Shubosaurus inexpectatus from the Cooper Canyon Formation in Texas, Ephigia ochiferae from the Coelophysis Quarry at the Chinle Formation in northern New Mexico, and Syrossuchus longiservicus found in the Lower Ischigualasto Formation of western Argentina.

Rubble Jascus Expetatus effectively bridges the fossil timeline between Shubosaurus inexpectatus and Ephigia ochiferae.

This fossil, estimated at around 212 million years old, was excavated from the Hayden Quarry in the Chinle Formation fossil forest of northern New Mexico, USA, yielding significant partial skeletons and other fossilized remains.

Paleontologists note that Rubble Jascus Expetatus exhibits minimal differences compared to its relatives, reinforcing a trend of remarkable skeletal conservatism within the Shubosauridae family.

“The anatomical similarities between the skeletal remains of these species suggest that this morphological consistency has persisted within the Shubosauridae of western North America for at least 10 million years,” the researchers stated.

Rubble Jascus Expetatus aligns well with the hypothesis of morphological conservatism and fits within the known stratigraphic range of North American shubosaurs.”

This discovery further supports the hypothesis that shubosaurs were primarily endemic to western North America, suggesting a unique pattern distinguishing them from many other rare Triassic reptile groups.

“Our phylogenetic analysis positions this shubosaur within the same clade as two other North American shubosaurs, reinforcing the concept of an endemic group of small, bipedal, toothless forms in the southwestern United States,” the researchers concluded.

The findings are detailed in a paper published in the May 26th edition of the Journal of Vertebrate Paleontology.

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Alan H. Turner et al. New Shubosaurid (Archosaur, Poposauridae) unearthed from the Late Triassic (Norian) Hayden Quarry in New Mexico, USA Journal of Vertebrate Paleontology, Published online on May 26, 2026. doi: 10.1080/02724634.2026.2618182

Source: www.sci.news

The pioneering toothless beak of the Cretaceous enantiornithine bird

Paleontologists have described a new species of enantiornithine bird with a toothless beak from the Chinese Jehor bird family. This discovery delayed the earliest appearance of edentulism (lack of teeth) in enantiornithines by about 48 million years.

fossil skeleton of Impalavis Attenborough and bird restoration. Image credit: Ville Sinkkkonen / Wang other., doi: 10.1016/j.cretres.2024.105867.

Impalavis Attenborough They lived in what is now northeastern China about 120 million years ago (early Cretaceous period).

This bird was a member of a group called. enantiornis, or “the opposite bird.” It is named for the feature of its shoulder joint that is “opposite” to that found in modern birds.

Enantiornithines were once the most diverse group of birds, but became extinct 66 million years ago following a meteorite impact that wiped out most dinosaurs.

Paleontologists are still working to understand why enantiornithids went extinct and the birds that gave rise to modern birds survived.

“The enantiornithines are very strange. Most of them had teeth and still had clawed fingers,” said Dr. Alex Clark. student at the University of Chicago and the Field Museum.

“If you were to travel back in time to northeast China 120 million years ago and walk around, you might have seen something that looked like a robin or a cardinal. But it had an open mouth and a bunch of teeth. . When you lift your wings, you’ll notice that you have little fingers.”

“Scientists previously thought that the first record of this group without teeth was from the late Cretaceous period, about 72 million years ago.”

“This little man is Impalavis Attenborough, pushing it back about 48 to 50 million years. Therefore, the lack of teeth, or edentulism, developed much earlier in this group than we thought. “

fossilized skeleton Impalavis Attenborough It was discovered by an amateur fossil collector near the village of Toudaoyingzi in northeastern China and donated to the Tianyu Natural Museum in Shandong Province.

“I think what attracted me to this specimen was the forelimbs, not the lack of teeth,” said Dr. Jingmai O’Connor, associate curator of fossil reptiles at the Field Museum.

“It had a huge bicrest, and a bony protrusion on top of the upper arm bone that had muscles attached to it.”

“I had seen such emblems on birds from the Late Cretaceous period, but never in the Early Cretaceous period like this one. That’s when I first suspected that it might be a new species. It was.”

rare wing bones Impalavis Attenborough Muscle attachments that allowed this bird to flap its wings with extra force may have been possible.

“We’re looking at potentially very strong wingbeats,” Clark said.

“Some of the bone features are similar to those of modern birds such as puffins and murres, which can flap their wings at crazy speeds, or of birds such as quail and pheasants. Although they are small birds, they generate enough force to instantly fly almost vertically when threatened.”

On the other hand, a toothless beak Impalavis Attenborough Modern toothless birds have a wide variety of diets, so researchers aren’t necessarily sure what they ate.

Like its fellow enantiornithines, and unlike modern birds, it does not appear to have a digestive system called a gizzard or gastric mill to help grind up its food.

“Although most enantiornithines appear to have been quite arboreal, differences in forelimb structure suggest that Impalavis Attenborough Although it probably still lived in trees, it probably went down to the ground to feed, and it had a unique diet compared to other enantiornithines. This suggests that there is a possibility, and that it may also explain why they lost their teeth.” said Dr. said Connor.

In their study, the scientists also reexamined previously known bird fossils. Chiapiavisand suggests that it was also an early toothless enantiornithine.

“This discovery… Impalavis Attenborough “We show that the lack of teeth may not have been as unique in early Cretaceous enantiornithines as previously thought,” the researchers said.

The specific name is Impalavis Attenborough Attenborough’s strange bird, after the naturalist Sir David Attenborough.

Sir David Attenborough said: “It is a great honor to have your name attached to a fossil, especially one as spectacular and important as this one.”

“It seems the history of birds is more complicated than we thought.”

“All birds are dinosaurs, but not all dinosaurs fall into the special type of dinosaur known as birds. All squares are rectangles, but not all rectangles are squares. Is the same.”

“The newly explained Impalavis Attenborough Since it’s a bird, it’s also a dinosaur.”

a paper description Impalavis Attenborough Published in an online journal Cretaceous research.

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Wang Xiaoli other. 2024. The first edentulous enantiornithines from the Early Cretaceous Jehol ornithians (Birds: Ornithorax). Cretaceous research 159: 105867; doi: 10.1016/j.cretres.2024.105867

Source: www.sci.news

China finds new species of toothless pterosaur

Chinese and Brazilian paleontologists identify new species of Chaoyangpteri pterosaurs from two specimens, one of which is the most complete and well-preserved Chaoyangpteri pterosaur ever recorded. It was announced that.



rebuilding the life of Meilifeilong Youhao. Image credit: Maurilio Oliveira.

This new species of pterosaur lived in what is now China during the Early Cretaceous period, between 125 and 113 million years ago.

Flying reptiles belong to Chamopteraa family of medium-sized and high-crowned pterosaurs known primarily from Asia.

dubbing Meilifeilong Youhaothis species was part of the Jehor biota, a terrestrial and freshwater ecosystem preserved within multilayered rock formations in northeastern China.

“Pterosaurs are an important and enigmatic group of flying reptiles of the Mesozoic Era that were among the first vertebrates to evolve active flight, and have filled every aerial environmental niche for almost 160 million years.” said Dr. Xiaolin Wang of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences. Academy of Sciences and its colleagues.

“Despite being a completely extinct group, they acquired a wide variety of morphologies during the period from the Late Triassic to the end of the Cretaceous.”

“Despite being found on every continent, China stands out by providing several new specimens that reveal not only different species, but also entire new clades, such as the azhdarchoid Chrysoptera.”

“This Cretaceous group of medium-sized and high-crowned pterosaurs is particularly well known from the Jehol biota. Chaoyangopterus zangi and Shenjoupterus chaoyangensis (At the time of description, the posterior region of the skull of Chaoyanptidae was the only one preserved, revealing that these toothless pterosaurs formed a new clade).



holotype of Meilifeilong Youhao; arrow indicates preserved soft tissue.Image credit: Wang other., doi: 10.1038/s41598-023-48076-7.

Two fossilized bodies Meilifeilong Youhao It was discovered in the Jiufutang Formation in Wuludao City, Liaoning Province, China.

“This holotype is particularly well preserved and represents an individual with a wingspan of up to approximately 2.16 meters (7.1 feet),” the paleontologists said.

“It consists of essentially all bones except for most of the tail, making it the most complete and well-preserved Chaoyanputid skeleton ever discovered.”

“The specimen mentioned consists only of the premaxilla and maxilla and anterior part of the palate and represents a smaller individual.”

size Meilifeilong Youhao basically the same as Meilifeiron Sanyainus (with a wingspan of 2.18 meters, or 7.2 feet), which, along with other characteristics, suggests that they represent different species of the same genus.

“This new species provides some new information about these rather enigmatic flying reptiles. palatal area” said the researchers.

“Additionally, it shows a stapes preserved in place, a rare phenomenon among pterosaurs.”

team’s paper Published in the Journal on December 21, 2023 scientific report.

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X-One other. 2023. A new toothless pterosaur from the Early Cretaceous Jehol biota. With comments on Chaoyoptera. science officer 13, 22642; doi: 10.1038/s41598-023-48076-7

Source: www.sci.news