The dinosaur with two fingers used its massive claws to devour leaves

Illustration of Duonychus Tsogtbaatari, a Cretaceous theropod dinosaur

Masato Hatri

A new species of dinosaur found on the Mongolian building site has the largest fully preserved claws ever discovered. The bipedal herbivores only had two fingers in each hand, so they may have been used to grab a branch and pull it towards their mouth.

The 90 million-year-old fossil containing parts of the pelvis, arms and hands, and parts of numerous vertebrae was discovered in 2012 near Kambogd in the Gobi Desert, but is now properly studied and given a scientific name. Duonychus tsogtbaatari. The genus name means “two claws” and the species name honors Mongolian paleontologists Kishigjav tsogtbaatar.

Duonychus It's a small relative of Tericinosaurusthe features of the movie Jurassic World Dominion. Yoshitug Kobayashi In Hokkaido, Japan, his colleague estimates that the dinosaurs were about 3 meters long and weighed about 270 kilograms.

“Discovery Duonychus tsogtbaatari It's a big deal because it's the first known tericinosaurus with only two fingers,” says Kobayashi.

Overall, five groups of theropods have evolved to have only two fingers. Tyrannosaurus.

DuonychusThe nails are nearly 30 centimeters. Unusually, the nail sheath is made of keratin, the same material as the nail – is preserved.

“Keratin usually doesn't become fossilized. It fades long before bones do it,” says Kobayashi. “Most of the time, when we find dinosaur claws, we just look at the nucleus of the bone. But in life, the actual claws are covered in thick keratin sheaths, which are longer and curved.”

Team Members Darla Zelenitsky At the University of Calgary, Canada, finding a two-fingered Tericinosaurus was very surprising.

Duonychus Tsogtbaatari nails

Kobayashi et al.

“This is the largest 3D dinosaur claw that is completely preserved. “This claw is not preserved as the outline of the rock surrounding the bone. This is quite typical for fossils where the true claw is preserved. This claw is actually three-dimensional and forms a sheath around the underlying phalanx, similar to what is found on dog and cat's paws.”

Researchers believe that the nails are adaptations for grabbing and pulling down vegetation. Less fingers can make each one stronger, more flexible, narrower, and more controlled grips possible, Kobayashi says.

“The curved claws and extreme flexion suggest that they can be more easily connected to leaf branches and clusters,” he says. “Three fingers may have just got in the way, but two provided a more accurate and efficient grasp.”

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Source: www.newscientist.com

Mixedectes Pungens: An Enigmatic Mammal of the Early Ale Holocene with a Knack for Climbing Trees with Its Claws

Small Mixedectid Mammals Called Mixedectes Pungens Analysis of a remarkably complete skeletal structure discovered in New Mexico shows that the skeletal characteristics that live in the leaves were primarily dieting on the leaves, weighing about 1.3 kg.

Mixedectes Pungens (foreground) lived in the same forest as early primates Torrejonia Wilsoni (background). Image credit: Andrey Atuchin.

Mixedectes Pungens He lived in western North America during the early Ale Holocene period, about 62 million years ago.

First described in 1883 by the drinker Coop of the famous American paleontologist Edward, the species was previously known for its fossilized teeth and jawbone fragments.

In the new study, Professor Eric Salgis of Yale University and his colleagues looked into the new skeleton Mixedectes Pungens – The most complete dental-related skeletal structure still recovered for mixed-cutide mammals from the Nasimiento Formation in the San Juan Basin, New Mexico, USA.

“This 62 million-year-old skeleton of quality and integrity provides novel insights into the mixetide, including a much clearer picture of evolutionary relationships,” Professor Sargis said.

“Our findings show that they are relatives of primates and corgos – flying lemurs native to Southeast Asia – make them a fairly close human relative.”

The researchers determined that the new specimen belongs to a mature adult weighing about 1.3 kg.

The anatomy of the animal's limbs and nails indicates that it is dendritic and can cling perpendicular to the trunks and branches of a tree.

Its molars have a coat of arms to break down abrasive materials, suggesting that they were omnivorous and mostly ate the leaves.

“This fossil skeleton provides new evidence on the way placental mammals have become ecologically diverse following the extinction of dinosaurs,” says Dr. Stephen Chester, a researcher at the City University of New York and Brooklyn University at the Yale Peabody Museum.

“Characteristics such as greater weight and increased dependence on leaves. Mixedectes Pungens To thrive on the same tree that is likely to be shared with other early primate relatives. ”

Mixedectes Pungens Ale In North America during the early Holocene, it was very large for tree-inhabiting mammals.

For example, the new skeleton is significantly larger than the partial skeleton of Torrejonia Wilsonia small arboric mammal from an extinct group of primates called plesiadapiforms, discovered along with it.

meanwhile Mixedectes Pungens Living on the leaves, Torrejonia WilsoniThe meals were mainly made up of fruits.

These distinctions between size and diet suggest that the Mixeodotids occupied a unique ecological niche in the early days of the past, distinguishing them from contemporaries who inhabit their trees.

Two phylogenetic analyses conducted to clarify the evolutionary relationships of species confirmed that the mixed disease is Euarcontan, a mammalian group consisting of Tressue, primates and corgos.

“One analysis supported them as being an archaic primate, while the other wasn't,” Professor Sargis said.

“However, in the latter analysis we confirmed that Mixodectids are Primatomorphans, a group within Euarchonta, made up of primates and corgos, but not Treeshrews.”

“This study does not completely resolve the discussion about where Mixodectids belong to evolutionary trees, but it is significantly narrower.”

Survey results Today I'll be appearing in the journal Scientific Report.

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SGB ​​Chester et al. 2025. New remarkably complete skeleton of Mixodectes Cretaceous – reveals the argonism of protozoan mammals during the Oxalocene after mass extinction of the secondary genes. Sci Rep 15, 8041; doi:10.1038/s41598-025-90203-z

Source: www.sci.news