120 million year old bird-like dinosaur discovered with frog in its stomach

The impressively maintained skeleton of the dinosaur was found in Inner Mongolia.
Loukia Papadopoulos
A frog was found in the dinosaur's stomach.jpg
A frog was found in the dinosaur's stomach.

Heru Agung/iStock 

Over 120 million years ago, in what is now modern-day China, a bird-like dinosaur ate a small frog. Then something happened that ended its life and allowed it to be fossilized.

Scientists have uncovered the partial skeleton of a small flying dinosaur with an ancient frog in the remains of its gut, according to a report by Sci News published this Monday.

The dinosaur named Daurlong wangi was found to be a type of mid-sized dromaeosaurid – a group of bird-like predatory dinosaurs that primarily fed on fish, mammals, and other dinosaurs.

120 million year old bird-like dinosaur discovered with frog in its stomach
The Daurlong Wangi dinosaur

“Dromaeosauridae is a clade of small- to mid-sized theropod dinosaurs known from the Cretaceous of both hemispheres,” said Xuri Wang from the Institute of Geology at the Chinese Academy of Geological Sciences.

A rich diversity of dinosaurs

“The Early Cretaceous Jehol Biota from north-eastern China has provided a rich diversity of dromaeosaurids, the majority of which referred to Microraptorinae,” Dr. Wang added.

The impressively maintained skeleton was almost complete and was found at the Pigeon Hill locality of the Longjiang Formation in Inner Mongolia.

“The holotype of Daurlong wangi is an almost complete and articulated skeleton with a length of about 1.5 m,” the scientists said.

The fossil also featured the partial skeleton of an ancient frog in its gut contents, marking the first case of such intestinal preservation in a dinosaur closely related to birds. 

120 million year old bird-like dinosaur discovered with frog in its stomach
The fossil found in China.

“The reconstruction of the gastrointestinal track in extinct species, including dinosaurs, could be inferred, indirectly, from gut content remains; less frequently by the analysis of coprolite contents; and rarely from exceptionally preserved remnants of the soft tissues,” the scientists added.

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“The Daurlong wangi specimen shows the first case of intestinal preservation in a theropod lineage very close to bird ancestry.”

120 million year old bird-like dinosaur discovered with frog in its stomach
A fossil of a dinosaur with a frog in its gut.

Living in China

It is presumed that the bird-like dinosaur would have lived during the Early Cretaceous period, about 145 to 100 million years ago in Jehol Biota, a freshwater ecosystem in what is today northeastern China. 

The study was published in the journal Scientific Reports.

In June of 2019, researchers discovered the color blue in prehistoric feathers for the first time. Head researcher Frane Babarovic from the University of Bristol and his team showed how the blue feather melanosomes are distinct from the black, reddish brown and grey feather melanosomes. 

The team looked at plumage coloration schemes of modern representative fossil specimens and reconstructed which color was most likely to have appeared in the fossil specimen. By doing this, they could differentiate between grey and blue melanosomes. 

Then, in June of 2022, a team of researchers from Delhi University, India, discovered an abnormal bird-like 'egg-in-egg' dinosaur egg, a condition known as ovum-in-ovo or multi-shelled eggs, in the state of Madhya Pradesh's Dhar district, for the first time in fossil history.

Study abstract:

Dromaeosaurids were bird-like dinosaurs with a predatory ecology known to forage on fish, mammals and other dinosaurs. We describe Daurlong wangi gen. et sp. nov., a dromaeosaurid from the Lower Cretaceous Jehol Biota of Inner Mongolia, China. Exceptional preservation in this specimen includes a large bluish layer in the abdomen which represents one of the few occurrences of intestinal remnants among non-avian dinosaurs. Phylogenetically, Daurlong nests among a lineage of short-armed Jehol Biota species closer to eudromaeosaurs than microraptorines. The topographic correspondence between the exceptionally preserved intestine in the more stem-ward Scipionyx and the remnants in the more birdlike Daurlong provides a phylogenetic framework for inferring intestine tract extent in other theropods lacking fossilized visceral tissues. Gastrointestinal organization results conservative among faunivorous dinosaurs, with the evolution of a bird-like alimentary canal restricted to avialan theropods.