Date:

Oldest dinosaur bonebed reveals embryo development

Semitransparent flesh reconstruction of embryonic dinosaur inside egg, with skeleton (artwork by D. Mazierski)

- Advertisement -

A 190-million-year-old dinosaur bonebed near the city of Lufeng, in Yunnan, China has revealed for the first time how dinosaur embryos grew and developed in their eggs.

The great age of the embryos is unusual because almost all known dinosaur embryos are from the Cretaceous Period. The Cretaceous ended some 125 million years after the bones at the Lufeng site were buried and fossilized.

Led by University of Toronto Mississauga paleontologist Robert Reisz, an international team of scientists from Canada, Taiwan, the People’s Republic of China, Australia and Germany excavated and analyzed over 200 bones from individuals at different stages of embryonic development.

“We are opening a new window into the lives of dinosaurs,” says Reisz. “This is the first time we’ve been able to track the growth of embryonic dinosaurs as they developed. Our findings will have a major impact on our understanding of the biology of these animals.”

The bones represent about 20 embryonic individuals of the long-necked sauropodomorph Lufengosaurus (pictured left), the most common dinosaur in the region during the Early Jurassic period. An adult Lufengosaurus was approximately eight metres long.

The disarticulated bones probably came from several nests containing dinosaurs at various embryonic stages, giving Reisz’s team the rare opportunity to study ongoing growth patterns. Dinosaur embryos are more commonly found in single nests or partial nests, which offer only a snapshot of one developmental stage.

- Advertisement -

To investigate the dinosaurs’ development, the team concentrated on the largest embryonic bone, the femur. This bone showed a consistently rapid growth rate, doubling in length from 12 to 24 mm as the dinosaurs grew inside their eggs. Reisz says this very fast growth may indicate that sauropodomorphs like Lufengosaurus had a short incubation period.

Reisz’s team found that the femurs were being reshaped even as they were in the egg. Examination of the bones’ anatomy and internal structure showed that as they contracted and pulled on the hard bone tissue, the dinosaurs’ muscles played an active role in changing the shape of the developing femur. “This suggests that dinosaurs, like modern birds, moved around inside their eggs,” says Reisz. “It represents the first evidence of such movement in a dinosaur.”

The Taiwanese members of the team also discovered organic material inside the embryonic bones. Using precisely targeted infrared spectroscopy, they conducted chemical analyses of the dinosaur bone and found evidence of what Reisz says may be collagen fibres. Collagen is a protein characteristically found in bone.

“The bones of ancient animals are transformed to rock during the fossilization process,” says Reisz. “To find remnants of proteins in the embryos is really remarkable, particularly since these specimens are over 100 million years older than other fossils containing similar organic material.”

Only about one square metre of the bonebed has been excavated to date, but this small area also yielded pieces of eggshell, the oldest known for any terrestrial vertebrate. Reisz says this is the first time that even fragments of such delicate dinosaur eggshells, less than 100 microns thick, have been found in good condition.

“A find such as the Lufeng bonebed is extraordinarily rare in the fossil record, and is valuable for both its great age and the opportunity it offers to study dinosaur embryology,” says Reisz. “It greatly enhances our knowledge of how these remarkable animals from the beginning of the Age of Dinosaurs grew.”

Contributing Source : University of Toronto

HeritageDaily : Palaeontology News : Paleontology Press Releases

- Advertisement -

Stay Updated: Follow us on iOS, Android, Google News, Facebook, Instagram, Twitter, Threads, TikTok, LinkedIn, and our newsletter

spot_img
Mark Milligan
Mark Milligan
Mark Milligan is multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 8,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.
spot_img
spot_img
spot_img

Mobile Application

spot_img

Related Articles

Traces of Gloucester’s Roman past revealed in new findings

Archaeologists from Cotswold Archaeology have uncovered significant Roman remains during investigations at the Centre Severn development site in Barnwood, a suburb of Gloucester, England.

Study tells of family’s terrifying final moments at Roman Pompeii

A new study published in the E-Journal of the Pompeii Excavations sheds light on the final moments of a family living in Pompeii during the catastrophic eruption of Mount Vesuvius.

Archaeologists discover burials from the Iron Age and Viking Era

Archaeologists from the State Historical Museums and Arkeologerna recently completed an investigation of a significant burial site in Linköping, Sweden.

Hidden fortune discovered in Czech countryside

A 7-kilogram treasure hoard has been discovered by hikers on Zvičina Hill, located in Třebihošť-Mostek, Czechia.

Pre-war Jewish district uncovered in Lublin

Archaeologists from the Lublin Voivodeship Conservator of Monuments have uncovered traces of Lublin’s pre-war Jewish district during construction works at Zamkowa and Podwale streets.

Ornately decorated sarcophagus unearthed in “City of Gladiators”

Excavations in Stratonikeia, located in the Yatağan district of Muğla in southwestern Türkiye, have unearthed a 2,000-year-old sarcophagus from the Roman Imperial Age.

The mystery of a 1940’s Ford Woody discovered on USS Yorktown shipwreck

During a recent expedition aboard NOAA Ship Okeanos Explorer for the Papahānaumokuākea ROV and Mapping project, NOAA Ocean Exploration and its partners discovered a 1940s Ford Woody on the wreck of the USS Yorktown.

Roman phallus found at frontier fortress

Excavations at Vindolanda near Hadrian’s Wall have unearthed a miniature phallus pendant.