Fossil of Ancient Long-Tailed Bird Found in China

A new genus and species of jeholornithiform avialan that lived during the Cretaceous period has been identified from a nearly-complete specimen found in China.

Named Kompsornis longicaudus, the prehistoric bird lived approximately 120 million years ago (Early Cretaceous epoch).

It belongs to Jeholornithiformes, a group of long-tailed birds slightly more advanced than the famous Archaeopteryx.

These creatures are characterized by possessing a peculiar combination of primitive and derived bird features, such as the long bony tail and powerful flight ability.

“Kompsornis longicaudus further enriches the diversification of Jeholornithiformes and provides more information for understanding the morphologies of this group and bone fusion in the evolution of avialan dinosaurs,” Dr. Xuri Wang from the Institute of Geology of the Chinese Academy of Geological Sciences and colleagues from China, Slovak Republic and Italy said in their paper.

Kompsornis longicaudus was part of the Jehol Biota, an Early Cretaceous terrestrial and freshwater ecosystem preserved in a multi-layered rock formation cropping out in the Chinese provinces of Liaoning, Hebei and Inner Mongolia.

The nearly-complete and articulated adult individual of the new bird was recovered from the Jiufotang Formation at the Lingyuan locality in Liaoning Province.

Kompsornis longicaudus is a large long-tailed avialan with the unique combination of features — it had extremely elongated tail, forelimb, and middle caudal vertebrae.

“Kompsornis longicaudus possessed completely fused sternum and pelvis, which is the first time to recognize a combination of advanced features among jeholornithiforms and non-pygostylian avialans,” the researchers said.

“The osteohistological investigation based on the rib of Kompsornis longicaudus indicates that it perished in the fifth year of life, approaching the somatic maturity but not reaching the fully-grown stage.”

“Comparing with other adult Jeholornis still with unfused sternum and pelvis, we assure that this feature is unrelated with ontogeny but suggests that more than one growth strategy evolved in Jeholornithiformes.”

According to the team, their discovery brings the total number of jeholornithiform species to six: Kompsornis longicaudus, Shenzhouraptor sinensis, Jixiangornis orientalis, Jeholornis prima, Jeholornis palmapenis, and Jeholornis curvipes.

“The new discovery further enriches the diversity of Jeholornithiformes and suggests an unexpected developmental disparity in ossification patterns along the lineage from non-avian dinosaurs to birds,” the scientists said.

The team’s paper was published in the Journal of Asian Earth Sciences.