Description and Classification

Yongjinglong was a large, four-legged plant-eating dinosaur with a long neck and tail, typical of sauropods. While a complete skeleton has not yet been found, fossils include parts of the shoulder, forearm, ribs, and vertebrae. Based on these bones, paleontologists estimate that Yongjinglong could have reached lengths of around 50 to 60 feet (15 to 18 meters), making it a medium-sized member of the giant titanosaur group. One of its most remarkable features is its extremely long and relatively straight shoulder blade, or scapula.

Yongjinglong is classified as a titanosaur, which was a diverse group of sauropod dinosaurs that flourished during the Cretaceous period. Titanosaurs were the last surviving group of long-necked sauropods and included some of the largest land animals ever to have lived, such as Argentinosaurus and Patagotitan. Its discovery helps scientists understand how these giant dinosaurs evolved and spread across Asia. Yongjinglong appears to be a relatively specialized member within the titanosaur group, sharing characteristics with other titanosaurs from Asia and other continents.

Distinguishing Features

Yongjinglong had several unique anatomical features that help paleontologists identify it and distinguish it from other sauropods. These include:

• An exceptionally long and proportionally straight shoulder blade (scapula). This scapula is one of the longest known for any titanosaur relative to its overall body size.
• Robust and stout forearm bones (the ulna and radius).
• Specific characteristics in the structure of its vertebrae, particularly in the way different parts of the bones are shaped and connected.

Paleoenvironment and Diet

Yongjinglong lived in what is now northwestern China during the Early Cretaceous. At that time, the environment was likely a mix of river systems, floodplains, and forests, with a climate warmer than today. This region, part of the Hekou Group geological formation, supported a variety of plant life, which would have been the food source for Yongjinglong. As a herbivore, Yongjinglong would have used its long neck to reach leaves and branches high up in trees, possibly feeding on conifers, cycads, and ferns. It shared its environment with other dinosaurs, including other sauropods like Daxiatitan and Huanghetitan, and the ornithopod Jintasaurus.

Significance and Ongoing Research

The discovery of Yongjinglong is significant because it adds to our knowledge of titanosaurian sauropod diversity in Asia during the Early Cretaceous. Its unique features, especially the long scapula, provide important information about the anatomical variations and evolution within this group of dinosaurs. Studying Yongjinglong helps paleontologists piece together how titanosaurs spread across the globe and adapted to different environments.

Ongoing research on Yongjinglong involves further analysis of its known fossils to refine its position within the titanosaur family tree and to better understand its biology and how it moved. Paleontologists are also hopeful that more fossils of Yongjinglong and other dinosaurs will be discovered in the Hekou Group, potentially revealing more complete skeletons and providing a clearer picture of the ecosystems of Early Cretaceous China.