Qianjiangsaurus changshengi

Qianjiangsaurus changshengi was a hadrosauroid ornithopod dinosaur from the Late Cretaceous of China, known from fossil remains recovered from the Zhengyang Formation in Qianjiang District, Chongqing Municipality, in the south-west of the country. Formally described in 2025 as a late-diverging non-hadrosaurid hadrosauroid, this taxon represents one of the most important forms for understanding the evolution and dispersal of “duck-billed dinosaurs” in East Asia during the Late Cretaceous. Its generic name refers to Qianjiang, the region where its fossils were discovered, while the specific epithet changshengi honours Changsheng, who was associated with the discovery and study of the material.

Geologically, Qianjiangsaurus changshengi comes from the upper part of the Zhengyang Formation, a continental unit of the Late Cretaceous preserving a faunal assemblage that includes non-hadrosaurid hadrosauroids, titanosaurs and tyrannosauroids. These deposits represent terrestrial environments of river plains, channels, flood zones and continental sedimentary systems in south-western China. Its discovery is particularly significant because it represents the first clearly distinctive dinosaur named from the Zhengyang Formation and the second formally named hadrosauroid from southern China, alongside Nanningosaurus dashiensis.

The holotype, catalogued as CLGRP V00016, consists of an incomplete and partially articulated skeleton. Known elements include parts of the lower skull, such as the predentary and left dentary, together with numerous postcranial elements that identify it as a non-hadrosaurid hadrosauroid. The original description highlighted several plesiomorphic features typical of basal or non-hadrosaurid hadrosauroids, including a broad U-shaped predentary in dorsal view, a dentary with no more than thirty tooth positions, and a coronoid process arranged at almost a right angle to the dorsal margin of the main body of the dentary.

From a morphometric perspective, Qianjiangsaurus changshengi was a medium- to large-sized ornithopod, although its exact body length must be regarded as approximate because of the incomplete nature of the skeleton. A cautious reconstruction would probably place it within the range of several metres in total length, comparable to other medium-sized non-hadrosaurid hadrosauroids, with a robust body, long tail, powerful hind limbs and the ability to move both bipedally and facultatively quadrupedally. Its overall anatomy would have been that of an active terrestrial herbivore, less specialised than more derived hadrosaurids but already clearly within the evolutionary lineage that led to the large duck-billed dinosaurs of the Late Cretaceous.

One of the most interesting aspects of Qianjiangsaurus changshengi comes from a second cranial specimen described later, which revealed the presence of a hollow supracranial crest in an early or non-lambeosaurine hadrosauroid. This discovery is particularly significant because hollow cranial crests are traditionally associated with lambeosaurines, in which they may have functioned in acoustic resonance, social communication and visual recognition. In Qianjiangsaurus, the presence of accessory endonasal cavities above the main nasal cavity suggests functional and anatomical convergence with more derived crested hadrosaurids, indicating that the evolution of complex cranial structures was more diverse than previously thought.

As a herbivore, Qianjiangsaurus changshengi would have used an anterior keratinous beak and relatively developed dental batteries to crop and process vegetation. Its diet probably included leaves, shoots, stems, ferns, young conifers, early angiosperms and other plant resources available in the fluvial environments of Late Cretaceous south-western China. Although it did not necessarily reach the same degree of dental specialisation as more derived hadrosaurids, its teeth and jaws show clear adaptations for efficient herbivorous feeding.

Qianjiangsaurus changshengi inhabited continental Asian ecosystems during a period of faunal exchange between different regions of East Asia. The original description interpreted its presence as supporting connections and interchange between dinosaur faunas during the Late Cretaceous, suggesting that non-hadrosaurid hadrosauroids were more widely distributed and diverse in southern China than previously recognised. In these landscapes, it would have lived alongside other large vertebrates, including titanosaurian sauropods and tyrannosauroid theropods, occupying the ecological role of a medium-sized herbivore within complex terrestrial communities.

Approximate Qianjiangsaurus Replica Dimensions

1:57 Scale — Complete Model
Length: 113 mm
Height: 47 mm
Width: 35 mm
Snout-to-tail length: 140 mm

1:35 Scale — Complete Model
Length: 184 mm
Height: 92 mm
Width: 57 mm
Snout-to-tail length: 229 mm