Datonglong

Lore & Background

In 2008, a team from the Shanxi Museum of Geological and Mineral Science and Technology discovered the jaw of a euornithopod in the Kangdailiang quarry in Shanxi. The fossil, designated SXMG V 00005, consists of a portion of the lower jaw with preserved teeth. It was found in a layer of the Huiquanpu Formation, believed to date from the Cenomanian-Campanian timeframe, roughly 95 to 80 million years ago.

In 2016, the species Datonglong tianzhenensis was named and described by Xu Shicha, You Hailu, Wang Jiawei, Wang Suozhu, Yi Jian, and Jia Lei. The generic name refers to the city of Datong and the Chinese word long (龍), meaning 'dragon'. The specific name refers to its origins in Tianzhen county. Datonglong was one of eighteen dinosaur taxa from 2016 to be described in open access or free-to-read journals.

The holotype dentarium has a length of 34 centimetres and contains at least twenty-seven tooth positions, possibly up to twenty-nine. The teeth are large, standing up to 5.5 centimetres for an unerupted tooth, and are arranged in groups of three or four in the tooth battery. The processus coronoides is vertically oriented.

Reader's Guide

Datonglong is significant as a hadrosauroid dinosaur from the Late Cretaceous of China, adding to the known diversity of Asian ornithopods. Its description in 2016 was based on unique dental structures: in the middle and back of the jaw, two functional teeth are present in each tooth position, the main ridge on the inner side of the tooth is situated more to the back, and the secondary ridge is well developed with no further vertical ridges. The top of the tooth crown is bent slightly backwards. These features justified its recognition as a new genus. The fossil was one of eighteen dinosaur taxa from 2015 described in open access or free-to-read journals, reflecting a trend toward broader accessibility in paleontological research. Although classified within Hadrosauroidea and closely related to Hadrosauridae, this placement was not based on an exact cladistic analysis, leaving some uncertainty about its precise phylogenetic position. Datonglong provides insight into the evolution of hadrosauroid dental morphology and the Cretaceous ecosystems of northern China.

From Quarry to Name: The Story Behind Datonglong

In 2008, researchers affiliated with the Shanxi Museum of Geological and Mineral Science and Technology made an unassuming find in the Kangdailiang quarry of Shanxi Province: a jaw fragment belonging to a euornithopod dinosaur. That single piece of bone would not be formally recognized as a new species for nearly another decade. In 2016, a team of paleontologists—Xu Shicha, You Hailu, Wang Jiawei, Wang Suozhu, Yi Jian, and Jia Lei—published the formal description and naming of the animal as Datonglong tianzhenensis. The genus name is a straightforward geographic tribute: "Datong" honors the city of Datong in Shanxi, while "long" is the Chinese word for dragon. The species epithet "tianzhenensis" points to Tianzhen County, the specific locality where the fossil originated. Notably, Datonglong joined a small cohort of eighteen dinosaur taxa that year which were made publicly available through open-access or free-to-read journals, a choice that broadened the reach of the discovery well beyond the traditional paywalled paleontology literature.

A Jaw Full of Distinctions: Dental Anatomy

The holotype specimen, catalogued as SXMG V 00005, preserves a segment of the lower jaw bearing several intact teeth, and it is precisely this dentition that justified erecting a brand-new genus. In the middle and posterior regions of the jaw, each tooth position holds two functional teeth simultaneously—an unusual arrangement among ornithopods. The inner-facing tooth carries its primary ridge shifted noticeably toward the rear, while a secondary ridge is prominently developed; beyond those two, no additional vertical ridges appear. The crown's upper surface curves gently backward. The preserved dentarium stretches 34 centimetres and accommodates at least twenty-seven tooth positions, with the authors suggesting the full jaw may have held as many as twenty-nine. The processus coronoides rises in a distinctly vertical orientation. Individual teeth are substantial, reaching up to 5.5 centimetres in height before they have fully erupted. Rather than standing alone, the teeth are arranged in tight batteries of three or four, forming the grinding surfaces this herbivore used to process plant material.

Time and Place: A Late Cretaceous Herbivore of China

Datonglong roamed what is now the Shanxi region of northern China during the Late Cretaceous, a period when ornithopod dinosaurs were diversifying across the continent. The fossil was recovered from a stratum of the Huiquanpu Formation, a geological unit that preserves a window into the landscape of that era. Pinning down a precise age for the deposit remains uncertain, but the authors place it somewhere within the broad Cenomanian-to-Campanian interval, spanning roughly 95 to 80 million years ago. That wide range reflects the difficulty of correlating the formation's layers with the global timescale, yet it firmly situates Datonglong in the latter half of the Cretaceous, a time when hadrosauroid dinosaurs were becoming increasingly prominent in Asian ecosystems. As a herbivore, Datonglong occupied a familiar ecological niche: browsing or grazing on the low-growing vegetation that would have carpeted the floodplains and coastal plains of Late Cretaceous China, its robust tooth batteries adapted to break down tough plant fibres.

Where It Fits: Taxonomy and Scientific Context

Within the broader tree of ornithopod dinosaurs, Datonglong is assigned to the superfamily Hadrosauroidea, placing it as a close relative of the duck-billed hadrosaurs without actually belonging to the Hadrosauridae family itself. This distinction matters: it suggests Datonglong represents a side branch that diverged before the full radiation of true hadrosaurs, offering a glimpse into the transitional forms that connected earlier euornithopods to the later, more derived duck-billed dinosaurs. The authors themselves note that this placement was not derived from a comprehensive cladistic analysis, meaning the exact phylogenetic position of the genus remains somewhat tentative and open to revision as more material is discovered. As the sole representative of its genus, Datonglong tianzhenensis stands as a single data point in an otherwise sparse record of Late Cretaceous euornithopods from central China. Its description, published alongside seventeen other dinosaur taxa in open-access or free-to-read journals, also reflects a growing trend in paleontology toward making new species available to a wider audience without subscription barriers.