The dorsal and caudal vertebrae of the Sihui Museum specimen Photos: Courtesy of a research team led by Xing Lida from China University of Geosciences (Beijing)
Chinese and Canadian academicians have jointly announced an unprecedented discovery of fossils belonging to the duck-billed dinosaur tribe Lambeosaurini (Hadrosauridae: Lambeosaurinae) in South China.
The Lambeosaurini fossils at the Sihui Museum, Guangdong Province represent the first discovery of a Laishosaurinae dinosaur in South China, and is the only evidence of the spread of North American dinosaurs to South China in the Late Cretaceous.
The Sihui Museum specimen is of great significance for the study of biological paleogeography. It provides valuable material for studying the ecological conditions of different regions before the mass extinction at the end of the Cretaceous, experts said.
The research paper was recently published on Historical Biology, an international journal of paleobiology.
Restoration drawing of the Sihui Museum specimen by Han Zhixin
According to the research team led by Xing Lida from China University of Geosciences (Beijing), the research indicates that the Sihui Museum specimen nests within a grade of North American Lambeosaurini and forms a sister taxon relation-ship to the clade containing
H. altispinus,
V. coahuilensis and
M. laticaudus.
Hypacrosaurus stebingeri forms a sister taxon to the most recent common ancestor of
H. altispinus and Sihui Museum specimen.
Velafrons coahuilensis and
M. laticaudus are sister taxa.
The Sihui Museum specimen is the first lambeosaurine known from South China. Other East Asian lambeosaurines include
Nipponosaurus (Russia),
Tsintaosaurus (East China),
Amurosaurus,
Sahaliania and
Charonosaurus (Northeastern China and Russia). The topology of the cladogram supports an initial dispersal of more derived members of Lambeosaurini from Asia to North America, and a clade uniting
Corythosaurus,
Hypacrosaurus,
Velafrons and
Magnapaulia is estimated to have evolved in North America. The nesting of the Sihui Museum specimen within this clade suggests that this more derived clade of lambeosaurins migrated from North America back into Asia, likely across the Bering Strait.
The ceratopsid
Sinoceratops is an Asian taxon likewise nested among North American forms and provides similar evidence to this end, Xing, associate professor at the China University of Geosciences (Beijing), told the Global Times.
However, the Sihui Museum specimen is the only migrant whose paleogeographic distribution has expanded into South China, according to Xing's team.
Housed in the Sihui Museum, the new lambeosaurine is from the same region as the tyrannosauroid teeth.
Iliac bones of the Sihui Museum specimen
The research team described a fragmentary skeleton of a duck-billed dinosaur from the same general region. The specimen consists of a scattered postcranium from a single individual (based on similarity in size and non-overlapping elements).
Diagnostic features of the dorsal vertebrae and pelvis allowed the research team to further identify this as a member of the tribe Lambeosaurini, which is otherwise poorly represented in the Chinese fossil record and, before now, unknown from South China.
Fossil hunter Zhao Canhui found both the lambeosaurine specimen and the tyrannosauroid teeth at a construction site in Taipinggang and donated them to the Sihui Museum. Despite belonging to a single individual, each bone from the lambeosaurine specimen has been given its own catalogue number at the Sihui Museum, the research stated.
The research team described the bones of this animal, which signifies the first occurrence of the tribe Lambeosaurini in South China.
The skeleton includes dorsal and caudal vertebrae, a humerus, ilium, femur and tibia.
Morphological comparison and cladistic analyses support that this specimen belongs to the tribe Lambeosaurini. The new specimens and the previously discovered tyrannosauroid teeth represent the dominant taxa of the typical Late Cretaceous dinosaur fauna of Laurasia, researchers said.
