As a palaeontologist, going out into the field to search for fossil specimens is a crucial aspect of my work. Normally, I would go to badlands in Canada and elsewhere to look for dinosaur, crocodile, and other extinct vertebrate fossils. 

People digging for fossils in the Alberta badlands.
A field team from the Canadian Museum of Nature and the Royal Tyrrell Museum of Paleontology looking for 70-million-year-old vertebrate remains in Dry Island Buffalo Jump Provincial Park, Alberta. Image: Xiao-Chun Wu, © Canadian Museum of Nature 

My research interests are varied. I explore high mountains, dry deserts and river canyons to find the fossils of extinct marine reptiles, such as plesiosaurs and ichthyosaurs, and also look for evidence of the oldest turtles. 

Three views of a cliffside in a mountain river valley.
The same field team investigating a fossil spot on the banks of the Graham River in the deep mountains of northern British Columbia. Two views of the same cliff face—seen from afar in the centre image— which is eroding away to reveal the over-200-million-year-old fossils of marine reptiles. Image: Xiao-Chun Wu, © Canadian Museum of Nature 
Image of the Gobi Desert with an accompanying close-up view of buried dinosaur bones.
Hot, dry environments such as the Gobi Desert in Inner Mongolia, China (left) are often rich in fossils, as indicated by these dinosaur bone fragments (right). Image: Xiao-Chun Wu, © Canadian Museum of Nature 
Four photos of field team members searching steep riverbanks for fossils.
Photos of field team members from the Canadian Museum of Nature and Tokyo Gakugei University looking for Cretaceous marine reptiles along the riverbanks in Riding Mountain National Park, Manitoba. Image: Xiao-Chun Wu, © Canadian Museum of Nature 

Because of COVID-19, it’s been more than two years since I’ve looked for fossils out in the field. Fortunately, my collaborators and I had collected many specimens in the years prior to the pandemic. As a result, my daily work has not been affected too much since I can work with this backlog of fossils. At the moment, I am studying a specimen of an alligator-like crocodylian (about 70 million years old) collected from the Late Cretaceous strata of Jiangxi Province, China. There’s only one complication: the specimen still resides in its home country. 

In order to facilitate my research here, my collaborators sent me 3D data and a cast of the crocodylian’s skull. Examining this data has led to an interesting discovery. 

3D models of the fossil skull and partially preserved body of an early alligator-like crocodylian.
The skull and lower jaw (left), and part of the body (right) of an alligator-like crocodylian from the Late Cretaceous strata of Jiangxi Province, China. Although not a true alligator, this animal is closely related to the modern group that contains alligators and caimans. Derived from 3D imaging data. Image: Xiao-Chun Wu, © Canadian Museum of Nature 

Initially, we treated the specimen as representing one individual. In February of this year, however, I realized that there were two sets of potentially unrelated shoulder bones preserved: the scapula and coracoid. Through careful comparison of the 3D images in different views, I found that their sizes appeared significantly different. To confirm this, I asked my collaborators in China to take measurements of the real specimen. Sure enough, one of the coracoids was much smaller, just about 72% of the length of the larger coracoid. 

3D models of the shoulder bones of an early alligator-like crocodylian.
An image of the shoulder bones of the alligator-like crocodylian specimen, showing a difference in the size and shape of the two pairs of scapulae and coracoids. Derived from 3D imaging data. Image: Xiao-Chun Wu, © Canadian Museum of Nature 

So, now I had a new dilemma: figuring out which pair of shoulder bones belong to this specimen. To find the answer, I compared the proportions of each bone in relation to the vertebrae from the backbone of modern crocodylians. What I discovered was that the proportions of the smaller pair are close to those observed in the skeleton of the Chinese alligator (Alligator sinensis), whereas the length ratio of the larger pair is very different. This indicates that the larger pair probably comes from another species, and was carried over by water current and buried with the smaller material. 

The study of the alligator-like crocodylian is close to being finished, thanks to technology and remote international cooperation that allowed work to continue in spite of the pandemic. The smaller shoulder bones belong to a new species that we will name shortly, as the other bones preserve enough important features to make such a determination. However, we cannot name another new species based solely on the larger pair of shoulder bones. I hope that—once we can resume fieldwork in China—we’ll be able to discover more fossils to resolve the identity of the larger animal.  

3D model of the shoulder bones of an early alligator-like crocodylian.
The larger scapula and coracoid, seen here in two different views, belong to an indeterminate species of an alligator-like crocodylian. Future fieldwork will hopefully recover more bones from this type of animal so that an identification can be made. Derived from 3D imaging data. Image: Xiao-Chun Wu, © Canadian Museum of Nature