Australasian Science: Australia's authority on science since 1938

The Amazing Dinosaur Tracks of Broome

By John Long

The discovery of a diverse range of dinosaur tracks fills in a huge gap that tells us what kinds of dinosaurs once inhabited Australia during the first quarter of the Cretaceous period.

In March, a landmark publication in Australian palaeontology was published – 152 page monograph in the Journal of Vertebrate Paleontology supplement series detailing over 20 species of different dinosaur trackways left in130-million-year-old coastal sandstones exposed from Broome to the lower Dampier Peninsula (http://tinyurl.com/mqansao).

Dr Steven Salisbury and his team of students at The University of Queensland have been working the sites since 2011 to map and capture the footprints using a variety of modern approaches, such as drones for accurate aerial photography of the trackways, which are often only exposed for brief times at low tides. The use of colour photogrammetry to bring the prints to life in stunning 3D is a visual highlight of the work.

In all they have recognised a range of trackways belonging to as many as 21 different dinosaurs, with six new track types formally named. Among these are a theropod trackways (Yangtzepus), a new sauropod track (Oobardjidama) and two taxa belonging to thyreophorans (Garbina, Luluichnus), a group containing well-known ankylosaurs and stegosaurs.

The work is careful not to overstep the mark and give new names to every different trackway. The giant sauropod trackways are thus represented by one new named type and five other trackway types (A–E) plus records of additional prints that could represent other species.

The new work builds upon the previous studies at the sites by others, including Dr Tony Thulborn and the late Tim Hamley, who were also based at The University of Queensland, and myself, who made a short investigation of the sites with the late Paul Foulkes back in 1990. Thulborn’s paper on sauropod tracks of the region in 1994 was the first to document very large sauropod tracks up to 1.5 metres long. The new research shows even larger tracks, around 1.7 metres long, making them the largest-recorded dinosaur print known anywhere. Such sauropods must have been gigantic titanosaurians measuring 25–30 metres in length.

However, it is the high diversity of trackways recorded at each of the four main sites that makes the region a world-class scientific site, far surpassing even the richest-known dinosaur track sites anywhere on the planet. As most of our well- known dinosaurs were found from sites from the latter half of the Early Cretaceous (100–125 million years ago), the new research also fills in a huge gap telling us what kinds of dinosaurs once inhabited Australia during the first quarter of the Cretaceous period 145–125 million years ago.

In recent years there was major controversy over protection of the dinosaur tracks while plans for a major gas-processing plant were developed to be built at one of the main trackway sites. At the time, the scientific work on the tracks was just underway. The gas plant plans did not go ahead, partly due to the publicity generated by Salisbury showing how significant the tracks were, and also by indigenous leaders who publically proclaimed how important the track sites were to their local heritage. The paper by Salisbury and his team not only describes the scientific significance of the dinosaur trackways within their geological context, but also presents a detailed account of the history of the site’s discovery together with the local indigenous history, stories and values embodied by the tracks.

The appendix gives a good account of the controversies over the theft of “stegosaur” prints from the site in late 1996, which was front page news in The Australian at the time. As a curator at the Western Australian Museum I assisted in police investigations of the theft. Despite our fruitless searches to recover the missing prints, outlined in my book, The Dinosaur Dealers (2002), the mystery has now been resolved. Salisbury’s team found that prints were not stolen, as first thought, but had been damaged by natural weathering. They were found in pieces near the site, and have since been glued together and returned to their original place in the trackway.


John Long is Strategic Professor in Palaeontology at Flinders University, and is current President of the Society of Vertebrate Paleontology.