By Keri Murrell
Preserved in Purbeck stone was a 130 million-years-old Iguanodon’s trackway. Mr Burrey discovered it at Paine’s Quarry, Herston between 1958 to 1961, resulting in the relocation to Periwinkle Cottage, Cotness, west of Corfe Castle. Following measurements in 1996, these became the holotype, (the specimen upon which the description and name of a new species is based) and paratypes (organism which helps to define the species). Thereafter the dinosaur was named Iguanodontipus burreyi. Where Iguanodontipus translates to Iguanodon-foot, with burreyi honouring Mr A Burrey. He obtained and preserved the footprints. Soon after in 1977, the prints were donated to the BNSS to ensure its permanent preservation.
How Do Trackway’s Form?
Trackways can form mainly in two ways.
- Firstly, the trackmaker walks along fine and moist sediment, which is firm to step on. Following this the track dries out. Hardening makes the prints resistant to further damage. Overtime, it gets covered in a different sediment. Permitting the original print to harden to rock over millions of years. This results in easily separable layers later, when the top layer erodes.
- This method relates to heavy animals, walking on soft surfaces. The animals foot pushes through the top layer, into the firm bed beneath the surface. As it lifts its foot, the top layer moves back in covering the print. This protects the track over millions of years. Erosion eventually reveals the footprints.
What Can Footprints Tell Us?
These footprints are of value offering more detail than fossils about the dinosaurs’ life. For example, how the dinosaur moves can be determined by the depth of print and distance between strides. If the footprint was fairly level but broad, it indicates the dinosaur is moving slowly. Conversely, if the toes are prominent in the print it suggests the dinosaur was running. Furthermore, if the prints are close together, the trackmaker could be running, further apart and they are walking. Additionally, tracks suggest whether the dinosaur moved bipedally (two-legs) or quadrupedally (four-legs). Anatomically, the prints sometimes contain imprints of feathers, skins patterns and muscle outlines. Behaviourally, if the trackway contains many similar prints of different sizes, it demonstrates the dinosaur’s species moved in herds. A collection of footprints surrounding tree impressions in the soil reveal that the herbivores fed communally.
