Bone Modification

Paleoecology and paleoenvironment can be determined by examining bone modification to the carcass. The more obvious and most remarked upon modifications are tooth marks (McClain et al. 2018) as these provide a useful source of information as to the potential trace-maker. However, the causes and effects of bone modification should be examined for behavioral interpretations as well (Jacobsen and Bromley 2009). The pre-burial history of the specimen must also be studied to elucidate possible scenarios that may have caused bone modifcations before death, at the time of death, or thereafter.


There are areas of deeply eroded articular surface on the ischium and femur that appear pathologic. On the ischium, the proximal articulation has a groove 1.5 cm deep, 10 cm long (Fig. 20). The lateral condyle on the distal end of the femur as has a circular, deep depression (Fig. 21). Future work includes internal analyses using the vanguard of new X-ray technologies such as CT, XMT, MRI, as well as synchrotron imaging to allow a high-resolution three-dimensional approach to diagnosing this observation and examining the associated histology.

The femur and tibia have a variety of tooth mark traces, some that penetrated and damaged the periosteum while other traces left tooth strike marks that did not penetrate. There is a group of three parallel tooth marks, cf. Knethichnus paralleum (Jacobsen and Bromley 2009), spaced approximately 20 mm apart on the surface of the left femur and measure 40 mm long (Fig. 21). There is another set of Knethichnus paralleum that are smaller and more narrowly placed bite marks 10 cm away from the larger set. The left tibial shaft shows a very large single tooth strike that has not penetrated the cortical bone but has left an elongated, shallow groove or indentation.

Full report

Sharing the science

We’re pleased to be able to share Preliminary Scientific Reports to help visitors who come to see these incredible T. rex understand more about them.

These reports are prepared by two of the world’s top therapod paleontologists, Dr David Burnham (University of Kansas Biodiversity Institute and Natural History Museum) and Dr John Nudds (Department of Earth and Environmental Sciences, University of Manchester), who have studied both Peter and Barbara in their university laboratories for many months. Their research has identified the unique pathologies of each specimen, such as the injury to Barbara’s leg and the marks on Peter’s leg. As these reports are preliminary, they’re not peer-reviewed yet.

It’s not standard practice for a museum to share this much information when a specimen is being exhibited for the first time, but with the benefactor’s agreement we’re keen to share the initial findings, to enhance the learning experiences that having these two specimens in our Museum provides for the people of Aotearoa New Zealand.

Updates to the Preliminary Scientific Reports will be an ongoing process and will most likely span decades, rather than years.