Unlocking Hidden Secrets of Fossil Teeth

21st Century Investigation Meets “Ice Age” Fossils

By Dr. Simon Jackson, Collections and Learning Curator, Ipswich Museums

Modern scientific techniques are helping us to unlock the secrets of fossil teeth, and to provide new insights into these creatures’ lost worlds. Today, we feature Laura Hemmingham, PhD student at Royal Holloway University of London and the Natural History Museum in London who visited the Ipswich collections (13-15th September 2021) to study our nationally significant “ice age” mammals; specifically the teeth of deer.

Fossil teeth are a key to understanding an animal’s diet. You are probably quite aware that different animals have different shaped teeth depending on their diets; no doubt you are familiar with the large, piercing canines of the mammalian Carnivora, such as tigers, or perhaps the large crushing, flat oval surfaces of elephant molars. Hence, obvious deductions can be made from studying fossil teeth of animals to infer what they ate.

Scientific techniques¹ (called mesowear analysis) involve studying the height or sharpness of the points or cusps of teeth (molars); the more abrasive a particular type of food is e.g. grass, the lower or rounder the points will be and the less abrasive a food is the higher and sharper the points will be. And these measurements can be made with the naked eye.

Perhaps more cutting edge (if you’ll excuse the teeth pun!) is the dental microwear analyses. This is where we can study the surface of teeth under magnifications up to 35 times, to study their scar pattern. More abrasive wear, for instance, that coming from grasses, generate more scratching, whereas pitting on the tooth is generated from eating softer foods, like browse (e.g. leaves, twigs). Undertaking such an analysis, however, involves quite a long, and somewhat fiddly process…

Laura Hemmingham, PhD student, creating moulds from Ipswich Museum’s deer teeth for study. Laura is studying at the Royal Holloway University of London and the Natural History Museum, London.

Laura sits at the desk littered with a ‘sea’ of fossil teeth, including an almost complete skull of a giant, extinct deer. The mandible (lower jaw) of one deer is held firmly in her left hand, and in the right she grasps, something which looks like a science-fiction-movie laser gun, which is in fact a silicone putty gun. As the trigger is gently squeezed, a bright, sky-blue, thick paste oozes out of the needle-like nozzle onto the surface of the lower jaw. The bright blue, almost serene, colour is in complete contrast to the ‘warm’, dark, chocolate-brown of the 500,000+ year old fossil. In a matter of minutes, the blue putty sets, forming a rubbery, but still glistening mould. In time, Laura will take it back to the Royal Holloway lab and infill the mould to produce a cast. There, its destiny will be fulfilled as its analysis will provide the key to unlocking the animal’s diet.

A mould of one of the deer molars, created by Laura Hemmingham, PhD student from Royal Holloway University of London and the Natural History Museum, London.

So what does Laura want to investigate? Laura is working across a range of collections across Europe, including ours. Each individual tooth provides an insight into what that animal was eating before its death, each like a piece of the jigsaw. The whole jigsaw is made by putting the pieces together; we can then see patterns of how deer diet changed over time and across a range of environments across ice age Europe. The British Isles is a particularly good place to study the changing fauna during the last ice age; we must remember that the ice age is not one cold period but actually consists of many cycles of colder and wetter and warmer periods. Additionally, Ipswich Museum enables us to go back even further (2.5+ million years ago) to a period just before the ice ages (through its East Anglian crag material). Perhaps if we can understand how these ancient deer adapted in the past to warming and changing environments, we might have a better understanding of what could happen to them in our projected warmer world future?

Laura leaves. The strange, almost surreal-blue moulds in tow. The fossils sit motionless on the curatorial table. But in time, through Laura’s research, life will be breathed into the lives of these fossil creatures, their diets, and dynamic environments. They are a silent witness of sorts to the lost worlds of our recent ice ages.

Footnote

1. Although Laura’s research detailed here, is new, it uses existing techniques developed recently. The mesowear method she uses is from Mihlbachler et al., 2011, developed from earlier techniques of Fortelius and Solounias, 2000; Rivals et al., 2007. The microwear method she is using was initially developed around 20 years ago by Solounias and Semprebon, (2002). Ipswich Museum has a strong track record of contributing and supporting this research. For instance, in 2016, a study co-authoring Professor Adrian Lister from the Natural History Museum, included some 54 of our specimens including bison, ancient horse (Equus ferus) and most uniquely, the only specimens of the first European mammoth (Mammuthus rumanus) from the older Red Crag, in order to infer the diet of these ancient animals.

References

• Fortelius, M. and Solounias, N. (2000). Functional Characterization of Ungulate Molars Using the Abrasion-Attrition Wear Gradient: A New Method for Reconstructing Paleodiets. American Museum Novitates, 3301, 1-36.
• Mihlbachler, M., Rivals, F., Solounias, N. and Semprebon, G. (2011). Dietary Change and Evolution of Horses in North America. Science, 331, 1178-1181.
• Rivals, F., Mihlbachler, M. and Solounias, N., 2007. Effect of ontogenetic-age distribution in fossil and modern samples on the interpretation of ungulate paleodiets using the mesowear method. Journal of Vertebrate Paleontology, 27, 763-767.
• Rivals, F., & Lister, A. M. (2016). Dietary flexibility and niche partitioning of large herbivores through the Pleistocene of Britain. Quaternary Science Reviews, 146, 116-133.
• Solounias, N. and Semprebon, G. (2002). Advances in the Reconstruction of Ungulate Ecomorphology with Application to Early Fossil Equids. American Museum Novitates, 3366, 1-49.