What’s on the van? – Shark tooth fossil

This week’s What’s on the van? comes from Paul Jeffery, assistant curator of the Museum’s Geological Collections.

The oldest known collection in the Museum is that of Edward Lhuyd (1660-1709), made during the 1680s-1690s. This collection formed the basis for Lhuyd’s ground-breaking monograph, Lithophylacii Britannici ichnographia – a systematic illustrated catalogue of the collection of fossils he was responsible for as Keeper of the Ashmolean Museum, which at that time was still based in its original building, now the Museum of the History of Science in Broad Street.

Lhuyd’s book set the framework for later works by authors such as Carl Linnaeus (1707-1778) and Gustavus Brander (1720-1787) who further systematised the naming and description of animals, plants and fossils, and introduced a Latin-based naming regime still used today.

Lhuyd also advanced thinking on fossils, recognising them as organic in origin, rather than spontaneous mineral concretions or sports of the devil. This was daring and radical for its time – an era when religious orthodoxy still strongly influenced philosophical and academic thought.

This particular shark’s tooth comes from the extinct species Otodus obliquus. It is from the 50 million year old London Clay (Early Eocene), and was found on the Isle of Sheppey, Kent. Such teeth can still be found on the beaches there today, washed from the crumbling clay cliffs by rain and wave alike.

It is an uncommonly large species of shark – teeth may exceed 75mm in length, and represents one of the earliest steps in an evolutionary “arms race”. During the Palaeogene and Neogene this lineage of lamniform sharks evolved ever larger and more comprehensively serrated teeth, along with proportionately increased body sizes, to keep pace with early whale evolution, as they too increased from modest proportions to the giants of today.

It was a race the whales eventually won in the Early Pleistocene. Otodus’s descendant – the giant Carcharocles megalodon, a 20m long super-predator – disappeared around this time: outgrown by the whales, out-competed by new predatory species and displaced by global climatic cooling.

We will be exhibiting some of Lhuyd’s fossils in Natural Histories, a collaborative exhibition based at the Museum of the History of Science, opening on 14 May. More information about this will follow very shortly.

Paul Jeffery, Assistant curator of Geology