Presentation on theme: "Tongue Stones An Evolution Story Told by Patrick Staley."— Presentation transcript:
Tongue Stones An Evolution Story Told by Patrick Staley
Presentation Outline Legend to Science Why Use Tongue Stones to Study Evolution Parts and Features Environment Specific Evolutionary Lines
Magical Properties 'Tongue stones' were widely believed to have magical properties, most notably the ability to counter-act toxins of many kinds. To work their magic, they needed only to be held against a snake-bitten body part or plunked into a suspect glass of wine and any poisons would be quickly and irreversibly detoxified.
Folklore These were peculiar objects, often seeming eerily well-polished even when dug fresh from the ground. Their similarity to tongues led to the idea that they were the petrified tongues of serpents, a creature associated with the devil. It became a fairly common medieval practice to dip a tonguestone in a glass of wine proffered at a banquet to neutralise any poison that an enemy may have added to the drink.
Japanese Legend An entirely different legend developed in Japan, where the teeth of Carcharocles megalodon are thought to be the thumbnails of Tengu Man, a mythical mountain goblin with a Pinnochio-like long nose.
More Legends When tongue stones were first discovered somewhere high up in the mountains and far from the sea, their origin was a complete enigma. Pliny the Elder (AD 23-79), a great Roman naturalist, believed that they fell from the sky during lunar eclipses.
Saint Paul on Malta Many tongue stones were unearthed on the island of Malta. Their appearance was used as evidence to support the folklore of St Paul. While on the island of Malta AD60, Saint Paul was bitten by a snake. In a fit of anger he is said to have turned the tongues of serpents into stone.
Nicholas Steno One day in 1666 two fishermen caught a giant shark off the coast of Livorno in Italy. The local duke ordered that this curiosity be sent to Ncholas Steno, a Danish anatomist working at the time in Florence. As Steno dissected the shark, he was struck by how much the shark teeth resembled tongue stones, triangular pieces of rock that had been known since ancient times.
Petrified Teeth Today, most people would instantly wonder whether the tongue stones were giant petrified shark teeth, but in 1666 such a presumption was a tremendous leap. Few could imagine how living matter could be turned to stone, and beyond that, encased in solid rock specially if the rock were well above sea level and contained remnants of a marine organism.
Steno’s Shark Head Drawing
Why Sharks’ Teeth Fossils? Abundance Soft Tissue vs. Bone Getting Buried Time (400 million years) Opportunity (35,000 teeth per shark)
Teeth per Shark Sharks continually shed their teeth, and some can shed as many as 35,000 teeth in a lifetime.
Shark Dentition Embedded in Flesh Constant Replacement Files and Rows of Teeth
Parts of a Shark’s Tooth Root Crown Dental Band Cusplets Serrations Striations
Other Features Nutrient Grove Nutrient Foramen Longitudinal Ridges Crown Tip Crown Notch Crown Shoulder
Sides of a Shark’s Tooth Lingual Labial Mesial Distal
Dentition by Location Upper or Lower Anterior Lateral Posterior Intermediate Symphseal
Cenozoic Evolution of the Large Sharks Climatic Context Geographic Context
Cenozoic Global Temperature
Polar Ice Earth
Global Geography Cretaceous Eocene Recent
Great White Line Carcharodon carcharias Isurus hastalis Isurus planus Isurus desori