Glossopetra, meaning tongue stone and referring to petrified tooth of shark

The compositum glossopetra is derived from the Greek words glossa and petra for tongue and rock, respectively. The word glossopetra, also found in Latin texts, means tongue stone and refers to the petrified, somewhat tongue-shaped tooth of a shark [1-3]. The plural form is glossopetrae.

For centuries, glossopetrae had been found on the Island of Malta and many other places in the Mediterranean region. The Roman author and naturalist Pliny the Elder (Gaius Plinius Secundus, 23-79 AD) mentioned glossopetrae in his encyclopedic work Naturalis Historia [3]. Glossopetrae were thought to form in the ground or fall from the sky. It was not until the sixteenth and seventeenth centuries that natural philosophers made the connection between those distinctive stones and the teeth of sharks based on scientifically oriented comparison. Alan Cutler writes that the physician and naturalist Guillaume Rodelet of Montpellier noticed the similarity between tongue stones and the teeth of large sharks while he was lingering in Mediterranean fish markets: Rondelet published his shark-tooth theory in 1554, followed by a dissertation on tongue stones by Fabio Colonna in 1616 [2,4].

Fifty years later, the Danish anatomist and geologist Nicolaus Steno, who was well familiar with the ideas and findings of Rodelet and Colonna, draw his own conclusions. Steno, who had dissected the head of a huge shark brought to him at the Accademia del Cimento (Experimental Academy) in Florence, argued that tongue stones were the remains of once-living animals. Like his contemporaries Robert Hooke and John Ray, Steno related fossils to living organisms of the past [4].  Tongue stones appear to be the key stones in seeding and shaping early research and insight in paleontology.

Keywords: etymology, paleontology, natural history

References and more to explore
[1] Biology of Sharks and Rays: Glossopetrae and the Birth of Paleontology [www.elasmo-research.org/education/evolution/glossopetrae.htm].
[2] Alan Cutler: The Seashell on the Mountaintop. Dutton (Penguin Group), New York, 2003; pages 56-58.
[3] References to fossils by Pliny the Elder [gwydir.demon.co.uk/jo/fossils/pliny.htm].
[4] Nicholas Steno (1638-1686) [http://www.ucmp.berkeley.edu/history/steno.html].