Born This Day: Nicolaus Steno
Jan. 10 – Nov. 26, 1686
Steno (a.k.a. Niels Steensen, or Stensen) was a Danish geologist and anatomist who first made unprecedented discoveries in anatomy, then established some of the most important principles of modern geology.
He was Danish royal anatomist for 2 years.
Interested by the characteristics and origins of minerals, rocks, and fossils, he published in Prodromus (1669) the law of superposition (if a series of sedimentary rocks has not been overturned, upper layers are younger and lower layers are older) and the law of original horizontality (although strata may be found dipping steeply, they were initially deposited nearly horizontal.)
It also became connected with evolution theories like Charles Darwin‘s, where certain geological layers are connected to fossils of animals and plants of definite epochs (especially to ‘index fossils‘), and these organisms’ evolution as time goes by.
Steno played a role in studying recent sharks and their relationship to fossil ones:
The fourth and greatest period of Stensen’s research began in Florence at the end of October 1666, when he received the head of a gigantic Carcharodon rondeletii that had been caught near Leghorn.
He made acute observations of its skin, its canals, the brain and nerves, the Lorenzinian ampullae, and the eyes.
The rows of pointed teeth in the mouth, however, led him to a thorough study of their number and substance and also placed immediately before him the question of the relation of these teeth to the so-called glossopetra or tongue-stones, which were common on Malta and were considered lapides sui generis.
Stensen concluded that they were fossil shark’s teeth. This led to his paleontological, geological, and mineralogical discoveries.
Recently discovered walking shark of New Guinea: here.
Whale shark in US aquarium: here.