The teeth of the sea urchin are partially visible on its underside. They are part of the creature's mouth apparatus, named Aristotle's lantern. In the late 1960s, this remarkable mechanism inspired Giorgio Scarpa to build a bionic model of the lantern, with the results published in 1985 in his book Modelli di bionica.
Pino Trogu demonstrates his replica of Scarpa's model of the sea urchin (Aristotle's lantern) to Erica Hruby, Leonardo's managing editor and discussion moderator.
Giorgio Scarpa's original working drawing of his model of Aristotle's lantern (mouth of the sea urchin), showing various measurements and cross sections of the lantern's jaws.
Another drawing by Scarpa of the upper part of the jaw of the model of the sea urchin.
Pino Trogu's SketchUp reconstruction of the model's jaws and of some of the lantern's elastics' pathways.
Trogu showing moderator Erica Hruby another replica of the model's jaw, with two "rotulae" (the hinges between pairs of jaws) attached to it.
Still frame from a video by Michael Frank et al, from the University of California, San Diego (UCSD, 2018), showing their prototype of a mini-rover to collect soil samples on Mars, the design of which was inspired by Scarpa's model of the sea urchin. Videography by Taylor Wirth; used by permission.
Still frame from another video from Frank et al (UCSD, 2018), showing, side by side, the opening and closing of the real sea urchin's teeth (left); and on the right the opening and closing of the soil sampler's teeth. Real sea urchin photo by Yoshihiro Sawada; used by permission.
Left: Pino Trogu's SketchUp reconstruction of Scarpa's model of the sea urchin. Right: experimental prototype of a biopsy harvester by Jelínek et al, from Delft University of Technology and the Austrian Center for Medical Innovation and Technology (TU Delft & ACMIT, 2014). This prototype was also inspired by Scarpa' s model of the sea urchin. TU Delft's photo used by permission.
Leonardo Book Club welcomed author Pino Trogu in a live discussion of his article "Giorgio Scarpa's Model of a Sea Urchin Inspires New Instrumentation." The article describes Scarpa's bionic model of "Aristotle's lantern" the mouth of the sea urchin. The article is the featured article in Leonardo's April 2019 issue. It can be downloaded for free here: mitpressjournals.org/doi/pdf/10.1162/leon_a_01384
"The Leonardo Book Club is a series activating opportunities for [its] authors to connect with [its] readers." This live discussion took place on April 24, 2019. The video can be seen here: facebook.com/Leonardo.ISAST/videos/vb.340425992313/280823696155121
Abstract: Giorgio Scarpa (1938-2012) was an Italian designer, artist and teacher who worked in bionics, topology and rotational geometry. This article describes Scarpa's bionic model of "Aristotle's lantern" the mouth of the sea urchin. The technical literature on Echinoidea lacks a detailed study of its remarkable mouth mechanism. Scarpa's model is the only known analysis and physical analogue of the mechanism. It is a striking example of geometrical analysis and craftsmanship, bridging science and art. Built in the early 1970s and described in 1985 in Modelli di Bionica, his model has inspired designs for a biopsy harvester and for a mini-rover to collect soil samples on Mars.