You Should Fear and Respect the Radula

Jim has decided that he will join the darkside for the Invertebrate Battle Royale. That’s fine! We wouldn’t want someone with such poor cognitive processes on our team. Jim’s attack centers on the idea that the Aristotle’s Lantern is cooler than the radula.

Now I just cannot stand for this. Especially after reading about how the molluscan radula is deemed one of the reasons this phylum is so cool compared to the echinodermata. I’m sorry, but Craig must not be thinking clearly. The radula? A spiky ribbon makes molluscs cool? Please. Don’t waste your time, Craig. If we’re going to be comparing feeding apparatuses (apparati?) of molluscs and echinoderms, your precious mantle-wearing protostomes don’t stand a chance. Echinoderms utilize one of, if not the, coolest feeding mechanism in the animal kingdom – Aristotle’s Lantern.

You can head over to Jim’s waste of server space to read all about. Let me save you the trouble. Aristotle’s Lantern is just an overly complex (50 skeletal elements and worked by 60 muscles, big deal) structure. The whole thing is just 5 glorified ice-scrappers bound together with a little connective tissue. The function is nothing more than scraping with the exciting part being that it can be used to scrape algae off rocks, scrape dead material off the mud, scrape…you get the picture. For all that complexity all it does is scrape and nothing else.

conus_zahn.jpgThe radula on the other hand…is a design marvel in its simplicity and adaptability. There are seven basic types (with variants on each) that vary in number, arrangement, and structure of teeth: docoglossan or stereoglossan radula; rhipidoglossan radula; hystrichoglossan radula; taenioglossan radula; ptenoglossan radula; stenoglossan or rachiglossan radula; and the toxoglossan radula. Needless to say all this variety allows gastropods to scrap algae off rocks AND feed on detritus AND be predatory carnivores AND be scavengers AND be parasites. Those small holes you find on shells at the shore are from radula of a predatory snail boring through the shell. The snail injects the prey with a digestive enzyme cocktail dissolving the prey within the shell into a prey slurry which is then sucked out…but I digress. Species of the family Conidae can attack ADULT fish with a specially modified radula tooth that serves as a harpoon (right). Echinoderms only relationship to ADULT fish is being their prey.

So again Mollusks are much cooler than Echinoderms.

Dr. M (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (, a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.

3 Replies to “You Should Fear and Respect the Radula”

  1. Ok, so the radula is more adaptable than Aristotle’s Lantern, but does that make it cooler?

    You did forget to mention another cool thing about radula bearing molluscs, chiton’s have the most hardcore radula of all. Their’s is coated with the mineral magnetite for super hard teeth! Beat that urchins. But holothurians of genus scotoplanes are still better than either, hands down.

    I want to see members of polychaeta battle it out.

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