On How Mollusks are Cooler Than Echinoderms (or anything else) Pt. 3: The Radula

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In general, among Mollusks, the mouth opens into a buccal cavity. In most classes of Mollusks, the buccal cavity contains a tongue called the odontophore. The odontophore possess multiple rows of teeth called radula that chitonous and flexible. Among Mollusks the number of teeth can range from a few to over 100,000. The size, number, and arrangement of the radula also vary considerably and often used as diagnostic tool for distinguishing species. In some gastropods the radula is used in a rasping or conveyor belt fashion and be used to drill holes through hard parts of other organisms. The image above from here is from the whelk Busycon carica (Gmelin, 1791). Below is an Apple Snail in rasping material of the side of aquarium.

Below the fold is another way gastropods feed.

Feeding in Holothurians not so cool. Most are suspension or deposit feeders. Some species extend there nasty branched, mucus-covered tentacles into the water to trap particles. Those nasty mucus and dirt covered tentacles are then put into the mouth. Other species plow through the mud using their tentacles to selectively feed on particles. Apparently, they are also picky eaters.

Dr. M (1629 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, created to facilitate research to address fundamental questions in evolutionary science. He has conducted deep-sea research for 11 years and published over 40 papers in the area. He has participated in dozens of expeditions taking him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses mainly on marine systems and particularly the biology of body size, biodiversity, and energy flow. He focuses often on deep-sea systems as a natural test of the consequences of energy limitation on biological systems. He is the author and chief editor of Deep-Sea News, a popular deep-sea themed blog, rated the number one ocean blog on the web and winner of numerous awards. Craig’s popular writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.





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