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The radula (US: / ˈ r æ dʒ ʊ l ə /; pl.: radulae or radulas) [1] is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. [2] It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus .
The buccal mass is the first part of the digestive system, and consists of the mouth and pharynx. The mouth includes a radula, and in most cases, also a pair of jaws. The pharynx can be very large, especially in carnivorous species. Many carnivorous species have developed a proboscis, containing the oral cavity, radula, and part of the ...
The radula is taenioglossate, consisting of seven teeth per row: one middle tooth, flanked on each side by one lateral and two marginal teeth. The radula is used to scrape algae and detritus. Phlorotannins in the brown algae Fucus vesiculosus and Ascophyllum nodosum act as chemical defenses against L. littorea. [19]
A snail breaks up its food using the radula inside its mouth. The radula is a chitinous ribbon-like structure containing rows of microscopic teeth. With this the snail scrapes at food, which is then transferred to the digestive tract. In a very quiet setting, a large land snail can be heard 'crunching' its food: the radula is tearing away at ...
The massive radula of the scaphopods is the largest such organ relative to body size of any mollusc (among whom, except for the bivalves, the presence of which is a defining characteristic). The remainder of the digestive system consists of a digestive diverticulum , esophagus , stomach , and intestine .
The radula comprises a chitinous ribbon with teeth arranged in transverse and longitudinal rows. [13] The radula continually renews itself during the entire lifespan of a mollusk. The teeth and membrane are continuously synthesized in the radular sac and then shifted forward towards the working zone of the radula.
Image source: Getty Images. 1. Lockheed Martin. After its stock price reached an all-time high earlier this year, Lockheed Martin and its defense contractor peers have sold off considerably over ...
However, most of other researchers do not agree that Nectocaris actually being a cephalopod or even mollusk. [140] [141] Early cephalopods were likely predators near the top of the food chain. [25] After the late Cambrian extinction led to the disappearance of many radiodonts, predatory niches became available for other animals. [142]