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Cephalopod Radula under the SEM


Staff member
Sep 4, 2006
Cephalopod Radula under the SEM
an ongoing undergraduate advanced research project 2017-2018 Sam Mejia Evergreen State College
(full paper linked)
In most classes of molluscs, the radula is a specifically unique feeding organ that serves as a grinding mechanism to tear apart food into smaller pieces. In cephalopods, the radula consists of symmetrical rows of 7-9 teeth. The radula is most often studied using a scanning electron microscope (SEM) to observe the three-dimensional relationships between the rows of teeth.

The diet of each of these species differ entirely. Being the largest of the three, D. gigas feed on micronektonic prey such as other smaller squids, crabs, fish, and krill. Next in size, V. infernalis feed on organic debris that sink down from the ocean surface. D. opalescens, the smallest of the three species, feed on polychaetes, crustaceans, and small fishes.

Both D. gigas and D. opalescens has a heterodont radulae, while V. infernalis feed has a homodont radula. This research helps support findings that V. infernalis does not feed on micronektonic prey, but “marine snow”.

Further research should compare more cephalopod species, especially in order to find any relationship between predator and prey. More research should go into comparing the size and function of each tooth, as well as the function or purpose of marginal plates. There is a lot more research to be done in regards to cephalopod radulae.

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