Hymenochirus is an aquatic frog in the family Pipidae that lives in western Africa. Both adults and larvae are suction feeders, which is very unusual for frogs. As you can see from the movie, the tadpoles are quite fish-like in their feeding movements. In fact, they have indepedently evolved suction feeding mechanics that resemble feeding mechanics in fish. They are active predators that locate their prey visually and pursue it through the water before striking.
The suction-feeding event involves depression of the hyobranchial apparatus, raising of head, and extension of the tubelike mouth. Notice how the tadpole has visually fixated on the prey (a brine shrimp nauplius). These tadpoles are very small and fast; the interval between frames is 1 ms, and the grid in the background is 1 mm.
Figure a shows the same feeding sequence as in the movie above, b shows a "yawning" tadpole displaying its large round mouth opening, and c is an illustration of the movements of the skeletal elements inside that are responsible for suction feeding motions. Ceratohyals are light grey, copula (basibranchial) is medium grey, and ceratobranchials are dark grey.
See my research paper on this tadpole:
Deban, S.M. and W.M. Olson. 2002. Suction feeding by a tiny predatory tadpole. Nature 420: 41-42. 
Press Coverage of this Research
"Tiny African tadpole a big sucker to its prey" by John Roach, National Geographic News, November 7, 2002.
"Attack of the prey-sucking tadpoles" by Lee Siegel. University of Utah News Release, November 2002.
"Tadpoles kill by supersuction" Science News, November 16, 2002.
Copyright © Stephen M. Deban
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