Gill structure . Holobranch - entire gill (Figure 4.6) 3 elements: interbranchial septum, supported by gill ray, forms framework of gill 2 demibranchs on either side of septum. In shark, 9 demibranchs ...

A 325 million-year-old fossil find shows that the gill structures of modern sharks are actually quite different from their ancient ancestors.

Now, a well-preserved, 325-million-year-old shark-like fossil from Paleozoic Arkansas shows how the skeletal structure that supports the gills of a very early shark resembles bony fishes much more ...

LITTLE ROCK, Ark. (KTHV)- Sharks are usually thought of as primitive creatures, sometimes called "living fossils." But a new study of a 325-million-year-old shark fossil found in Arkansas suggests ...

A 325 million-year-old fossil find shows that the gill structures of modern sharks are actually quite different from their ancient ancestors. New Fossil Takes A Bite Out Of Theory That Sharks ...