Gyrodus is an extinct genus of pycnodontiform bony fish that lived in the Jurassic and Cretaceous. ==Sources== ... Found on http://en.wikipedia.org/wiki/Gyrodus
Gyr'o·dus (jĭr'o*dŭs) noun [ New Latin , from Greek gyro`s round + 'odoy`s tooth.] (Paleon.) A genus of extinct oölitic fishes, having rounded teeth in several rows adapted for crushing. Found on http://www.encyclo.co.uk/webster/G/71