A Juvenile American Paddlefish (image) San Francisco State University Share Print E-Mail Caption A juvenile paddlefish, just under three inches long at two months old. Fully grown American paddlefish can reach five feet (1.5 m) in length and have a protruding snout or "rostrum." A new study by researchers at San Francisco State University finds that the American paddlefish underwent a genome duplication 42 million years ago. Credit Diane Fenster/ San Francisco State University Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.