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Zygorhiza ("Yoke-Root") is an extinct genus of basilosaurid early whale known from the Late Eocene, 38–34 MYA of Louisiana, Alabama, and Mississippi, United States.

Zygorhiza kochii is the state fossil of Mississippi. The mounted specimen in the Mississippi Museum of Natural Science in Jackson is commonly referred to as "Ziggy".

Like other dorundontines, Zygorhiza had a body similar to modern cetaceans with flipper-like forelimbs, rudimentary hind limbs, a vertebral column adapted for oscillatory swimming, and a tail fluke.

Marino et al. 2000, estimated the adult body mass for Zygorhiza to 3,351 kilograms (7,388 pounds) based on an estimated body length of 5.2 meters (16.6 feet).