Fossil Fish of the Moenave

Fossil fish scales in piece of Moenave, with penny for scale
Fossil fish scales, Zion Museum Collection: ZION 667

NPS photo / Scott Ireland

The rivers, deltas, and lakes of the early Jurassic period were home to the 200 million year old fish Lophionotus. Lophionotus is an extinct species of ray-finned fish from the late Triassic and early Jurassic. The fish were fairly widespread, inhabiting lakes throughout the area that is now Utah and Arizona. These fossil fish were formerly thought to be of the genus Semionotus, but a recent name change to Lophionotus separates the fish found in this region from similar, related fish in the Newark Basin of New Jersey.

The Whitmore Point member of the Moenave Formation preserves fragments of bones and scales of Lophionotus, and the Zion museum collection houses a large impression of the fish's skin, preserved in the red mudstones. This specimen is important, because although widespread and abundant, many Lophionotus fossils are fragments or partial remains, so the species is not well understood. Evidence from dinosaur and fish fossils recovered at the nearby St. George Dinosaur Discovery Site at Johnson Farm indicated that these fish may have been a regular meal for early Jurassic predators like Dilophosaurus.

Learn more about the Moenave Formation

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Last updated: July 6, 2015

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