Paleontologists discover ancient insect species in southeastern Utah

(Courtesy Utah State Parks) The fossil of Morrisonnepa jurassica along with a modern giant water bug, Lethocerus.

A group of scientists announced a rare find Wednesday – the fossilized remains of a giant bug that crawled around Utah during the time of the dinosaurs.

Called “Morrisonnepa jurassica,” the insect roamed the region 151 million years ago and was discovered in the same geological formation as Allosaurus and Stegosaurus.

It appears to be related to modern giant water bugs, or Belostomatidae, which prey on fish, amphibians, snakes and invertebrates. The bugs are also known for their excruciating bite.

“I picked one up when I was out fishing once,” said state paleontologist Jim Kirkland in a news release about the giant water bug. “An impressive 2-inch bug, but if it lays into you with that proboscis, you’ll drop it fast.”

Kirkland is co-author of a paper published this week in the journal Historical Biology that describes the ancient insect. Paleontologists from Argentina and Utah unearthed the specimen in 2017 at the Late Jurassic-age Morrison Formation in San Juan County. The only other insect discovered in the Morrison Formation so far was a cricket ancestor found in Colorado and described in 2011.

"We always dreamed of finding actual insect fossils in the Morrison, but until the first report in 2011 there had been nothing,” said John Foster with the Utah Field House of Natural History State Park Museum, in the release. “That report gave us hope, but still, when this specimen appeared under a microscope, mixed in with a bulk batch of unidentified plant fossil material, it was shocking to realize that we were looking at an insect abdomen and wing – and big ones.”

The fossil includes the abdomen, parts of the forewing and possibly the insect’s head. It is currently housed at the collections of the Utah Field House in Vernal.

Research of the insect was supported by the Bureau of Land Management, Utah Geological Survey, the Museum of Moab and the Utah Field House.

(Courtesy Utah State Parks) The fossil of Morrisonnepa jurassica along with a modern giant water bug, Lethocerus.

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