Researchers have discovered a rare example of an ancient katydid species that is 50 million years old and still has its muscles, glands, digestive tract, and even one testicle. The comprehensive fossil, which is probably the first of its sort, has revealed crucial new details on the development of katydids.
The katydid is an insect from the green grasshopper family that makes a high-pitched sound with its front legs. It is good at jumping and not easy to catch. Sometimes when one of its legs is grabbed, it leaves it without hesitation to escape.
According to IFLscience news, the extinct species of Arethaea, often known as thread-legged katydids because of their limbs that resemble grass, has been given the name Arethaea solterae in honor of the main author’s former colleague and insect pathologist Leellen Solter.
“Katydids are very rare in the fossil record, so any new katydid fossil you find represents a new data point in the evolutionary history of katydids,” Sam Heads, study lead and director of the Prairie Research Institute’s Center for Paleontology, said in a statement. “Now we know that about 50 million years ago, this genus had already evolved and already had a morphology that mimics the grass in which it lives and hides from predators.”
Heads says it’s “not so unusual” to find stomach traces in specimens from this region, but after more microscopic examination, the researchers discovered signs of thoracic muscle fibers connected to the wings or flank muscles, “fat body” tissue, and even the presence of one testis.
“Part of the digestive tract is preserved, a part of the midgut we call the ventriculus,” Heads said. “There are these little tubules that all seem to connect to a round structure and that can only be a testis and accessory glands that are associated with the testis.”
Heads compared these findings to multiple dissected katydid specimens and discovered an essentially similar anatomical structure, concluding that “the testis, accessory glands, and ventriculus were all the same in modern katydids.” It really blew me away.”
The fossil’s recovery site is highly recognized for having many wonderfully preserved fossils. The Green River Formation, which spans the three states, is a well-known fossil bed that offers thorough records of the flora and animals of the area. But despite the area’s reputation, researchers were still shocked by the find.
“I was not expecting to see that kind of structure preserved in a rock compression. I’ve never seen that before,” said Heads. “To my knowledge, this is the first example of this level of preservation.”