A newly discovered 鲨鱼 that lived 370 million years ago had some of its teeth hidden from its prey until they clamped down, 根据一项新研究.
The research, published in Communications Biology, notes that Ferromirum oukherbouchi, a bizarre-looking shark with large eyes and a short snout, had a jaw that actually rotated to allow for the shark’s newer teeth to gnash at its prey’s flesh.
“Through this rotation, the younger, larger and sharper teeth, which usually pointed toward the inside of the mouth, were brought into an upright position,” the study’s lead author, Linda Frey, 在一个 声明. “This made it easier for animals to impale their prey. Through an inward rotation, the teeth then pushed the prey deeper into the buccal space when the jaws closed.”
In addition to its strange jaw, F. oukherbouchi was smaller than most modern-day sharks, 只是测量 13 inches long, the researchers discovered via its well-preserved jaws.
This allowed for the sharks to not only use their larger, inward-facing teeth but also use something known as suction-feeding.
“In combination with the outward movement, the opening of the jaws causes sea water to rush into the oral cavity, while closing them results in a mechanical pull that entraps and immobilizes the prey,” Frey added.
The feature increasingly became irrelevant as time went on and was eventually replaced by the jaw structure that sharks and rays have had for millions of years.
“The excellently preserved fossil we’ve examined is a unique specimen,” study co-author Christian Klug explained, adding that the type of jaw joint seen in this shark may have played “an important role” in the Paleozoic era.