Researchers said the emblem was likely for display purposes, as it was too fragile to be used as a weapon, although it was made of solid bone without the air sacs found in other dinosaur crests. The coat of arms, perhaps horny, like the horns of a bull, was brightly colored and may have served for sexual or territorial competition or recognition between individuals.
“This is about love and life: attracting a mate, protecting the shallow waters of hot prey,” said University of Chicago paleontologist Paul Sereno, lead author of the study published Thursday in the journal Science. “What else could be more important?”
The nostrils are in a more retracted position than normal, allowing most of the nose to be submerged underwater in order to pursue swimming prey for as long as necessary while breathing normally. Additionally, the upper and lower teeth come together neatly during bite, a process called occlusion.
“Large cone-shaped teeth without serrations interlock to form a ‘fish trap,’ which is very good at penetrating the jaws of slippery fish to catch them and prevent them from slipping,” said paleontologist and study co-author Daniel Vidal of the University of Chicago and Spain’s National University of Education.
“We know that Spinosaurus mirabilis had the most extreme piscivorous adaptation of any dinosaur, so it was better at preying on fish than it was on other dinosaurs,” Vidal said.
Spinosaurus aegyptiacus fossils have been unearthed from sites in Egypt and Morocco near the Cretaceous coastline of the Tethys Sea, the precursor to the modern Mediterranean and Indian Oceans. This fact, and certain skeletal features, have led some scientists to hypothesize that Spinosaurus was fully aquatic, swimming in the open ocean and being a dive-seeking predator in marine environments.
However, Spinosaurus mirabilis fossils were discovered inland, approximately 300 to 600 miles from the nearest coastline. This fact, combined with the animal’s anatomical aspects, indicates that Spinosaurus was a shallow-water predator and not fully aquatic, the researchers said.
Sereno called the discovery of Spinosaurus mirabilis “a masterpiece of the aquatic hypothesis.”
The fossils were discovered in Jengebi, a remote region of the Sahara desert with fossil-rich sandstone outcrops surrounded by sand dunes. For the 2022 expedition, the researchers set out in a convoy from the city of Agadez and drove off-road for almost three days through desert terrain, often getting stuck in the sand.
The journey paid off, with the discovery of parts of the skulls of three Spinosaurus mirabilis and other bones, as well as fossils of other creatures.
Spinosaurus, long overshadowed in the public imagination by Tyrannosaurus, is now in the spotlight.
“This is a dinosaur event,” Sereno said.