A Rutgers-led team modeled how four mosasaur species could accelerate with one powerful tail stroke, showing how tail shape may have favored either ambush bursts or open-water pursuit. The research was published in Current Biology.
Mosasaurs were ocean-adapted lizards that lived during the age of dinosaurs. The team reconstructed the bodies of Platecarpus, Tylosaurus, Mosasaurus and Plotosaurus from fossil skeletons, then applied physics to estimate each animal’s initial surge.
Modeling a “slam-start”
The researchers called the movement a “slam-start.” In the model, a mosasaur curled its tail to one side and swept it back, pushing against the water to drive its body forward.
Because the fossils did not preserve the animals’ tail muscles, the team reconstructed them using the anatomy of living lizards, including Komodo dragons. The researchers then tested different assumptions about muscle power, tail flexibility and water resistance.
Long tails, faster bursts
Across those conditions, Platecarpus and Tylosaurus achieved faster lunges for their body size than Mosasaurus and Plotosaurus. Platecarpus was the fastest of the four, while a particularly large Tylosaurus was estimated to reach about 15 mph with one tail stroke.
That figure describes a brief modeled burst, not sustained swimming speed, and the exact speeds remain uncertain. The team found that tail-curl distance had the strongest effect on performance. Researchers said the longer, more flexible tail sections of Platecarpus and Tylosaurus would have favored ambush attacks in shallow seas, while Mosasaurus and especially Plotosaurus appeared better suited to pursuing prey in open water.
