For its previous food, an ancient maritime reptile referred to as an ichthyosaur might have bitten off far more than it could chew.

The dolphinlike creature was almost 5 meters very long, about the length of a canoe. And its stomach contained the continues to be of a lizardlike reptile termed a thalattosaur that was almost as very long: 4 meters. This is the longest known prey of a marine reptile from the dinosaur age, and may perhaps be the oldest direct proof of a marine reptile consuming an animal greater than a human, scientists report August 20 in iScience. In reality, this particular thalattosaur might have been these kinds of a large meal that the ichthyosaur died right after stomaching it.

The ichthyosaur’s blunt tooth recommend it should have favored little, comfortable prey like cephalopods (SN: 10/3/17). “Now we have definitely reliable proof expressing these [blunt] enamel can be employed to try to eat anything significant,” suggests Ryosuke Motani, a paleobiologist at the College of California, Davis. “That suggests the other species with similar tooth we discounted before … may possibly be megapredators as well.”

Motani and colleagues examined the virtually finish skeleton of an grownup ichthyosaur that was unearthed in southwestern China in 2010. The reptile, from the genus Guizhouichthyosaurus, lived all through the Triassic Interval about 240 million years in the past. On closer inspection of a big lump of bones in the creature’s stomach, Motani’s workforce found out that the past thing the ichthyosaur ate was the physique of a thalattosaur, sans head and tail. The thalattosaur remains display minor evidence of currently being degraded by belly acid, suggesting the ichthyosaur died soon following its tremendous meal.

These fossils provide “pretty superior proof that the bigger animal ate the smaller sized a single,” suggests vertebrate paleontologist Steve Brusatte of the University of Edinburgh, who was not included in the study. “If this truly is the case, it is rather gorgeous,” for the reason that the predator was not a lot larger sized than its prey — at least in conditions of size. The ichthyosaur is assumed to have been approximately seven instances more massive than the whip-skinny thalattosaur.

A 5-meter-very long ichthyosaur chowed down on the physique of a 4-meter-extended thalattosaur, minus the prey’s head and tail, as observed in this illustration. The previous report-holder for longest prey of a dinosaur-age marine reptile was a mereD.-Y. Jiang et al/iScience 2020

The researchers feel the ichthyosaur most very likely hunted, alternatively than scavenged, its meal. For one particular point, it would have been unusual to arrive throughout a full lifeless animal that no other predator experienced gobbled up, and the ichthyosaur would have had to shovel down the big meal on the seafloor — tough for an air-respiration creature.

As well as, the thalattosaur’s limbs had been nonetheless at the very least partially connected to its body, even though its tail was uncovered about 20 meters away. Experiments of how bodies decompose underwater propose that if the thalattosaur was a carcass when the ichthyosaur identified it, the prey’s limbs would have rotted off prior to its tail, the authors argue. 

Motani suspects that killing and consuming the thalattosaur might have spelled the ichthyosaur’s demise. The ichthyosaur’s fossilized overall body and head, while very well preserved, are detached from a single a further, hinting that the animal may perhaps have died of a damaged neck. The ichthyosaur could have wounded its neck although keeping the thalattosaur in its jaws and thrashing its head, which is how crocodiles and killer whales rip up their foodstuff without notably sharp teeth.

The ichthyosaur also could have hurt by itself though swallowing these kinds of big prey. “This is not a snake which is tailored to swallow a thing seriously major, so it has to swallow just like dolphins and crocodiles do,” Motani claims. That suggests swimming in opposition to its prey to shove the food stuff down its throat, or sticking its head over water and utilizing gravity to gulp the food down. “It could conveniently damage its neck executing this.”