Scientists from the University of Bristol discovered a Dinocephalosaurus fossil at China’s Yunnan province. The specimen is at least 13 feet long, with a long, slender neck that almost reaches 6 feet of longitude.
Paleontologists describe it to be similar to the plesiosaurus, which is the dinosaur that often gets associated with sightings of the Loch Ness Monster.
The discovery stands out from the usual not only because the specimen was pregnant at the time of fossilization, but also because Dinocephalosaurs appear to be viviparous, meaning that they give birth to live creatures.
A dinosaur that gives birth to live young
The discovery shows that Dinocephalosaurus are the first of archosauromorphs found to give birth to live offspring. Archosauromorphs include birds, crocodiles, dinosaurs, and even pterosaurs. This species also has one of the longest necks relative to body size of any known animal.
Apparently, giving birth to live young was advantageous for the Dinocephalosaurus because it would not need to leave its watery habitat to lay eggs on the shore, exposing the hatchlings to predators.
Researchers add in the study that reproductive adaptations help organisms produce subsequent generations, allowing them to live through the stages of evolution. They assure that giving birth to live offspring has evolved at least 115 times in lizards and snakes. Also, viviparity is “common” in a variety of extinct aquatic reptiles, such as the ichthyosaurus.
The specimen was unearthed in Bed 74 of the Dawazi section, in Luoping County, Yunnan Province, China. It was isolated into three blocks at the dig site. Then the fractures were filled out with soil which allowed researchers to carry the Dinocephalosaurus to the Chengdu Center of China Geological Survey for preparation.
Unearthing Yunnan’s Dinocephalosaurus, or LPV 30280
They named it LPV 30280, sharing characters with other Dinocephalosaurus specimens and other protorosaurs that show an elongated neck and an unusual amount of vertebrae. It was also determined that the smaller specimen in the abdominal region of LPV 30280 was an embryo, mainly because it was completely enclosed by the bigger specimen’s abdomen. Also, the embryo had its neck pointing forward, which rules out the possibility of the baby being a devoured prey, seeing that aquatic predators tend to swallow other animals head-first, an orientation maintained all the way through the digestive process.
What’s more is that in all archosauromorphs, eggshell remains become calcified, but there were no traces of eggshells near the LPV 30280 embryo. Also, it is worth noting that a membrane forms around the developing embryo, especially in viviparous reptiles, but this membrane cannot become calcified.
The discovery allowed paleontologists to understand more about the reproductive process of Dinocephalosaurus, enabling them to be classified as the “climax of aquatic adaptation of protorosaurs.”
“Reptilian eggs cannot be incubated underwater; amniote embryos in shelled eggs must exchange respiratory gasses with the environment across the eggshell, and this exchange is much slower in water than in air. Therefore, viviparity would have been highly adaptive for Dinocephalosaurus to reproduce in the sea,” noted researchers on the study.
Source: Nature