Calgary — A study conducted by researchers at the University of Calgary showed that dinosaur’s nesting styles may have a direct relation with the success of evolution of modern birds. The findings were published in the journal Plos One.
The research makes emphasis in the relation between the porosity of dinosaurs eggshells and nesting types, such as burying eggs and open nests.
“Nest structures are usually not preserved in the fossil record, making it difficult to determine if dinosaurs buried their eggs during incubation like crocodiles, or if they were incubated in more open nests as in brooding birds. There are many papers that seek the incubation method of dinosaurs, but our research is one of the most comprehensive studies in that it analyzes large datasets on the eggs of both living and fossil species,” said Kohei Tanaka, co-author of the study.
For the research, Darla Zelenitsky, an expert on dinosaur eggs and nesting sites, helped Takana and his team to study the porosity of the fossilized eggshells of 30 dinosaur species, which they compared to that of 120 different species of crocodiles and birds.
According to Tanaka, fossil eggs are more challenging to study since fossil specimens tend to be incomplete. However, he says that some of the eggshell’s microscopic features are preserved, like the porosity, which can suggest the nesting style dinosaurs had without having a complete nest fossil available.
While crocodile and megapode bird eggs have a high porosity and are incubated in buried nests, bird’s eggs are incubated in open nests and have low porosity. Given that a majority of dinosaurs — including sauropods, ornithischians, and primitive theropods — laid high porosity eggs in order to help the distribution of carbon dioxide and oxygen and simultaneously allow the escape of water vapor, it is most probable that they buried their eggs like crocodiles do.
The result was different in the case of small meat-eating dinosaurs, though. The level of porosity in their eggs seemed to diminish. The eggs of more advanced dinosaurs like theropods, the modern bird ancestors, also seemed to show low porosity, indicating that they might have incubated their eggs in open nests.
Scientists suggest that some dinosaurs which went by the open nesting style still buried their eggs sometimes, a factor that could have protected them from predators, helping them on their evolution process.
Researchers explain that the open nesting style didn’t occur fully until modern birds appeared, and so, as dinosaurs evolved into birds, their nesting styles were progressively adapting as well.
Tanaka said that for a better understanding of dinosaurs’ nesting habits, further discoveries of fossil eggs are needed. He and his team plan to continue their research on the evolution of nesting styles, as well as the time it took dinosaur eggs to hatch.
Source: Fox News