A new study published by University of Calgary researchers has found a method of predicting the nest types of dinosaurs using extinct archosaur eggshell porosity measurements. Using this knowledge, researchers can gain more insight into the evolution of the nesting and reproductive behavior observed in archosaurs, a group that spans dinosaurs as well as modern birds and crocodilians.
"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," Kohei Tanaka, co-author of the study, said in a press release. "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."
There are two main types of nests among surviving archosaurs: open and covered. In the recent study, Tanaka and his team propose a process of inferring nest type using rigorous statistics based on large datasets of eggshell porosity and mass for 120 surviving archosaur species and 20 extinct archosaur taxa.
The study helped the team identifiy common characteristics between dinosaur nesting habits and those observed in modern alligators and birds.
"We were surprised that although previous studies on the eggs of oviraptorids suggested they were buried, our results reveal that their eggs were exposed similar to modern bird nests," said Tanaka. "Our results suggest that the change in nesting style occurred in small meat-eating dinosaurs that are closely related to birds."
Tanaka and his team hope that the proposed prediction method can help scientists in their understanding of both extinct and extant archosaurs.
"To better understand dinosaur nesting styles, however, future discoveries of fossil eggs will hopefully fill in the gaps in the dinosaur family tree where eggs are currently unknown," he said.
