The month of May that we’re living in is very different from the one we all anticipated at the start of the year. However, society somehow manages to march on. College students are still graduating, moms are still being celebrated, and Mesozoic Monthly continues! Our honoree for the month of May is known to have been a dedicated parent due to several specimens that show adults guarding eggs. Say hello to Citipati osmolskae!
A devoted Citipati parent guarding its nest. Some evidence suggests that the Citipati skeletons found atop nests may have been males (rather than females as was originally thought). Also, recent research indicates that—believe it or not—oviraptorid eggs were blue! Art by ginjaraptor on DeviantArt.
It might not look like it, but Citipati is a theropod, like the more famous dinosaurs Tyrannosaurus, Allosaurus, and Velociraptor. Most theropods were carnivores, sporting skulls with big toothy grins, but not all theropods were ravenous predators! There are several groups of theropods that evolved toothless beaks for specialized diets. One of the stars of Jurassic Park, Gallimimus, was part of a predominantly herbivorous group of beaked theropods called Ornithomimidae. Citipati belongs to another group of beaked theropods called Oviraptoridae. “Oviraptor” means “egg thief,” in reference to an old hypothesis that oviraptorids stole and ate eggs from other dinosaurs’ nests. The discovery of a Citipati skeleton perched in a brooding position atop a nest of eggs was pivotal in changing this idea. We now know that instead of stealing others’ eggs to eat, fossilized oviraptorids preserved near eggs were actually protecting their own eggs! The eggs in an oviraptorid’s nest were arranged in circles with a space in the center for the parent to sit and spread their feathered arms over their incubating young.
Citipati and other oviraptorids are closely related to one of Carnegie Museum of Natural History’s most bizarre dinosaurs, the ‘Chicken from Hell’ Anzu wyliei, shown here on display in the museum’s Dinosaurs in Their Time exhibition.
So, instead of eggs, what would the toothless beak of Citipati have been used to eat? Because most oviraptorid beaks are very deep, like those of modern parrots, most paleontologists infer that these dinosaurs ate mostly plants. However, this doesn’t necessarily mean that meat was off the menu; it would still have been possible for oviraptorids to have eaten small animals, making them omnivores. On top of its thick skull, Citipati possessed a tall, triangular crest that gave its small head a square-shaped profile. This crest was not as impressive as those on some other dinosaurs, but since Citipati grew to ten feet (three meters) long, the animal would still have been quite imposing. I certainly wouldn’t want to get between a Citipati parent and its eggs!
Citipati fossils are found in the modern Gobi Desert of Mongolia, in rocks known as the Djadokhta Formation. The Djadokhta rocks are made of sediments that were deposited late in the Cretaceous Period, preserving details of the ecosystem that existed there roughly 80–75 million years ago. The name Citipati means “funeral pyre lord,” which is fitting due to the hot environment in which this oviraptorid lived. Also, Citipati shares its name with a Buddhist deity that is believed to protect cemeteries from thieves, which is an appropriate parallel considering how the skeleton of this dinosaur was found guarding its fossilized nest.
Although the habitat Citipati lived in was a desert, like the Gobi Desert that is there today, this prehistoric desert was probably not as dry. In the event of rain, water gathered in temporary streams that drained the water to basins and oases. Since desert rain events are by definition few and far between, any animals that did not live near these oases would have needed to have adaptations for going without water for a long period of time. Some of the animals that lived in this unwelcoming environment alongside Citipati included everyone’s favorite small theropod Velociraptor, the hornless ceratopsian Protoceratops, and the tail-club wielding ankylosaur Pinacosaurus.
Lindsay Kastroll is a volunteer and paleontology student working in the Section of Vertebrate Paleontology at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.