MSU paleontologists excavate dinosaur clutches in China

Montana State University paleontologists recently excavated four clutches of dinosaur eggs in China and found at least four more clutches they may excavate in the future. 

David Varricchio, Frankie Jackson and two Chinese colleagues (from left) jacket a clutch of dinosaur eggs from a little outcrop of badlands. Since many areas of southeast China are covered with thick vegetation, the paleontologists looked for field sites that were more open [Credit: Frankie Jackson]

The discovery is unusual for an area where it's hard to find fossils because the vegetation is so thick that it resembles Georgia more than Montana, said assistant research professor Frankie Jackson. 

"We were relieved to find eggs," Jackson said. 

The discovery may also shed light on a huge collection of dinosaur eggs that Montana college students are analyzing in a related three-year collaboration with China, said Jackson and associate professor of paleontology David Varricchio. 

Jackson, Varricchio and MSU graduate students Jade Simon and Ashley Poust traveled to the Hangzhou area of southeast China in December through a National Geographic grant that funded one month of fieldwork. 

Working with a crew from China, the paleontologists excavated two clutches along road cuts and two clutches in more remote areas near agricultural fields. One clutch held four dinosaur eggs. The others each contained at least seven eggs. 

The eggs in one clutch are unusually small -- a little over 1.5 inches long, Jackson said. The eggs are also three-dimensional, unlike many dinosaur eggs found in Montana, which are often crushed and flattened during fossilization. The difference between fossil preservation in Montana and China is one thing the paleontologists want to study. 

Ashley Poust, Jade Simon and Chinese colleague Wenjie (from left) examine dinosaur eggs after a day in the field [Credit: Frankie Jackson]

Excavating the clutches was valuable in itself, because knowing how eggs are oriented in the clutches, what kind of sediment or rock surrounded them, and the geochemistry of the rock can provide the paleontologists with important context, Varricchio said. 

The context might offer clues as to why the dinosaur eggs in China are preserved so differently than the dinosaur eggs in Montana, Varricchio said. 

The clutches could also yield discoveries about dinosaur behavior or parental care, a topic of particular interest to Varricchio and Jackson who published, among other things, a 2008 paper in "Science" that said males representing three types of dinosaurs were sole care givers for their mate's eggs. 

The "super dads" may even have had multiple mates and watched all their eggs at once. Varricchio and Jackson also hosted the Fourth International Symposium on Dinosaur Eggs and Babies in 2009. 

The next symposium will be held this year in Hangzhou, the same area where the MSU team excavated the clutches and the same place that Montana college students have analyzed dinosaur eggs the past two summers. 

This illustration shows a Troodon attending his clutch. Large clutches suggest that males protected and incubated the eggs from perhaps several females [Credit: Bill Parsons]

The National Science Foundation is funding a three-year program providing international research experience for students. This program began in the summer of 2010 and sends nine students a year to conduct research in China. The undergraduates who are chosen for the expedition attend MSU or other colleges in Montana. They go to China to examine thousands of dinosaur eggs in the collections of the Natural History Museum in Hangzhou. Many of these eggs have unusually thick, but porous shells. 

The paleontologists believe the eggs may have been laid by carnivorous dinosaurs, but they don't know yet why the eggs are so thick, yet porous. Understanding that could be significant because porosity in modern eggs is tightly correlated with the incubation environment and the physiology of the embryo. Understanding the incubation environment, however, may prove difficult in this case. 

"There are no comparable eggs today -- reptile or bird," Jackson said. 

Those eggs and the newly excavated clutches are all housed at the Natural History Museum in Hangzhou, but the MSU paleontologists who went to China in December brought small samples of eggshell back to MSU to analyze. They said undergraduate students who travel to China through the NSF international research grant will most likely incorporate those samples into their work, too. 

This is the bottom view of a Troodon clutch with 22 eggs [Credit: MSU's Museum of the Rockies]

The December fieldwork complemented the undergraduate research funded by the NSF, the paleontologists said. Varricchio and Jackson lead the NSF project. 

Varricchio will lead this year's group of students to China. Now in the process of being selected, the students will leave Montana in mid-May and return in June. While in China, they will spend part of their time in the laboratory, part of the time in the field and part of their time experiencing the Chinese culture. They also join paleontology staff from the Zhejiang Natural History Museum during field exercises. 

Varricchio and Jackson said students involved in previous expeditions have already presented some of their findings at conferences, and they are preparing papers for publication. They have applied for funding through MSU's Undergraduate Scholars Program for additional research. 

Author: Evelyn Boswell  | Source: Montana State University [February 08, 2012]