Title

A New Methodology for Determining Possible Hatching Events Within Sphereoolithus Eggs

Presentation Type

Poster

Abstract

The Zhejiang province of China has provided an astounding amount of dinosaur eggs. The Museum of Natural History in Hangzhou houses over 1,000 of these mid- Cretaceous eggs. There has been extensive debate over whether eggs exhibiting circular openings represent a hatching event, predation, or breakage and crushing due to burial or more recent weathering. Using a new method, we suggest that eggs with openings valued at ≥ the modeled value are possible hatching events.

We examined 38 Sphereoolithus eggs chosen based on three factors: (1)the observation of gleying inside the opening must not be attached to the primary shell structure, (2)the opening had to be observed within the least deformed hemisphere, and (3) it had to have clear and measurable axes in three dimensions.

Using calipers, we measured the eggs’ lengths, widths, and heights, as well as the widest and longest points of the openings. This data was used to find the potential volume of the egg and the opening size. For this, we utilized a series of previously published equations, which allowed us to determine the eggs’ volume, potential fetus size, and the minimum burrowing capacity. We compared our modeled results to our measured results and found 14 of the 38 eggs we studied fell within the predicted model.

To our knowledge, this system of modeling egg-hatching openings is the first of its kind. This method could help in distinguishing dinosaur eggs that are hatched from those eggs that are crushed by natural causes or suffer predation. This could also help identify the original position of the eggs, which is important in a region such as Zhejiang where fossil eggs are often sold to museums by the public, creating a gap in stratigraphic and sedimentological data.

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Apr 12th, 3:00 PM Apr 12th, 4:00 PM

A New Methodology for Determining Possible Hatching Events Within Sphereoolithus Eggs

UC Ballroom

The Zhejiang province of China has provided an astounding amount of dinosaur eggs. The Museum of Natural History in Hangzhou houses over 1,000 of these mid- Cretaceous eggs. There has been extensive debate over whether eggs exhibiting circular openings represent a hatching event, predation, or breakage and crushing due to burial or more recent weathering. Using a new method, we suggest that eggs with openings valued at ≥ the modeled value are possible hatching events.

We examined 38 Sphereoolithus eggs chosen based on three factors: (1)the observation of gleying inside the opening must not be attached to the primary shell structure, (2)the opening had to be observed within the least deformed hemisphere, and (3) it had to have clear and measurable axes in three dimensions.

Using calipers, we measured the eggs’ lengths, widths, and heights, as well as the widest and longest points of the openings. This data was used to find the potential volume of the egg and the opening size. For this, we utilized a series of previously published equations, which allowed us to determine the eggs’ volume, potential fetus size, and the minimum burrowing capacity. We compared our modeled results to our measured results and found 14 of the 38 eggs we studied fell within the predicted model.

To our knowledge, this system of modeling egg-hatching openings is the first of its kind. This method could help in distinguishing dinosaur eggs that are hatched from those eggs that are crushed by natural causes or suffer predation. This could also help identify the original position of the eggs, which is important in a region such as Zhejiang where fossil eggs are often sold to museums by the public, creating a gap in stratigraphic and sedimentological data.