Research & Projects

My current research involves analyzing the phyllotaxis of both living and fossil conifer cones in a variety of species. I also am working on Miocene plant-insect interactions. As projects become published, I will update this section with our exciting results!

Following an earlier experiment in 2008, I picked up this line of inquiry as my Master's project at the University of Bonn. Using an experimental method designed to test how nutritious livestock feed is, I tested a wide variety of gymnosperms that had close relatives in the Jurassic to see how nutritious those plants might have been for dinosaur herbivores, particularly the giant sauropods. 

Publication

Digestibility of dinosaur food plants revisited and expanded: Previous data, new taxa, microbe donors, foliage maturity, and seasonality 

Although the living relatives of the Mesozoic flora were once assumed to constitute a nutritionally poor diet for dinosaur herbivores, in vitro fermentation of their foliage has shown that gymnosperms, ferns, and fern relatives can be as highly digestible as angiosperm grasses and dicots. Because nutritional information cannot be preserved in the fossil record, this laboratory approach, first published in 2008, provides a novel alternative to evaluate the digestive quality of the plants that were available to dinosaur megaherbivores such as sauropods. However, very few further studies have since been conducted to supplement and confirm the high fermentative capacity of nonangiospermous taxa. Here we show that the living relatives of the Araucariaceae and Equistaceae are consistently highly digestible, even between taxa and when influenced by environmental and biological factors, while fern taxa are inconsistent on the family level. These results reinforce previous findings about the high energetic potential of Jurassic-age plant families. Fourteen species of fern and gymnosperm foliage from five Jurassic families were collected in the spring and fall, then analyzed for their digestibility using the in vitro Hohenheim gas test. Equisetum, Araucaria, and Angiopteris were the most digestible genera in both seasons, while Agathis, Wollemia, and Marattia were the least digestible. The season in which specimens were collected was found to have to a significant effect on gas production in four out of 16 samples (P < 0.05). Furthermore, leaf maturity influences digestibility in Marattia attenuata (P < 0.05), yet not in Cyathea cooperi (P = 0.24). Finally, the species of the rumen fluid donor did not influence digestibility (P = 0.74). With the original data set supplemented by one new genus and four species, this study confirms and expands previous results about the nutritional capacity of the living relatives of the Jurassic flora. 

While processing a number of Miocene-age conifer cuticles in my role as a research assistant, I developed an especially delicate procedure to carefully bleach them for microscopy, after repeated failure using standard methods. Although the preservation was exceptional, the needles were prone to disintegration, necessitating the development of a gentler procedure. 

Publication

A modified, step-by-step procedure for the gentle bleaching of delicate fossil leaf cuticles

Cuticular analysis has long been used by palaeobotanists for the identification of fossil leaves, and a variety of chemical procedures has been developed to extract and prepare fossil cuticles. However, even commonly used solutions may be too harsh for the preparation of extremely delicate cuticles. Here we offer a step-by-step protocol for the preparation of fragile conifer cuticles using sodium hypochlorite, otherwise known as household bleach. Conifer needles from the Miocene lignites of the Adendorf and Hambach open-mine pits in western Germany were prepared using a mild solution of this oxidizing agent. The cuticles had proven to be too fragile for most maceration chemicals, including Schulze’s reagent, which even disintegrated the cuticles that were given a protective coating. However, it was discovered that trimming the leaf margins and damaged areas prior to a short exposure to 5–10% sodium hypochlorite solution resulted in the good preparation of the cuticle. Furthermore, this modified method allowed for the preparation of large areas of leaf. While this procedure may not be suitable for all cuticles, it is offered here as an easy and gentle method for preparing extremely delicate conifer cuticles that are destroyed by other chemicals and protocols.