Invertebrate Paleontology Staff & Associates


Jocelyn A. Sessa, PhD

Assistant Curator of Invertebrate Paleontology
Assistant Professor, Department of Biodiversity, Earth & Environmental Science


Jocelyn Sessa is a paleobiologist who uses the fossil record as a natural laboratory to study times of change in earth’s history. Her research melds fossil and modern data to elucidate the response of mollusk faunas (clams and snails) to environmental perturbations across space and time. Sessa’s studies span a wide range of events, from the mass extinction that killed off the dinosaurs to past climatic fluctuations, including intervals of past and present global warming. By analyzing the chemistry of mollusk shells, she also reconstructs the climatic conditions that affected ecosystems.

Sessa’s hunt for mollusks is a worldwide endeavor, with fieldwork along the US eastern seaboard, the US Gulf Coast, California, Romania and Angola. An important facet of her scholarship is mentoring high school through graduate students in research projects. Sessa is passionate about making science accessible to everyone. Since 2007, she has participated in programs to engage groups under-represented in the sciences, and she is excited to continue this work in the Philadelphia Area.

For more details about Jocelyn’s work, please check out:

 scientist in white shirt in front of starfish specimen

Dr. Alejandra Martinez-Melo

Collection Manager of Invertebrate Paleontology

Alejandra is responsible for the care, maintenance, and management of the Invertebrate Paleontology collection. She obtained her Biology degree, her Masters and PhD in Marine Sciences and Limnology, from the National Autonomous University of Mexico (UNAM). After obtaining her Ph.D., Alejandra was a postdoctoral fellow at the Institute of Geology (UNAM), and at the Center of Paleontology Research (CR2P), Sorbonne University, France. Alejandra conducts research on the taxonomy, systematics, and biogeography for Post-Paleozoic Echinoids; for more details about her research, go to


Rosie Oakes, PhD

Research Associate in Invertebrate Paleontology


Rosie is an earth, ocean, and climate scientist interested in the impact of global climate change on natural and human systems. Her PhD and post-doctoral research were focused on understanding how ocean acidification, caused by increased carbon dioxide from the atmosphere dissolving in the ocean, impacted marine plankton. Rosie studied a group of tiny swimming snails called pteropods, hailed as the canary in the coal mine for ocean acidification. During her PhD, Rosie designed a method to measure the thickness of the shells of these tiny plankton to assess their risk from ocean acidification. Rosie continued to study these sentinel organisms during her three-year postdoctoral research fellowship in the Invertebrate Palaeontology department at the Academy. Rosie, along with other members of the Invertebrate Paleontology group, is leading a research project investigating how pteropods off the coast of Shetland, Scotland have been impacted by changing ocean conditions over the past 200 years.

Rosie is a Research Associate at the Academy but spends most of her time working as an International Climate Services Scientist at the UK Met Office, translating outputs from global climate models into a format that is accessible to stakeholders and decision makers around the world. Rosie’s current projects involve understanding food security in China and evaluating cross-border climate risks in Europe.

For more details about Rosie’s work, check out her website:


Wunn Noon Naw

Undergraduate Curatorial Assistant

Wunn is a freshman majoring in Environmental Science at Drexel University. She hopes her work in the Invertebrate Paleontology collection will help guide her academic path and help make her education more interdisciplinary. Wunn is excited about the hands-on experience she gets working with a large collection of specimens and wants to learn more about the different invertebrates in the collection. In her free time, she likes to volunteer, paint, and explore different restaurants in Philadelphia.


Erin Wright

Undergraduate Curatorial Assistant

Erin Wright is a sophomore environmental studies and sustainability major who is also pursuing a public health minor. She is currently on co-op in Invertebrate Paleontology, and she also works part time in Diatoms. After graduation, she sees herself working in environmental policy or compliance law.


Alexis Wiley

Undergraduate Curatorial Assistant

Alexis is a pre-junior biological sciences major concentrating in evolution, ecology and genomics. She plans on studying evolutionary biology for conservation in her future. Currently, she enjoys learning about the biodiversity represented in the fossil record through the invertebrate paleontology collection.

Alexis studied abroad in Bioko through the Drexel in Equatorial Guinea program this previous winter. In her free time, she volunteers with Students Run Philly Style mentoring high school students through running.


Kelly Rozanitis

Curatorial Assistant

Kelly is a recent Drexel geoscience graduate. University with concentrations in Paleontology and Applied Geology. Her interests include the chemistry and structure of fossils, as well as curating and caring for the collections. She has experience curating and preparing vertebrate fossils and looks forward to improving her skillset with invertebrate fossils as well. Outside of school and the Academy, she enjoy cooking and hiking with her dog.


Alexandra Buczek

Doctoral Candidate in Comparative Biology, Richard Gilder Graduate School at the American Museum of Natural History

Advised by Melanie J. Hopkins and Jocelyn A. Sessa

Alexandra is a geologist and paleobiologist primarily interested in the influence of climate change on nearshore marine ecosystems. Alexandra’s PhD research focuses the response of Southern Californian coastal marine mollusk communities to climate change during the Plio-Pleistocene period (5.3 – 1.5 million years ago), during which the Earth experienced major warming followed by a drastic cooling into the Pleistocene glacial periods. Her multidisciplinary research brings together isotope stratigraphy, paleoecological statistical analyses, and stable isotopic data in order to determine the main changes in mollusk communities during a period of major climate change as well as deduce the environmental drivers behind those observed changes. 

For more details about her work, please don't hesitate to contact Alexandra through email.

 bryce at grand canyon

Bryce Koester

Graduate Student, Department of Biodiversity, Earth & Environmental Science

Bryce is a first year graduate student at Drexel University with a background in paleontology. Her research interests are centered around marine invertebrates, such as mollusks and foraminifera, and their responses to anthropogenic stressors. During her time as an undergraduate, Bryce researched the effects of heavy metal pollution on the mutation frequencies of foraminifera. At the Academy, Bryce will investigate the direct and indirect impacts of ocean acidification on modern pteropods, a critical organism in marine communities. Bryce is passionate about increasing the accessibility of environmental science to policy decision makers and the public and is looking forward to participating in outreach through the Academy of Natural Sciences of Drexel University.

 scientist at microscope

Andrew J. Fraass, PhD

Research Associate in Invertebrate Paleontology

As a micropalaeontologist and palaeoceanographer, Andy Fraass works to understand how past examples of climate change and evolution interact. He does this using a tiny group of single celled marine zooplankton called planktic foraminifera.

Fraass is currently working to understanding the role of biology in the carbonate cycle. The oceans currently absorb an outsized amount of carbon dioxide. Planktic foraminifera produce carbonate (CaCO3) shells. Those shells make up a substantial amount of the carbonate on the seafloor. This carbonate acts like a buffer, helping to stabilize the ocean’s chemistry. Those shells are also the world’s best fossil record, one good enough we can examine how species evolve, not genera or families like we usually need to use. We know that when these plankton go extinct there’s a change in the amount of carbonate deposited. Using a new database with >50 years of scientific ocean drilling data, Andy works to understand what the key risks are to plankton during several past examples of climate change and how those key risks are expressed in the deposition of carbonate.

Fraass is a Research Associate with the Academy, but he can normally be found at the University of Bristol where he is a Vice Chancellor’s Fellow in Earth Sciences.

For more more details about Andy’s work, please check out:


 a photo of chase

Chase Foster

Undergraduate Curatorial Assistant

Chase is a junior Environmental Science major with a concentration in Ecology and Evolution. Although she is an ENVS major, she is intrigued by the mysterious elements of geo. She is excited to join the IP family and learn about new and exciting parts of geology. Chase enjoys biking, gardening, and music. She is a part of Drexel’s Jazz ensemble Naturally Sharp and the University Chorus. Chase plans to work in agriculture in the future, or as a park/forest ranger.

 a photo of daouda

Daouda Njie

Undergraduate Curatorial Assistant

Daouda is a junior Environmental Science major at Drexel University with concentrations in Ecology and Evolution. He is interested in pursuing restoration ecology and studying interspecies interactions. Daouda is excited to refine his data management skills as he catalogs the academy’s invertebrate collection. In his free time, he likes creating terrariums, photography, and hiking.

 a photo of marie

Marie Gioulis

Undergraduate Curatorial Assistant

Marie is a third year History major and Religious Studies minor at Drexel University. In the future, she hopes to become involved in either education in museums or a history teacher. Her work at the Academy so far has allowed her to explore what it is like behind the scenes at a museum and has opened her up to the inextricable connections between science and history. Outside of her work with the Academy Marie enjoys reading, making earrings, and spending time outside.