A lifetime of work was spread across the tables of a basement biology lab in McCollum Science Hall.

Led by University of Northern Iowa biology professor Carl Thurman, one of the world’s top experts in fiddler crab biology, a group of four students is curating a collection of preserved crabs for the American Museum of Natural History in New York City. Researchers there will incorporate the collection into the permanent holdings of the museum. 

Hundreds of jars filled with thousands of specimens of fiddler crabs bobbed in an 80% alcohol solution behind waterproof labels, neatly arranged in rows and groups. The jars, collected over an almost 40-year span, will provide both a valuable research experience for the undergraduates and preserve a detailed snapshot of the species for future study.

The specimens were collected by Frank Barnwell, former chair of the department of ecology, evolution and behavior at the University of Minnesota. Barnwell, who was Thurman’s advisor while he was earning his doctorate, spent almost 40 years collecting the specimens from the shores of the U.S., Mexico, Costa Rica, Caribbean Islands and Brazil, as well as southern Europe, Africa, Malaysia, the Philippines, New Guinea, Fiji and Taiwan.

“Due to the time and effort put into collecting these crabs, the collection is a biological asset of immeasurable value,” Thurman said. 

Thurman’s students painstakingly sorted through more than 7,700 crab specimens - some less than an inch in size. All told, they tabulated 64 species, winnowing almost 1,000 jars down to 566, discarding dry or redundant specimens and cataloguing those that remained by count, sex, species and location collected. 

The information will be used in biogeographic studies charting the distribution and diversity of land crab species across the world that the students will publish and present as a poster at the end of July in the UNI – Summer Undergraduate Research Symposium.

When the collection is delivered to the American Museum of Natural History, it will provide future researchers with a detailed snapshot of the land crab population from 1965 to 2000, allowing them to compare the health, range and habitat of the species over time and determine the impacts of climate change and human interference on the species.

“Land crabs are bio-indicators of environmental health,” Thurman said. “Because each species is  specialized and occupies a specific niche, they indicate changes in the habitat that might not be detected by the human eye alone.”