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Scorpions, scaly pearl oysters, and a new species

By Amy Lohmann '14
July 28, 2011

Hal Halvorson '11 in the Regents Hall lab where he has conducted much of his research.

Hal Halvorson '11 was busy collecting critters as part of this year's Island Biology in the Bahamas course when he flipped over a rock and found himself face-to-face with what appeared to be an unusual-looking scorpion.

Upon returning to the lab, Halvorson realized the specimen he found had never before been seen in the Bahamas. To add to his find, he noticed a species of pseudoscorpion laying in the petri dish next to his first discovery — and that, too, turned out to be an unprecedented species in the Bahamas.

Halvorson had stumbled upon two possible new species of arachnids in the same day.

This summer Halvorson presented his findings at the 14th Natural History of the Bahamas Symposium. He had heard about the conference from Professor of Biology Eric Cole, who teaches the Island Biology in the Bahamas course and oversees an independent research course examining scaly pearl oysters that Halvorson took this spring.

Halvorson's presentation at the conference touched on both his work on scaly pearl oysters and his scorpion findings. "We had a collection of biologists and archaeologists present, and the symposium was organized so as to mix up the disciplines," says Halvorson. "The opportunity to interact with other undergraduate and graduate students doing research in the Bahamas was very rewarding."

Although the discovery of two potential new species received a great deal of attention (more labwork is needed to confirm that they are a new species), Halvorson's primary area of research on the Interim course Island Biology in the Bahamas was examining the sex determination of scaly pearl oysters, a realm of study that he has been devoted to for the past academic year.

Halvorson began his research on scaly pearl oysters last summer when he and Kosaizee Yang '11 teamed up with Cole. That research experience prompted Halvorson to enlist in Cole's 2011 Interim course in the Bahamas. The students spent the month of January on San Salvador Island, one of the outer islands of the Bahamas, familiarizing themselves with the local biology.

One of the two new species of arachnids that Hal Halvorson '11 discovered during the Island Biology in the Bahamas course this winter.

"We were able to design our own projects investigating one or two questions about the biology of San Salvador that we were interested in answering," says Halvorson. "Professor Cole let us loose on the island, and we all spent our time setting up different experiments and gathering data to answer our question or address some sort of hypothesis."

Halvorson worked with other students to identify the gender of oysters in the field, placing the oysters in cages and then setting them back in their ponds for further examination upon returning in June. It was during this project that Halvorson made his discovery of the scorpion and pseudoscorpion.

"This summer I have been working with Professor Cole again," says Halvorson. "Now we have determined that a number of oysters we placed in cages in one of the ponds on San Salvador have switched back from being female to male, meaning that oysters in this population can undergo sex reversal. This finding was probably the most important of the whole trip and has a lot of implications for the future of the project."

Halvorson will be publishing a paper on his findings on scaly pearl oysters and will be starting graduate studies in Arkansas this fall.

Contact Kari VanDerVeen at 507-786-3970 or