2005 Student Research Conference:
18th Annual Student Research Conference


Using Electron Microscopy to Study the Minute Male Parts of Freshwater Physid Snails
Sarah E. Starnes*, Diana L. Brunsman, Jacob Akins, Ashley Burden♦, Ryan N. Douglas, John Eddy, Erin O'Neal, Benjamin A. Schmidt, and Christopher Spencer
Dr. George L. Shinn, Faculty Mentor

Freshwater snails are traditionally identified by distinctive aspects of shell shape, but modern studies reveal that shell features can be variable even within species and that some species are more dependably differentiated by gross anatomical features of the male system. We have used light microscopy and scanning electron microscopy to compare the male reproductive systems of two species of Physa that are common in NE Missouri. In snails tentatively identified as Physa acuta, the penis is surrounded by a thin-walled “membranous” penis sheath. In the second species, Physa gyrina, the penis sheath has two parts, including a thin-walled membranous region and a thick-walled glandular region. Secretions of the glandular region accumulate in the lumen of the penis sheath. Both species are hermaphroditic; in addition to the protrusible penis their male systems include an eversible prepution that deposits sperm into the mantle cavity of mates.

Keywords: Physa, snails, reproduction, electron microscopy


Presentation Type: Poster

Session: 29-59
Location: OP Lobby & Atrium
Time: 1:15

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* Indicates the Student Presenter
♦ Indicates Truman Graduate Student
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