Investigating the Unknown: A Study of Freshwater Stingray Anatomy and an Evaluation of the Effectiveness of Routine Diagnostic Imaging Techniques

Date of Award


Degree Type


Degree Name

Master of Science in Biomedical Sciences

First Advisor

Brian Matayoshi, PhD

Second Advisor

H Keith Brown, PhD

Third Advisor

Mary Owen, PhD, JD

Fourth Advisor

Bonnie Buxton, PhD


The goal of this Master's thesis project was to develop and create a complete and comprehensive atlas of freshwater stingray anatomy by compiling information gathered through dissection, ultrasound, x-ray, MRI and CT scans. A complete and detailed atlas of stingray anatomy has not yet been developed and is an essential first step and valuable tool in the study of stingray speciation and physiology. Ultrasound, x-ray, CT and MRI were conducted on both male and female Potamottygon motoro, freshwater stingrays. Both the male and female P. motoro stingrays were then completely dissected to compare the actual anatomy seen in dissection to the anatomy seen in the images. The images from both dissection and imaging were then compiled and labeled for comparison. The thoracic and abdominal cavities were dissected completely, as well as the components of the urogenital tract and the neurocranium. The anatomical structures seen during dissection of both the male and female stingrays were unremarkable for the most part and resembled the descriptions described from previous research. However, several interesting findings were noted. Foreign objects were visible on the images obtained from both the male and female stingray, but were not revealed in during dissection. Relevant findings during dissection included the presence of an interrenal gland, anatomical components of the vestibular system, presence of a lateral line system, presence of an asymmetric cerebellum in both the male and female specimens, and noted absence of a pre-pelvic process in both male specimens. Following analysis of imaging and dissection findings, the imaging techniques were assessed individually for their contribution and value in imaging stingrays. The necessity for understanding which type of imaging best showed which anatomical structures was most cost-efficient and easily accessible is of value to aquarists and hobbyists who care for these expensive animals.

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