(25) To X-ray or to Clear and Stain? That is the question. Comparing Two Techniques of Analyzing Sexual Dimorphic Mosquito Fish Skeletal Structures

     Male mosquitofish (Gambusia affinis) have sexual dimorphic skeletal characteristics that are establish during development: namely an anal fin elongated into a gonopodium and enlarged hemal spines. Enlarged hemal... [ view full abstract ]

     Male mosquitofish (Gambusia affinis) have sexual dimorphic skeletal characteristics that are establish during development: namely an anal fin elongated into a gonopodium and enlarged hemal spines. Enlarged hemal spines serve as muscles anchoring points that direct the gonopodium, during its use in copulatory sperm transfer. The classic technique to investigate these structures has been to enzymatically clear the fish tissues, stain ossified tissues with Alizarin red, and observe under a dissecting microscope. While reliable, this technique is time consuming. Here, w quantitatively compare measurements taken from cleared and stained male mosquitofish to alternative measurements taken from high-resolution x-rays of the same fish. Specifically, we examine the achievable resolution of analyzing sexually dimorphic male skeletal features and discuss the potential advantages of x-ray protocol, including more rapid sample processing.