Vertebrates develop embryonic kidneys before the final adult kidney. Particularly for organisms with aquatic larvae such as frogs, the first embryonic kidney, the pronephros is essential for the larvae\u27s survival. Those larvae with defective or without pronephroi exhibited pronounced edema. Edema is severe swelling of a body part as a result of fluid retention. To date, although the embryonic kidneys have been extensively studied in various model organisms, it has not been studied in Eleutherodactylus coqui. E. coqui is a direct developing frog and lacks a tadpole phase in its life cycle. I examined the kidney development in E. coqui using endogenous alkaline phosphatase staining and histology. From the histology, I found that E. coqui embryos develop a pronephros followed by the mesonephros in normal development. The endogenous alkaline phosphatase staining was a novel finding and a good marker for early pronephric development in E. coqui. The kidney development in E. coqui embryos exhibiting edema was also studied. The key characteristic in the edematous embryos was the large lumens of the tubules. The edematous embryos also had poor limb development. I speculate that the edema in the E. coqui embryos was due to a defective pronephros, however, it is a correlation in the scope of this study and other causal possibilities are considered such as defects in the lymphatic system, the circulatory system and the skin. The possible relations between limb and kidney development is also discussed
