The family Emydidae is the largest family of turtles containing both freshwater and semi-terrestrial species.1 The majority of this family can be found throughout the northern hemisphere with the greatest diversity occurring in the United States and southeast Asia.1,2 Considerable variation in the morphology of white blood cells has been identified between members of the family Emydidae. This study compared blood samples from healthy representatives of the family Emydidae to determine normal cell appearance and aid in cell type identification. Samples were collected from individuals held in zoological collections around the United States. Members from 26 of the 30 genera were included in this study. An attempt was made to include at least three individuals from each representative genus. A blood sample was collected from the jugular vein, brachial or femoral venous plexus, or the dorsal coccygeal vein. Blood smears were stained with a Romanowsky stain using a Wescor 7120 Aerospray with both the medium blood and bone marrow light settings. Cell types were examined and identified under oil immersion on an Olympus BH-2 microscope. Representative cell types were documented micrographically. Erythrocyte morphology was consistent across the family. A few individuals were infected with Haemogregarina-like organisms. Heterophils and eosinophils varied in cell size, staining intensity, and granule morphology. Lymphocytes and thrombocytes were difficult to distinguish independently and thrombocytes were identified on the basis of “raft” formation. There was variability in the size of basophils. Azurophil and monocyte morphology did not vary significantly and resembled those found in other reptiles.
1. Pritchard, P.C.H. 1979. Encyclopedia of Turtles. TFH Publications, Neptune, New Jersey. 108–135.
2. Pritchard, P.C.H. 1989. Taxonomy, evolution, and zoogeography. In: Harless, M. and H. Morlock (eds.). Turtles: Perspectives and Research. Robert E. Krieger Publishing Company, Malabar, Florida. 17–26.