Epizoic Organisms Found On Two Captive Snapping Turtles

Epizoic organisms are often found living on animals and the relationship between the two can be mutualistic. The epizoic organisms living on turtle shells may help provide camouflage for both the alligator snapping turtle (Macrochelys temminckii) and the common snapping turtle (Chelydra serpentine). Alligator snapping turtles, which rarely leave the water except to lay eggs, are designated as endangered in Illinois. While the common snapping turtle is more abundant, the habitats of both types of snapping turtles are declining due to development and water pollution. Little is known about the biodiversity of the epizoic microorganisms that can be found on the turtle shells. Understanding this microscopic community may give information about the health of the turtle and its environment, as many of these microorganisms could serve as biological indictors of water quality. Thus, we evaluated and compared the species of microscopic epizoic organisms found on two captive snapping turtles collected in Illinois. In addition, we also compared the microorganisms found on the shells to what was found in their tanks to determine if a taxon only grew on the turtles. The epizoic microorganisms were collected from a juvenile common snapping turtle with little visible algal growth, an adult alligator snapping turtle with long tufts of macro-algal growth, and from rocks and logs within their tanks. Microorganisms that were found on both types of turtles were rotifers, testate amoebae, and Tabellaria diatoms. On the alligator snapping turtle the macro-alga Basicladia was abundant and there were also Vampyrella amoebas and Vortcilla ciliates present. There was also an unidentified microorganism and a nematode found on the common snapping turtle shell. The only microorganisms found growing on both the alligator snapping turtle and its tank were Vortcilla ciliates. No microorganisms were found on both on the common snapping turtle and its tank. The occurrence of several taxa of microorganisms on turtle shells but not elsewhere in the tanks suggests that they may be true epizoic organisms that prefer to grow on animals rather than on inert surfaces. Further research should examine the potential mutualistic benefits that both turtles and epizoic microorganisms receive from this relationship