Dichotomous Key/Sirenia

1: Shape of tail

 * Tail shape
 * Forked - Dugong dugon
 * Paddle-shaped -

2: Trichechidae

 * Fingernails
 * No nails on forelimbs - Amazonian Manatee, Trichechus inunguis
 * Nails on forelimbs -

3: Geographic Location

 * Rivers, estuaries, or coastal waters in the
 * Western Atlantic - Trichechus manatus
 * Eastern Atlantic - Trichechus senegalensis