The Water Penny is typically 0.1 inches to 0.2 inches (4mm to 6mm) in size and has the following descriptors / identifiers: round; shell; stuck; horseshoe crab-like; underwater; fossil; trilobite; brown; black.
It has a typical diet of the following: algae; detritus.
Territorial Area Map (Visual Reference Guide)
The map below showcases (in blue) the states and territories of North America where the Water Penny may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.