In the 2012 President's Budget Request, the National Biological Information Infrastructure (NBII) is terminated. As a result, all resources, databases, tools, and applications within this web site will be removed on January 15, 2012. For more information, please refer to the NBII Program Termination page.
The OBIS-USA database brings together highly distributed marine species data sets, documenting where and when species were observed or collected, and allows them to be searched and mapped by geographic location.
Turtles are members of the taxon Testudines. The morphology of the skull and bone helps define the group. For example, turtles lack fenestrae (holes) in the skull, which contrasts with the diapsid (two-holed) skull of other reptiles and birds.
All turtles have a shell, and the head, limbs, and tail protrude from the shell's front (anterior) and back (posterior) openings. Turtles also lack teeth and lay eggs (oviparity) for reproduction. Over 300 species of turtles exist worldwide, spanning all oceans and all continents but Antarctica. The most common turtles of North America are emydids, which include pond turtles, sliders, map turtles, and painted turtles. Other types of turtles native to the continent include the snapping turtles (Chelydridae), several species of sea turtles (Cheloniidae and Dermochelyidae), and a few species of tortoises (Testudinidae).
Turtles are most often introduced by people releasing their unwanted pets. If they are a popular species in the pet trade, and are released in large enough numbers they can become established. The main species carried in the pet trade is red-eared sliders. This species has become established in a number of locations.
