This lifeform is found widely in the Atlantic Ocean. This lifeform is found widely in the Pacific Ocean.
Green Turtle (Chelonia mydas) is found in all tropical oceans of the world. This species can become quite large with a carapace (top shell) of up to 1.5 meters in length. Those examples from the eastern Pacific (near Mexico, etc.) should be called Chelonia mydas agassizii or possibly even Chelonia agassizii.
Sea Turtles (Family Chelonidae) are marine animals that come to shore only to lay their eggs. Many kinds reach tremendous sizes. Because of their need for certain types of sand beaches, their edible eggs, and predictable breeding patterns, many species of this group have a threatened future.
Turtle and Tortoise group (Order Chelonia) are among the most primitive reptiles. They are egg-laying creatures characterized by having four legs, a tail, and two shells each made up of many scales that are joined together. There are about two hundred and fifty species of turtles in the world. Carl Ernst and Roger Barbour published a book entitled "Turtles of the World" by the Smithsonian Press in l989. This work covers all of the known species. The authors note that there are two hundred and fifty-seven species of living turtles. Many of these species are pictured and discussed here.
The following overview of the various families included in the Turtle Order is based on the aforementioned publication:
SCIENTIFIC NAME COMMON NAME NUMBER OF SPECIES
Pelomedusidae Side Necked 23 species
Chelidae Side Necked 36 species
Kinosternidae Mud and Musk 22 species
Dermatemydidae River Turtle 1 species
Carettochelyidae Pig Nose 1 species
Trionychidae Soft Shelled 22 species
Dermochelyidae Leatherback 1 species
Cheloniidae Sea Turtles 6 species
Chelydridae Snapping turtles 2 species
Platysternidae Big Headed 1
Emydidae Pond and Box 91 species
Testudinidae Tortoises 50 species
256 total species
While the above counts are currently reliable, they will be impacted by findings as research continues. For example, the exact count of the species of tortoises in the Galapagos and placement of the Florida Snapping Turtle might change these counts.
Reptiles (Class Reptilia) are an ancient group of scaled chordates. These scales may be permanently joined, as in the turtles, or flexible, as in the snakes. Reptiles are land-based. Their eggs are laid on land and the young are air breathing.
Backboned Animals (Phylum Chordata) are the most advanced group of animals on earth. These animals are characterized by having a spinal cord or backbone. Most members have a clearly defined brain that controls the organism through a spinal cord. Fish, amphibians, reptiles, birds, and mammals are in this phylum.
Currently, some taxonomists believe that the fish should be divided into two groups (sharks and regular fishes) and that there are some other primitive groups in the phylum such as hagfish or lampreys.
Animal Kingdom contains numerous organisms that feed on other animals or plants. Included in the animal kingdom are the lower marine invertebrates such as sponges and corals, the jointed legged animals such as insects and spiders, and the backboned animals such as fish, amphibians, reptiles, birds, and mammals.