turtle Skeleton. The skeletal remains of a turtle are generally left unaltered even though the amount of meat removed is considerably less than that of an intact aquatic animal. Although the percentage of meat removed is less, yet it can still be pretty hard to figure out if a turtle is alive or not. All we have to judge from are the skeletal remains.
The structure of the marine turtle skeleton is very different from the land turtles. The exoskeletal (upper shell) consists mainly of a solid shell with exoskeletons, interspersed with osteoderms (pieces of hardened cartilage) and other ribs. The middle layer (intricle) consists mostly of connective tissues, which are also used as a boney and moisture-absorbing material. The exoskeletons or the outer shell are made up mainly of keratin, and they may not be coated with a slippery substance known as “settle”. The interspersed ribs and sternum are made up of collagen which gives the impression of a turtle having a neck.
As mentioned above, the land turtles also have a bony chest cavity. This is divided into two parts – the breastbone and scapula bones. The interspersed chest bones and scapula bones also contain long fibrous cords. This cord helps in the movement of the turtle back in its sea turtle skeleton, as well as help determine the exact size of the body.
The turtle skeleton has many sub-species but the most commonly known subspecies are found on different shores of North America, namely the Eastern Pacific, Central Pacific, Florida Keys, West Pacific and Hawaiian Islands. The carapace of these sea turtles is covered with dense cover of scales, including those that resembles a snail shell. They also have small eyes, an ear-tufted upper lip, a short neck, and a head with two flippers and a sharp crest.
Unlike their land counterparts, sea turtles have a hard, thick shell called a carapace. Their carapaces differ in size, from a few inches to over 2 feet. Most of them have strong claws and teeth for protection, and their faces are also distinct, with prominent bumps, ridges, and crests. They also display some unique features like the presence of “torsos” or bumps on the underside of the plastron.
All the aforementioned characteristics of sea turtles are present in land-based turtles, except the fact that land-based turtles have a thicker shell covering. Land-based turtles have evolved from the ancestral species that walked on its own all over the oceans. As such, their ancestry goes back to the ancestor of dinosaurs. The evolution of turtles also includes the presence of an element called ambition, which is a type of “muscle enclosure,” which helps the sea turtle walk on its toes.
The plastron or the upper portion of a turtle shell is the area between the plastron’s edge and the anterior carapace. This area is called the “ocellar,” and it has many bones and other elements that constitute the body of a turtle. A part of the ocellar is the bony area, which is lined with osteocytes (oste cells). Bony areas are present even in the non-erect stage of life in both land and freshwater turtles. Ocellaric shells are found in both sexes of all turtle species, while bony carcases are only found in females.
Tortoises are closely related to sea turtles, but they are smaller than sea turtles. A well-developed tortoise’s skeleton has two different sections: the plastron and the anterior carapace. The former acts as the plastron of the animal, while the latter is the main part of a tortoise’s bone and skeleton. These differences help explain why the two animals have distinct shell shapes, with the former having a more flattened shell shape, while the latter has a longer, slimmer shell shape.