Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls, various groups of dinosaurs, phytosaurs, aetosaurs, placodonts, and hupehsuchians.

What does the word Osteoderm mean?

: a bony plate in the skin (as of a crocodile)

What is Osteoderm function?

Osteoderms are dermal bone structures that support the upper layer of skin and serve as protection against the elements in a large variety of extinct and extant organisms, especially reptiles.

Is Osteoderm a bone?

Osteoderms are bones embedded within the skin and are common among reptiles and some mammals. They create the unique pattern on the backs of crocodiles, the armor body covering on armadillos, and the distinctive plates of dinosaurs like Stegosaurus and Ankylosaurus.

What is Osteoderm made of?

Osteoderms are composed of bone tissue, and are derived from a scleroblast neural crest cell population during embryonic development of the organism. The scleroblastic neural crest cell population shares some homologous characteristics associated with the dermis.

What does osteoderm mean?

Why are Tuataras not lizards?

The name “tuatara” is a Maori word meaning “peaks on back” or “spiny back.” Tuataras have no external ears as lizards do; they enjoy cooler weather, while lizards like it warm; and, unlike lizards, tuataras are nocturnal. But their most curious body part is a “third eye” on the top of the head.

Do birds have Osteoderm?

Scutes with a bony base are properly called osteoderms. Dermal scutes are also found in the feet of birds and tails of some mammals, and are believed to be the primitive form of dermal armour in reptiles.

What are alligator osteoderms?

Osteoderms are bony scutes embedded underneath the dermal layers of the skin acting as a protection of the alligator (Archosauria: Crocodylia) internal organs and tissues. ... They have properties similar to bone and thus have the necessary toughness to provide protection against predators.

Do lizards have Gastralia?

Gastralia (singular gastralium) are dermal bones found in the ventral body wall of modern crocodilians and tuatara, and many prehistoric tetrapods. ... Similar, but not homologous cartilagenous elements, are found in the ventral body walls of lizards and anurans.

Are birds archosaurs?

archosaur, (subclass Archosauria), any of various reptiles, including all crocodiles and birds and all descendants of their most recent common ancestor.

What is dermal Armour?

Many animals possess dermal armor, which acts primarily as protection against predators. ... The dermal armor in these animals is flexible and has a hierarchical structure with collagen fibers joining mineralized units (scales, tiles, or plates).

Do crocodiles have dermal scales?

In crocodiles and turtles, the dermal armor is formed from the deeper dermis rather than the epidermis and does not form the same sort of overlapping structure as snake scales. These dermal scales are more properly called scutes. ... They can also become similar to bones and form an outer bone armor.

What are crocodile scutes?

A scute or scutum is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds.

Do armadillos have osteoderms?

Among modern mammals, armadillos (Xenarthra, Cingulata) are the only group that possesses osteoderms, bony inclusions within the integument. Along the body, osteoderms are organized into five discrete assemblages: the head, pectoral, banded, pelvic, and tail shields.

Do turtles have osteoderms?

Reptilian Scales, Glands, and Skin Structures. Scales of crocodylians, turtles, and some lizards (e.g., anguids, cordylids, scincids) are underlain by bony plates, called osteoderms or osteoscutes, in the dermis. ... The outer layer of osteoderms is spongy, porous bone; the inner layer is compact, dense bone.

Is gastralia a dermal bone?

Gastralia (singular gastralium) are dermal bones found in the ventral body wall of crocodilian and Sphenodon species. They are found between the sternum and pelvis, and do not articulate with the vertebrae. In modern animals, they provide support for the abdomen and attachment sites for abdominal muscles.

Why are Underbellies white?

Pale underbellies are most often found among animals that need to worry about danger from below. ... By having darker pigment on the part of the body that receives the most light and lighter pigmentation on the part that receives less light, the animal's appearance tends to flatten out and is less conspicuous.

Did T Rex have gastralia?

The skeletal mount is one of the first to include the gastralia, bones that provided support for the abdomen on the underside of the T. rex between the sternum and the pelvis.

What is the difference between alligator and crocodile?

The most obvious way to discern the two reptiles is to stare down their sinister snouts. Alligators have U-shaped faces that are wide and short, while crocodiles have slender almost V-shaped muzzles. ... When an alligator closes its mouth, you tend to see only its upper teeth.

Do snakes have scutes?

Snakes, like other reptiles, have skin covered in scales. Snakes are entirely covered with scales or scutes of various shapes and sizes, known as snakeskin as a whole. ... The arrangement of scales is used to identify snake species.

Why do crocodiles have scutes?

The scales on a crocodiles back are thick to be able to withstand the heat of the sun. The larger scales have formed to reduce water loss through the sun exposed skin. Just like human skin, if a crocodiles stays in the sun too long, the skin will dehydrate and become uncomfortably dry.

Can humans have scales?

Ichthyosis vulgaris (ik-thee-O-sis vul-GAY-ris) is an inherited skin disorder in which dead skin cells accumulate in thick, dry scales on your skin's surface.

Do reptiles have lungs?

Unlike amphibians, reptiles breathe only through their lungs and have dry, scaly skin that prevents them from drying out. Amphibians and reptiles are together called herpetofauna, or “herps” for short.

Do lizards have hair?

Interestingly enough, just because lizards don't have fur doesn't mean they couldn't have hair. In fact, some of them do have hair, but not how you may think. Hair, fur, feathers, and scales are all made up in large part by keratin proteins.