The patagium (pl.: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flying. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosaurs, pterosaurs, gliding mammals, some flying lizards, and flying frogs. The patagium that stretches between an animal's hind limbs is called the uropatagium (especially in bats) or the interfemoral membrane.
In bats, the skin forming the surface of the wing is an extension of the skin of the abdomen that runs to the tip of each digit, uniting the forelimb with the body.
The patagium of a bat has four distinct parts:
In the flying pterosaurs, the patagium was composed of the membrane forming the surface of the wing, supported primarily between the body and the elongated fourth finger.
The patagium of a pterosaur had three distinct parts: [1]
Flying squirrels, sugar gliders, colugos, anomalures and other mammals also have patagia that extend between the limbs; as in bats and pterosaurs, they also possess propatagia and uropatagia. Though the forelimb is not as specialised as in true flyers, the membrane tends to be an equally complex organ, composed of various muscle groups and fibers. [3] [4] Various species have styliform bones to support the membranes, either on the elbow (colugos, anomalures, greater glider, Eomys ) or on the wrist (flying squirrels).
In gliding species, such as some lizards and flying frogs, the patagium is the flat parachute-like extension of skin that catches the air, which allows gliding flight.[ citation needed ]
In birds, the propatagium is the elastic fold of skin extending from the shoulder to the carpal joint, making up the leading edge of the inner wing. Many authors use the term to describe the fold of skin between the body (behind the shoulder) and the elbow that houses the outer segments of the latissimus dorsi caudalis and triceps scapularis muscles. [5] Similarly the fleshy pad that houses the follicles of the remiges (primary and secondary feathers) caudal to the hand and the ulna is also often referred to as a patagium. [6] The interremigial ligament that connects the bases all the primary and secondary feathers as it passes from the tip of the hand to the elbow is thought to represent the caudal edge of the ancestral form of this patagium.
The scansoriopterygid dinosaurs Yi and Ambopteryx had rather elaborate, superficially bat-like patagia in the forelimbs, unique among dinosaurs. The exact extent is not clear, but they were extensive and supported by a long styliform bone as in gliding mammals. Other scansoriopterygids might have had similar patagia, based on their long third fingers.[ citation needed ]
Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous. Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger.
Colugos are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur and the Philippine flying lemur. These two species make up the entire family Cynocephalidae and order Dermoptera.
Draco is a genus of agamid lizards that are also known as flying lizards, flying dragons or gliding lizards. These lizards are capable of gliding flight via membranes that may be extended to create wings (patagia), formed by an enlarged set of ribs. They are arboreal insectivores.
Flying squirrels are a tribe of 50 species of squirrels in the family Sciuridae. Despite their name, they are not in fact capable of full flight in the same way as birds or bats, but they are able to glide from one tree to another with the aid of a patagium, a furred skin membrane that stretches from wrist to ankle. Their long tails also provide stability as they glide. Anatomically they are very similar to other squirrels with a number of adaptations to suit their lifestyle; their limb bones are longer and their hand bones, foot bones, and distal vertebrae are shorter. Flying squirrels are able to steer and exert control over their glide path with their limbs and tail.
The Anomaluridae are a family of rodents found in central Africa. They are known as anomalures or scaly-tailed squirrels. The six extant species are classified into two genera.
A forelimb or front limb is one of the paired articulated appendages (limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead. In bipedal animals with an upright posture, the term upper limb is often used.
Scansoriopterygidae is an extinct family of climbing and gliding maniraptoran dinosaurs. Scansoriopterygids are known from five well-preserved fossils, representing four species, unearthed in the Tiaojishan Formation fossil beds of Liaoning and Hebei, China.
A number of animals are capable of aerial locomotion, either by powered flight or by gliding. This trait has appeared by evolution many times, without any single common ancestor. Flight has evolved at least four times in separate animals: insects, pterosaurs, birds, and bats. Gliding has evolved on many more occasions. Usually the development is to aid canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among rainforest animals, especially in the rainforests in Asia where the trees are tall and widely spaced. Several species of aquatic animals, and a few amphibians and reptiles have also evolved this gliding flight ability, typically as a means of evading predators.
Sharovipteryx is a genus of early gliding reptiles containing the single species Sharovipteryx mirabilis. It is known from a single fossil and is the only glider with a membrane surrounding the pelvis instead of the pectoral girdle. This lizard-like reptile was found in 1965 in the Madygen Formation, Dzailauchou, on the southwest edge of the Fergana Valley in Kyrgyzstan, in what was then the Asian part of the U.S.S.R. dating to the middle-late Triassic period. The Madygen horizon displays flora that put it in the Upper Triassic. An unusual reptile, Longisquama, was also found there.
The Philippine flying lemur or Philippine colugo, known locally as kagwang, is one of two species of colugo or "flying lemurs". It is monotypic of its genus. Although it is called "flying lemur", the Philippine flying lemur is neither a lemur nor does it fly. Instead, it glides as it leaps among trees.
Around 350 BCE, Aristotle and other philosophers of the time attempted to explain the aerodynamics of avian flight. Even after the discovery of the ancestral bird Archaeopteryx which lived over 150 million years ago, debates still persist regarding the evolution of flight. There are three leading hypotheses pertaining to avian flight: Pouncing Proavis model, Cursorial model, and Arboreal model.
Gliding flight is heavier-than-air flight without the use of thrust; the term volplaning also refers to this mode of flight in animals. It is employed by gliding animals and by aircraft such as gliders. This mode of flight involves flying a significant distance horizontally compared to its descent and therefore can be distinguished from a mostly straight downward descent like a round parachute.
Pel's flying squirrel or Pel's scaly-tailed squirrel is a species of rodent in the family Anomaluridae. It is found in Liberia, Ivory Coast, and Ghana, where it lives in lowland tropical rainforests. It is named after Hendrik Pel.
The red and white giant flying squirrel is a species of rodent in the family Sciuridae. It is a very large, dark rufous-red, buff and white flying squirrel found in forests at altitudes of 800–3,500 m (2,600–11,500 ft) in mainland China and 1,200–3,750 m (3,940–12,300 ft) in Taiwan, although the population of the latter island is distinctive and likely better regarded as a separate species, the Taiwan giant flying squirrel. Additionally, the red and white giant flying squirrel possibly ranges into northeastern South Asia and far northern Mainland Southeast Asia. This squirrel has a wide range and is relatively common, and the International Union for Conservation of Nature lists it as being of "least concern".
The Cameroon scaly-tail, also referred to as the Cameroon anomalure, flightless anomalure or flightless scaly-tail, is a rodent species endemic to West Central Africa. The scientific literature has never reported observations of live individuals. The taxonomic classification of the species has been subject to recent revision.
Proavis refers to a hypothetical extinct species or hypothetical extinct taxon and was coined in the early 20th century in an attempt to support and explain the hypothetical evolutionary steps and anatomical adaptations leading from non-avian theropod dinosaurs to birds. The term has also been used by defenders of the thecodontian origin of birds.
Role of skin in locomotion describes how the integumentary system is involved in locomotion. Typically the integumentary system can be thought of as skin, however the integumentary system also includes the segmented exoskeleton in arthropods and feathers of birds. The primary role of the integumentary system is to provide protection for the body. However, the structure of the skin has evolved to aid animals in their different modes of locomotion. Soft bodied animals such as starfish rely on the arrangement of the fibers in their tube feet for movement. Eels, snakes, and fish use their skin like an external tendon to generate the propulsive forces need for undulatory locomotion. Vertebrates that fly, glide, and parachute also have a characteristic fiber arrangements of their flight membranes that allows for the skin to maintain its structural integrity during the stress and strain experienced during flight.
Yi is a genus of scansoriopterygid dinosaurs from the Late Jurassic of China. Its only species, Yi qi, is known from a single fossil specimen of an adult individual found in Middle or Late Jurassic Tiaojishan Formation of Hebei, China, approximately 159 million years ago. It was a small, possibly tree-dwelling (arboreal) animal. Like other scansoriopterygids, Yi possessed an unusual, elongated third finger, that appears to have helped to support a membranous gliding plane made of skin. The planes of Yi qi were also supported by a long, bony strut attached to the wrist. This modified wrist bone and membrane-based plane is unique among all known dinosaurs, and might have resulted in wings similar in appearance to those of bats.
Bats are the only mammal capable of true flight. Bats use flight for capturing prey, breeding, avoiding predators, and long-distance migration. Bat wing morphology is often highly specialized to the needs of the species.
Ambopteryx is a genus of scansoriopterygid dinosaur from the Oxfordian stage of the Late Jurassic of China. It is the second dinosaur to be found with both feathers and bat-like membranous wings. Yi, the first such dinosaur, was described in 2015 and is the sister taxon to Ambopteryx. The holotype specimen is thought to be a sub-adult or adult. The specimen is estimated to have had a body length of 32 centimetres (13 in) and a weight of 306 grams (0.675 lb). The genus includes one species, Ambopteryx longibrachium.