Interfemoral membrane

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The interfemoral membrane, or uropatagium, is the membrane that stretches between the legs of bats, pterosaurs and other animals like flying squirrels and colugos.

Patagium Membranous structure that assists an animal in gliding or flight

The patagium is a membranous structure that assists an animal in gliding or flight. The structure is found in living and extinct groups of animals including bats, birds, some dromaeosaurs, pterosaurs, gliding mammals, some flying lizards, and flying frogs.

Bat Order of flying mammals

Bats are mammals of the order Chiroptera; with their forelimbs adapted as wings, they are the only mammals naturally capable of true and sustained flight. Bats are more manoeuvrable than birds, flying with their very long spread-out digits covered with a thin membrane or patagium. The smallest bat, and arguably the smallest extant mammal, is Kitti's hog-nosed bat, which is 29–34 mm (1.14–1.34 in) in length, 15 cm (5.91 in) across the wings and 2–2.6 g (0.07–0.09 oz) in mass. The largest bats are the flying foxes and the giant golden-crowned flying fox, Acerodon jubatus, which can weigh 1.6 kg (4 lb) and have a wingspan of 1.7 m.

Pterosaur Flying reptiles of the extinct clade or order Pterosauria

Pterosaurs were flying reptiles of the extinct clade or 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.

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Bats

In bats, the uropatagium extends between the legs and tail, though in tail-less/short tailed species the uropatagium either connects both legs directly (such as in phyllostomids [1] ), or is reduced to a pair of membranes along each inner side of the leg (such as in flying foxes). The uropatagium is supported by the calcar, a rod of cartilage that helps expand this membrane. The uropatagium is primarily used in flight control, allowing the bat to steer to a high degree of efficiency in the air. [2] Insectivorous species also use the uropatagium to capture insects, forming trapping pouches that hold their prey.

Calcar

The calcar, also known as the calcaneum, is the name given to a spur of cartilage arising from inner side of ankle and running along part of outer interfemoral membrane in bats. This is to help spread the interfemoral membrane, which is part of the wing membrane between the tail and the hind legs. Calcar (Femorale) also refers to the dense, vertically oriented bone present in the posteromedial region of the femoral shaft inferior to the lesser trochanter.

Unlike pterosaurs, in which the cr/uropatagium is more structurally simple than other wing membranes, bats bear fibers in their uropatagia. [3]

Pterosaurs

In pterosaurs, clear evidence of a similar membrane exists in most fossils that preserve soft tissues. However, the exact extent of this membrane in non-pterodactyloid pterosaurs isn't clear: some authorities consider that it encompassed the tail much like in most bats, while a Sordes specimen seems to indicate that it involved the hindlimbs to the exclusion of the tail. In the latter case the membrane is referred to as a cruropatagium. Unlike the other wing membranes, cr/uropatagia were fairly simple, generally lacking the specialised tissues like actinofibrils, so they're less well preserved. Meanwhile, in pterodactyloids, the membranes have clearly been reduced, and are instead an independent pair running along the inner side of each leg. [4]

Pterodactyloidea a suborder of pterosaurs (fossil)

Pterodactyloidea is one of the two traditional suborders of pterosaurs, and contains the most derived members of this group of flying reptiles. They appeared during the middle Jurassic Period, and differ from the basal rhamphorhynchoids by their short tails and long wing metacarpals. The most advanced forms also lack teeth, and by the late Cretaceous, all known pterodactyloids were toothless. Many species had well-developed crests on the skull, a form of display taken to extremes in giant-crested forms like Nyctosaurus and Tupandactylus. Pterodactyloids were the last surviving pterosaurs when the order became extinct at the end of the Cretaceous Period, together with the non-avian dinosaurs and most marine reptiles.

<i>Sordes</i> genus of reptiles (fossil)

Sordes was a small pterosaur from the late Jurassic (Oxfordian/Kimmeridgian) Karabastau Svita of Kazakhstan.

Pterosaur cr/uropatagia were supported by an elongated, opposing fifth toe, which took a similar role to that of the bat calcar. In non-pterodactyloid pterosaurs, the fifth toe is long and curved, supporting a well developed cr/uropatagium, while in pterodactyloids the fifth toe is very reduced if not outrightly lost, and the cr/uropatagia are instead reduced to a pair of membranes running along each leg. The large, unified cr/uropatagium of non-pterodactyloids seemingly offered a more stable flight, while the smaller, divided cr/uropatagia of pterodactyloids allowed a more acrobatic flight. [4]

Other animals

Several flying mammals like colugos and flying squirrels have uropatagia, usually similar to the arrangement in most bats, connecting the hindlegs to the tail.

Colugo order of mammals

Colugos are arboreal gliding mammals found in Southeast Asia, and the closest relative of the primates. Just two extant species make up the entire family Cynocephalidae and order Dermoptera. They are the most capable gliders of all gliding mammals, using flaps of extra skin between their legs to glide from higher to lower locations. They are also known as cobegos or flying lemurs, but they are not true lemurs, simply close relatives.

Flying squirrel tribe of mammals

Flying squirrels are a tribe of 50 species of squirrels in the family Sciuridae. They are not capable of flight in the same way as birds or bats but are able to glide from one tree to another with the aid of a patagium, a furry, parachute-like membrane that stretches from wrist to ankle. Their long tail provides stability in flight. Anatomically they are very similar to other squirrels but have a number of adaptations to suit their life style; their limb bones are longer and their hand, 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.

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<i>Mecistotrachelos</i> genus of reptiles

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<i>Macrotus</i> genus of mammals

Macrotus is a genus of bats in the Neotropical family Phyllostomidae. This genus contains two species, Macrotus californicus commonly known as California leaf-nosed bat and Macrotus waterhousii commonly known as Mexican or Waterhouse's leaf-nosed bat. The range of this family includes the warmer parts of the southwestern United States, Mexico, Central and South America, and the Bahama Islands. Characteristic for the genus are large ears and the name giving triangular skin flap above the nose, the "leaf". The California Leaf-nosed Bat inhabits the arid deserts of the southwestern United States as far north as Nevada, south to Baja California and Sonora, Mexico. The California Leaf-nosed Bat is of medium size, with a total length between 9 and 11 cm Its most distinctive features are the large ears, connected across the forehead. The body is pale grayish brown dorsally with whitish under parts. The pelage (fur) on the body is silky, the hairs on the back about 8 mm, on the front about 6 mm long. The posterior base of the ears are covered with hair of a woolly texture while the interior surface and most of the anterior border shows scattered long hairs. The flight membranes are thin and delicate; the wings are broad and the tail is slightly shorter that the long hind limbs and extends several millimeters beyond the uropatagium. Macrotus waterhousii is also a big eared Bat which has ranges from Sonora to Hidalgo Mexico, south to Guatemala and the Greater Antilles and Bahamas. This species roosts primarily in caves, but also in mines and buildings. This species is also insectivorous, primarily consuming insects of the order Lepidoptera and Orthoptera. The mating and parturition times of M. waterhousii vary from island to island with 4–5 months gestation.

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.

<i>Yi</i> (dinosaur) genus of reptiles (fossil)

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 160 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.

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.

References

  1. ↑ Macdonald, D., ed. (1984). The Encyclopedia of Mammals. New York: Facts on File. p. 805. ISBN   0-87196-871-1.
  2. ↑ Sharon Swartz, Aeromechanics of highly maneuverable bats, February 19th, 2014
  3. ↑ Jorn A. Cheney, Nicolai Konow, Andrew Bearnot, Sharon M. Swartz, A wrinkle in flight: the role of elastin fibres in the mechanical behaviour of bat wing membranes, Published 1 April 2015.DOI: 10.1098/rsif.2014.1286
  4. 1 2 Wilton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. ISBN   0691150613.
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