Dermoptera

The dermoptera (Dermoptera), also known as colugos, are an order of placental mammals with only two extant species belonging to to the only family in the order, Cynocephalidae.

Although sometimes called "flying lemurs," Dermoptera are not primates. Recent studies of the DNA of these animals carried out at the University of Texas, USA, have revealed that primates and dermopterans had a common ancestor about 80 million years ago, during the Cretaceous.

They are arboreal animals that have a skin membrane or patagium that joins the extremities with the body. They eat fruits and leaves.

Features

Colugos are nocturnal mammals that live in trees.

Appearance and Anatomy

They reach a length of 35–40 cm (14–16 in) and weigh 1–2 kg (2.2–4.4 lb). They have long, slender forelimbs and a medium-length tail. and a relatively light build. The head is small, with large, forward-focused eyes for excellent binocular vision, and small, rounded ears.

The incisor teeth of colugos are very characteristic; They are comb-shaped with up to 20 teeth on each tooth. The incisors are analogous in appearance and function to the incisor set of strepsirrhines, which is used for grooming. The upper second incisors have two roots, another feature unique among mammals. The dental formula for colugos is: 2.1.2.3 3.1.2.3

Feet of the Filipino collugo.

Movement

Colugos are good gliders, and can move up to 70 m (230 ft) from tree to tree without losing much altitude, with one Malayan colugo (Galeopterus variegatus) recorded to have traveled about 150 m (490 ft).) on a glide.

Of all gliding mammals, colugos have the most sophisticated adaptations for flight. They have a large membrane of skin that stretches between their paired limbs and gives them the ability to glide significant distances between trees. This membrane, or patagium, extends from the shoulder blades to the front feet, from the tips of the hind fingers to the tips of the toes, and from the hind feet to the tip of the tail. that colugos were close relatives of bats. Today, due to genetic data, they are considered more closely related to primates.

Lower jaw of a Galeopterus

Colugos are inexperienced climbers; they lack opposable thumbs. They climb trees in slow hops, clinging to the bark with their small, sharp claws. They spend most of the day resting. At night, colugos spend most of their time in trees foraging for food, gliding to find another tree, or to find potential mates and protect their territory.

Behavior and Diet

Colugos are shy, nocturnal, and solitary animals that live in the tropical forests of Southeast Asia. Therefore, very little is known about their behavior. They are herbivorous and feed on leaves, shoots, flowers, sap, and fruit. They have well-developed stomachs and long intestines capable of extracting nutrients from leaves and other fibrous materials.

Colugos have evolved to become a nocturnal species, along with the ability to see adeptly at night.

Life Cycle

Although they are placental mammals, colugos breed in a similar way to marsupials. Newborn colugos are underdeveloped and only weigh 35 g. They spend the first six months of life attached to their mother's womb. The mother coils her tail and folds the patagio into a warm, secure quasi-pouch to protect and transport her young. The hatchlings do not reach maturity until they are two to three years of age. In captivity they live up to 15 years, but their lifespan in the wild is unknown.

Status in terms of conservation status

Both species are threatened by habitat destruction, and the Philippine flying lemur was once classified by the IUCN as vulnerable. In 1996, the IUCN declared the species vulnerable due to destruction of lowland forests and hunting. ^{[citation needed]} In 2008 it was downgraded to Least Concern ^{[citation required]}, but continues to suffer the same threats. In addition to the continued clearing of its rainforest habitat, it is hunted for its meat and skin. It is also one of the favorite prey of the severely threatened Philippine eagle (Pithecophaga jefferyi); some studies suggest that colugos make up 90% of the eagle's diet ^{[citation needed]}

Taxonomy

Drawing from a collugo.

Dermoptera have an abundant fossil record from the late Paleocene, evidence of a flourishing past, but only two species of the family Cynocephalidae survive today:

• Cyriacotheriidae†

Gender Cyriacotherium† (sometimes considered a skeleton).

Gender Thylacaelurus†

• Plagiomenidae family†

Genero Eudaemonema†

Genero Elpidophorus†

Gender Planetetherium†

Gender Worland†

Gender Ellesmene†

Gender Plagiomene†

Gender Ekgmowechashala† (often treated as an Omomyidae primate).

Gender Tarkadectes†

Gender Tarka†

• Family Mixodectidae†

Gender Dracontolestes†

Gender Mixed†

• Cynocephalidae

Gender Dermotherium†

Gender Cynocephalus

Cynocephalus volans - Philippines

Gender Galeopterus

Galeopterus variegatus - Southeast Asia and Indonesia.

Phylogeny

The phylogeny of the dermoptera with other euarchontoglires is shown below. It should be noted that the current group phylogenetically closest to primates are the dermoptera, which is such that some authors have tried to include them as a suborder of primates, but genetic studies indicate that the differences are greater enough to consider them separate orders.