| Varanus (Polydaedalus) | |
|---|---|
 | |
| Nile monitor in South Africa | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Family: | Varanidae |
| Genus: | Varanus |
| Subgenus: | Polydaedalus |
| Species | |
Polydaedalus, commonly referred as African monitors, is one of the 11 subgenera of the genus Varanus . [1] Its species are native to Africa and West Asia, among which are Africa's largest lizards.
African monitors are typically medium-sized monitor lizards, with males being larger than females. They are characterized by their tall heads and nostrils positioned close to their eyes. Their jaws are short and equipped with round, thick teeth. They have long necks and muscular tails, like all monitors do. [2]
African monitors produced the two largest species of monitors in Africa. Nile monitors usually measure 1 m (3 ft 3 in) in length and weighs around 5 kg (11 lb), with exceptionally large specimens exceeding 2.4 m (7 ft 10 in) in length and 20 kg (44 lb) in mass, making it not only the fourth largest lizard after the Komodo dragon, Asian water monitor and crocodile monitor, but also the second largest reptile in the Nile Basin after its crocodile counterpart. The rock monitor is much bulkier and is larger on average, but has a slightly smaller maximum size of just more than 2 m (6 ft 7 in) long but still weighing over 15 kg (33 lb), rivalling the perentie as the world's fifth largest lizard. [3]
The genus Varanus is believed to have originated in South Asia, and the anatomy of its earliest members are thought to resemble modern members of Empagusia , such as the Bengal monitor. Other monitors spread across the Old World in two directions: true monitors (subgenus Varanus ), tree monitors (subgenus Hapturosaurus ) and dwarf monitors (subgenus Odatria ) moved east towards Southeast Asia and Oceania, quickly diversifying into different niches. Meanwhile, desert monitors (subgenus Psammosaurus ) and African monitors (subgenus Polydaedalus) moved west towards Central Asia, the Middle East and Africa, developing a corporal built that is suited for a diet in a dry region: tall skulls and round teeth can crush shells of invertebrates easily, and caudally positioned nostrils can help them avoid breathing sand particles in the air while travelling through dry and dusty areas, such as deserts. Despite so, the Nile monitor, living in the Nile Basin with a rich resource of freshwater, has adapted a piscivorous diet, feeding mostly on fish. The rock monitor, being large and able to swallow large prey, often seek chances to eat turtles, which contributes most of its vertebrate food. [4]
African monitors thrive throughout the African continent. Nile monitors are the most populous lizards in Africa, with over 4 million widely distributed across Sub-Sahara in all habitats but deserts. Rock monitors are also abundant, having 4 subspecies and a combined population in the millions.
The Komodo dragon, also known as the Komodo monitor, is a member of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, and Gili Motang. It is the largest extant species of lizard, growing to a maximum length of 3 m (9.8 ft), and weighing up to 70 kg (150 lb).
Monitor lizards are lizards in the genus Varanus, the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recognized.
Megalania is an extinct species of giant monitor lizard, part of the megafaunal assemblage that inhabited Australia during the Pleistocene. It is the largest terrestrial lizard known to have existed, reaching an estimated length of 3.5 to 7 metres, and weighing between 97–1,940 kg (214–4,277 lb), but the fragmentary nature of known remains make estimates highly uncertain.
The saltwater crocodile is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been listed as Least Concern on the IUCN Red List since 1996. It was hunted for its skin throughout its range up to the 1970s, and is threatened by illegal killing and habitat loss. It is regarded as dangerous to humans.
The term Australian megafauna refers to the megafauna in Australia during the Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, and the roles of human and climatic factors in their extinction are contested.
The Nile crocodile is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed in sub-Saharan Africa, occurring mostly in the eastern, southern, and central regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps, and marshlands. Although capable of living in saline environments, this species is rarely found in saltwater, but occasionally inhabits deltas and brackish lakes. The range of this species once stretched northward throughout the Nile River, as far north as the Nile Delta. Lake Rudolf in Kenya has one of the largest undisturbed populations of Nile crocodiles. Generally, the adult male Nile crocodile is between 3.5 and 5 m in length and weighs 225 to 750 kg. However, specimens exceeding 6.1 m (20 ft) in length and 1,000 kg (2,200 lb) in weight have been recorded. It is the largest freshwater predator in Africa, and may be considered the second-largest extant reptile in the world, after the saltwater crocodile. Size is sexually dimorphic, with females usually about 30% smaller than males. The crocodile has thick, scaly, heavily armoured skin.
The Nile monitor is a large member of the monitor family (Varanidae) found throughout most of Sub-Saharan Africa, particularly in drier regions, and along the Nile River and its tributaries in East Africa. Additionally, there are modern, invasive populations in North America. The population found in West African forests and savannahs is sometimes recognized as a separate species, the West African Nile monitor. While it is dwarfed by its larger relatives, such as the Komodo dragon, the Asian water monitor or the crocodile monitor, it is still one of the largest lizards in the world, reaching Australia’s perentie in size. Other common names include the African small-grain lizard, as well as iguana and various forms derived from it, such as guana, water leguaan or river leguaan.
The perentie is a species of monitor lizard. It is one of the largest living lizards on earth, after the Komodo dragon, Asian water monitor, and the Crocodile monitor. Found west of the Great Dividing Range in the arid areas of Australia, it is rarely seen, because of its shyness and the remoteness of much of its range from human habitation. The species is considered to be a least-concern species according to the International Union for Conservation of Nature.
The Asian water monitor is a large varanid lizard native to South and Southeast Asia. It is widely considered to be the second-largest lizard species, after the Komodo dragon. It is distributed from eastern and northeastern India and Bangladesh, the Andaman and Nicobar Islands, Sri Lanka, through southern China and Hainan Island in the east to mainland Southeast Asia and the islands of Sumatra, Borneo, Java, Lombok, the Riau Archipelago, Sulawesi. It is one of the most widespread monitor lizards.
The crocodile monitor, also known as the Papuan monitor or Salvadori's monitor, is a species of monitor lizard endemic to New Guinea. It is the largest monitor lizard in New Guinea and is one of the longest lizards, verified at up to 255 cm (100 in). Its tail is exceptionally long, with some specimens having been claimed to exceed the length of the Komodo dragon, however less massive.
Varanus timorensis, the Timor monitor or spotted tree monitor, is a species of small monitor lizards native to the island of Timor and some adjacent islands.
The dwarf crocodile, also known as the African dwarf crocodile, broad-snouted crocodile or bony crocodile, is an African crocodile that is also the smallest extant (living) species of crocodile.
The rock monitor is a species of monitor lizard in the family Varanidae. The species is endemic to Sub-Saharan Africa, where, on average it is the largest lizard found on the continent. It is called leguaan or likkewaan in some areas.
The yellow-headed water monitor, also commonly known as Cuming's water monitor, the Mindanao water monitor, and the Philippine water monitor, is a large species of monitor lizard in the family Varanidae. The species is endemic to the Philippines. It thrives in mangrove, forest and water margins in tropical refuges, where it feeds on birds, fishes, mammals, and carrion.
The Northern Sierra Madre forest monitor, also known by the local names bitatawa, baritatawa, and butikaw, is a large, arboreal, frugivorous lizard of the genus Varanus.
Odatria, commonly known as dwarf monitors, consists of small monitor lizards found in Australia and Indonesia. Species in this subgenus include the smallest monitor species in the world, the tiny 16 gram Dampier Peninsula monitor, but also includes some more medium sized species such as the 240 gram black-palmed rock monitor.
Varanus darevskii, also known as the Central Asian monitor, is an extinct species of monitor lizard from the Early Pliocene of Tajikistan, known from a partial skull. V. darevskii might have been a close relative of, and perhaps ancestral to, the modern desert monitor.
Varanus, commonly known as true monitors, is one of the 11 subgenera of the genus Varanus. All of its species are found in the Australasian realm, among which are the world's largest lizards.