The Varanidae are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

s in the superfamily Varanoidea and order Anguimorpha. The family, a group of

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

and frugivorous lizards, includes the living

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

'' Varanus'' and a number of extinct genera more closely related to ''Varanus'' than to the earless monitor lizard (''Lanthanotus''). ''Varanus'' includes the

Komodo dragon The Komodo dragon (''Varanus komodoensis''), also known as the Komodo monitor, is a large reptile of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo (island), Komodo, Rinca, Flores, Gili Dasami, and Gili ...

(the largest living lizard), crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the earless monitor lizard and Chinese crocodile lizard. The oldest members of the family are known from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

of Mongolia.

Taxonomy

The Varanidae were defined (using morphological characteristics) by Estes, de Queiroz and Gauthier (1988) as the clade containing the most recent common ancestor of '' Lanthanotus'' and ''Varanus'' and all of its descendants. A similar definition was formulated by Conrad ''et al.'' (2008) (also using morphological data), who defined the Varanidae as the clade containing '' Varanus varius'', '' Lanthanotus borneensis'', and all descendants of their last common ancestor. Using one of these definitions leads to the inclusion of the earless monitor lizard (''L. borneensis'') in the family Varanidae. Lee (1997) created a different definition of the Varanidae, defining them as the clade containing ''Varanus'' and all taxa more closely related to ''Varanus'' than to ''Lanthanotus''; this definition explicitly excludes the earless monitor lizard from the Varanidae. Whether ''L. borneensis'' is included in or excluded from the Varanidae depends on the author; for example, Vidal ''et al.'' (2012) classify the earless monitor lizard as a member of a separate family Lanthanotidae, while Gauthier ''et al.'' (2012) classify it as a member of Varanidae.

Genera

:Genera marked with are

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

Genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

included in Varanidae according to Dong ''et al.'', 2022 *'' Ovoo'' Norell, Gao, & Conrad, 2008 (Mongolia, Late Cretaceous) *'' Aiolosaurus'' Gao and Norell, 2000 (Mongolia, Late Cretaceous) *'' Cherminotus'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *'' Saniwides'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *'' Paravaranus'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *'' Proplatynotia'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *'' Telmasaurus'' Gilmore, 1943 (Mongolia, Late Cretaceous) *'' Saniwa'' Leidy, 1870 (Europe, North America,

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

) *'' Archaeovaranus'' Dong ''et al.'', 2022 (China, Eocene) *'' Varanus'' Shaw, 1790

Phylogeny

Below is a

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

from Dong et al. 2022.

Biology

Monitor lizards are reputed to be among the most intelligent lizards. Most species

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...

widely and have large home ranges, and many have high stamina. Although most species are carnivorous, three

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

species in the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

('' Varanus olivaceus'', '' Varanus mabitang'', and '' Varanus bitatawa'') are primarily frugivores. Among species of living varanids, the limbs show positive allometry, being larger in larger-bodied species, although the feet become smaller as compared with the lengths of the other limb segments. Varanids possess unidirectional pulmonary airflow, including air-sacs akin to those of birds.Unidirectional Airflow In The Lungs Of Birds, Crocs And Now Monitor Lizards
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References

External links