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 SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Varanoidea Varanoidea is a superfamily of lizards, including the well-known family Varanidae (the monitors and goannas). Also included in the Varanoidea are the Lanthanotidae ( earless monitor lizards), and the extinct Palaeovaranidae. Throughout their ...

and order

Anguimorpha The Anguimorpha is a suborder of Squamata, squamates. The group was named by Fürbringer in 1900 to include all autarchoglossans closer to ''Varanus'' and ''Anguis'' than ''Scincus''. These lizards, along with iguanians and snakes, constitute the ...

. 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 A frugivore ( ) is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance ...

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 The earless monitor lizard (''Lanthanotus borneensis'') is a semiaquatic, brown lizard native to the Southeast Asian island of Borneo. It is the only living species in the family Lanthanotidae and it is related to the true monitor lizards. Taxo ...

(''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 The crocodile monitor (''Varanus salvadorii''), also known as the Papuan monitor or Salvadori's monitor, is a species of monitor lizard Endemism, endemic to New Guinea. It is the largest monitor lizard in New Guinea and is one of the List of lar ...

savannah monitor The savannah monitor (''Varanus exanthematicus'') is a medium-sized species of monitor lizard native to Africa. The species is known as Bosc's monitor in Europe, since French scientist Louis Bosc first described the species. It belongs to the su ...

, the

goanna A goanna is any one of several species of lizard of the genus ''Monitor lizard, Varanus'' found in Australia and Southeast Asia. Around 70 species of ''Varanus'' are known, 25 of which are found in Australia. This varied group of carnivorous r ...

s of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the

and

Chinese crocodile lizard The Chinese crocodile lizard (''Shinisaurus crocodilurus'') is a semiaquatic anguimorph lizard found only in cool forests in southeastern China and northeastern Vietnam. The Chinese crocodile lizard spends much of its time in shallow water or in ...

. 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 The earless monitor lizard (''Lanthanotus borneensis'') is a semiaquatic, brown lizard native to the Southeast Asian island of Borneo. It is the monotypic, only living species in the family Lanthanotidae and it is related to the true monitor liza ...

'' 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

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 The earless monitor lizard (''Lanthanotus borneensis'') is a semiaquatic, brown lizard native to the Southeast Asian island of Borneo. It is the only living species in the family Lanthanotidae and it is related to the true monitor lizards. Taxo ...

, 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 Ovoo, oboo, or obo (, , , , Traditional Mongol: , "heap"; Chinese: 敖包 ''áobāo'', lit. "magnificent bundle .e. shrine) are cairns used as border markers or shrines in Mongolian folk religious practice and in the religion of other Mongol ...

'' Norell, Gao, & Conrad, 2008 (Mongolia, Late Cretaceous) *''

Aiolosaurus ''Aiolosaurus'' is an extinct genus of monitor lizard from the Late Cretaceous of Mongolia. The type and only species, ''Aiolosaurus oriens'', was named in 2000 from Ukhaa Tolgod, a rich fossil site in the Campanian-age Djadochta Formati ...

'' Gao and Norell, 2000 (Mongolia, Late Cretaceous) *''

Cherminotus ''Cherminotus'' is an extinct genus of varanoid lizard from the Late Cretaceous of Mongolia. The type and only species, ''Cherminotus longifrons'', was named in 1984. Description and history ''Cherminotus longifrons'' was first described ...

'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *'' Saniwides'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *'' Paravaranus'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *''

Proplatynotia ''Proplatynotia'' is an extinct genus of varanoid lizard from the Late Cretaceous of Mongolia. Fossils have been found in the Barun Goyot Formation, which is mid-Campanian in age. The type and only species, ''P. longirostrata'', was named in 19 ...

'' Borsuk-Bialynicka, 1984 (Mongolia, Late Cretaceous) *''

Telmasaurus ''Telmasaurus'' is an extinct genus of varanoid lizard from the Late Cretaceous of Mongolia. Fossils have been found from the Djadokha and Barun Goyot Formations that date between the early and middle Campanian stage from approximately 80 to 71 ...

'' Gilmore, 1943 (Mongolia, Late Cretaceous) *''

Saniwa ''Saniwa'' is an extinct genus of varanid lizard that lived during the Eocene epoch. It is known from well-preserved fossils found in the Bridger and Green River Formations of Wyoming, United States. The type species ''S. ensidens'' was describe ...

'' 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 ''Archaeovaranus'' (meaning "ancient '' Varanus''") is genus of varanid lizard from the early Eocene (Ypresian) Yuhuangding Formation of Hubei Province, China. The genus contains a single species, ''Archaeovaranus lii'', known from a nearly comp ...

'' 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 The Panay monitor (''Varanus mabitang'') is an endangered monitor lizard native to Panay Island in the Philippines. Unlike most monitors, it is a specialized frugivore. Distribution and habitat The Panay monitor occurs only on Panay, inhabiting ...

'', and ''

Varanus bitatawa The Northern Sierra Madre forest monitor (''Varanus bitatawa''), also known by the local names ''bitatawa'', ''baritatawa'', and ''butikaw'', is a large, arboreal, frugivorous lizard of the genus '' Varanus''. Description The forest monitor li ...

'') are primarily frugivores. Among species of living varanids, the limbs show positive

allometry Allometry (Ancient Greek "other", "measurement") is the study of the relationship of body size to shape, anatomy, physiology and behaviour, first outlined by Otto Snell in 1892, by D'Arcy Thompson in 1917 in ''On Growth and Form'' and by Jul ...

, 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
/ref>

References

External links