''Anolis'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
anole
Dactyloidae are a family of lizards commonly known as anoles () and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat it as a subfami ...
s (),
iguanian lizards in the family
Dactyloidae
Dactyloidae are a family of lizards commonly known as anoles () and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat it as a subfami ...
, native to the
Americas
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World.
Along with th ...
. With more than 425 species,
it represents the world's most species-rich
amniote
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are disti ...
tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
genus, although many of these have been proposed to be moved to other genera, in which case only about 45 ''Anolis'' species remain.
[Abstract]
/ref>Polychrus
''Polychrus'' is the only extant genus of polychrotid lizards in the world. Commonly called bush anoles, they are found in Central and South America, as well as nearby Trinidad and Tobago.
''Polychrus'' means "many colored". True anoles in oth ...
'', but recent studies place it in the Dactyloidae.[
]
Taxonomy
This very large genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
displays considerable paraphyly
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
, but phylogenetic analysis suggests a number of subgroups or clades
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, t ...
.[ Some of these can be further subdivided. For example, ''Phenacosaurus'' was often listed as a full genus in the past, but it is a subclade within ''Dactyloa'' (''Dactyloa heteroderma'' species group). Among the subgroups within ''Anolis'' are:
* '']carolinensis
The ''Anolis carolinensis'' series is a proposed clade or subgroup of closely related mid-sized trunk crown anoles () within the genus ''Anolis''. It was created by Nicholson ''et al''. in 2012 and defined as containing 13 species, a few examples ...
'' species group (13 species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
)
* ''isolepis'' species group (three species)
In 2011, the green (or Carolina) anole (''Anolis carolinensis'') became the first reptile to have its complete genome published.
Closely related, recently diverged anole lizards exhibited more divergence in thermal biology than in morphology. These anole lizards are thought to have the same structural niche and have similarities in their size and shape, but they inhabit different climatic niches with was variability in temperature and openness of the environment. This suggests that thermal physiology is more associated with recently diverged anole lizards.
Ecomorphs
''Anolis'' lizards are some of the best examples of both adaptive radiation
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic int ...
and convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
. Populations of lizards on isolated islands diverge to occupy separate ecological niches
In ecology, a niche is the match of a species to a specific environmental condition.
Three variants of ecological niche are described by
It describes how an organism or population responds to the distribution of resources and competitors (for ...
, mostly in terms of the location within the vegetation where they forage (such as in the crown of trees vs. the trunk vs. underlying shrubs).habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
are accompanied by morphological changes primarily related to moving on the substrate diameter they most frequently encounter, with twig ecomorphs having short limbs, while trunk ecomorphs have long limbs.
In addition, these patterns repeat on numerous islands, with animals in similar habitats converging on similar body forms repeatedly.ecomorph Ecomorphology or ecological morphology is the study of the relationship between the ecological role of an individual and its morphological adaptations. The term "morphological" here is in the anatomical context. Both the morphology and ecology exh ...
, adapted to the tree niche where it lived. Together, the different species occupied their various niches in the trees as a "community
A community is a social unit (a group of living things) with commonality such as place, norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area (e.g. a country, village, tow ...
". A study of lizard fossils trapped in amber shows that the lizard communities have existed for about 20 million years or more. Four modern ecomorph body types, trunk-crown, trunk-ground, trunk, and twig, are represented in the amber fossils study. Close comparison of the lizard fossils with their descendants alive today in the Caribbean shows the lizards have changed little in the millions of years.
Behavior
As ectotherms, ''Anolis'' lizards must regulate their body temperature partly through behavioral changes and bask in the sunlight to gain enough heat to become fully active, but lizards cannot behaviorally warm themselves at night when temperatures drop. Because of this, cold tolerance evolves faster than heat tolerance in these lizards. On the island of Hispanola, both high-altitude and low-altitude lizard populations exist, and the thermal conditions at high and low elevations differ significantly. High-altitude lizards have shifted their ecological niche to boulder environments, where warming themselves is easier, and they show changes in the shape of limbs and skull that make them better adapted to these environments.
Species
The ''Anolis'' lizards that are less susceptible to predation are those with a dewlap in which both the scales and the exposed skin areas between them match the usual pale gray or whitish of the rest of the ventral surface.
References
Further reading
*
External links
Anole Annals
a blog written and edited by scientists who study ''Anolis'' lizards
''Anolis''
The Reptile Database
Adapting Anolis
short film on adaptations of Cuba's ''Anolis'' lizards
{{Authority control
A
Lizard genera
Taxa named by François Marie Daudin
Fauna of the Dominican Republic