Anolis
Temporal range: Early Miocene–present
Green anole
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Iguania
Family: Dactyloidae
Genus: Anolis
Daudin, 1802
Species

circa 425 spp., see text

Anolis is a genus of anoles (US: /əˈn.liz/ (audio speaker iconlisten)), iguanian lizards in the family Dactyloidae, native to the Americas. With more than 425 species,[1] it represents the world's most species-rich amniote tetrapod genus, although many of these have been proposed to be moved to other genera, in which case only about 45 Anolis species remain.[2][3] Previously, it was classified under the family Polychrotidae that contained all the anoles, as well as Polychrus, but recent studies place it in the Dactyloidae.[2]

Taxonomy

See also: Dactyloidae § Genera

This very large genus displays considerable paraphyly, but phylogenetic analysis suggests a number of subgroups or clades.[2][4] Whether these clades are best recognized as subgenera within Anolis or separate genera remains a matter of dispute.[2][3][5]

If the clades are recognized as full genera, about 45 species remain in Anolis, with the remaining moved to Audantia (9 species), Chamaelinorops (7 species), Ctenonotus (more than 40 species), Dactyloa (circa 95 species), Deiroptyx (almost 35 species), Norops (about 190 species), and Xiphosurus (around 15 species).[2][3] 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).[6] Among the subgroups within Anolis are:

In 2011, the green (or Carolina) anole (Anolis carolinensis) became the first reptile to have its complete genome published.[7]

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.[8][9]

Ecomorphs

Main article: Anolis ecomorph

Anolis lizards are some of the best examples of both adaptive radiation and convergent evolution. Populations of lizards on isolated islands diverge to occupy separate ecological niches, 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).[10] These divergences in habitat 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.[10][11] This demonstrates adaptive radiation can actually be predictable based on habitat encountered, and experimental introductions onto formerly lizard-free islands have proven Anolis evolution can be predicted.[12][13][14][15]

After appearing on each of the four Greater Antillean Islands about 50 million years ago, Anolis lizards spread on each island to occupy niches in the island's trees. Some living in the tree canopy area, others low on the tree trunk near the ground; others in the mid-trunk area, others on twigs. Each new species developed its own distinct body type, called an ecomorph, adapted to the tree niche where it lived. Together, the different species occupied their various niches in the trees as a "community". 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.[16][17]

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.[18] 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.[19]   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

Main article: List of Anolis lizards

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.[20]

References

  1. ^ Uetz, P.; Hallermann, J. (2018). "Dactyloidae". The Reptile Database. Retrieved 5 November 2018.
  2. ^ a b c d e Nicholson, Kirsten E.; Crother, Brian I.; Guyer, Craig; Savage, Jay M. (2012). "It is time for a new classification of anoles (Squamata: Dactyloidae)" (PDF). Zootaxa. 3477 (1): 1–108, page 38. doi:10.11646/zootaxa.3477.1.1. Archived (PDF) from the original on 30 January 2016. Abstract
  3. ^ a b c Nicholson, K.A.; B.I. Crother; C. Guyer; J.M. Savage (2018). "Translating a clade based classification into one that is valid under the international code of zoological nomenclature: the case of the lizards of the family Dactyloidae (Order Squamata)". Zootaxa. 4461 (4): 573–586. doi:10.11646/zootaxa.4461.4.7. PMID 30314068. S2CID 52975031.
  4. ^ Glor, Richard E.; Jonathan, B. Losos; Larson, Allan (2005). "Out of Cuba: overwater dispersal and speciation among lizards in the Anolis carolinensis subgroup" (PDF). Molecular Ecology. 14 (8): 2419–2432. doi:10.1111/j.1365-294X.2005.02550.x. PMID 15969724. S2CID 20092906.
  5. ^ Poe; Nieto-Montes de Oca; Torres-Carvajal; Queiroz; Velasco; Truett; Gray; Ryan; Köhler; Ayala-Varela; Latella (2017). "A Phylogenetic, Biogeographic, and Taxonomic study of all Extant Species of Anolis (Squamata; Iguanidae)". Systematic Biology. 66 (5): 663–697. doi:10.1093/sysbio/syx029. PMID 28334227.
  6. ^ Nicholson 2012, p. 17
  7. ^ Sweetlove, Lee (2011-08-31). "Lizard genome unveiled". Nature. doi:10.1038/news.2011.512.
  8. ^ Losos, J. B. (2009). Lizards in an evolutionary tree: ecology and adaptive radiation of anoles. University of California Press, Berkeley, CA.
  9. ^ Hertz, P.E.; Arima, Y.; Harrison, A.; Huey, R.B.; Losos, J.B.; Glor, R.E. (2012). "Asynchronous evolution of physiology and morphology in Anolis lizards". Org. Evol. 67 (7): 2101–2113. doi:10.1111/evo.12072. PMID 23815663. S2CID 2793493.
  10. ^ a b Losos, J.B. (2007). "Detective work in the West Indies: integrating historical and experimental approaches to study island lizard evolution" (PDF). BioScience. 57 (7): 585–597. doi:10.1641/b570712. S2CID 6869606.
  11. ^ Losos, J. B.; Jackman, T. R.; Larson, A.; de Queiroz, K.; Rodriguez-Schettino, L. (1998). "Contingency and determinism in replicated adaptive radiations of island lizards". Science. 279 (5359): 2115–2118. Bibcode:1998Sci...279.2115L. doi:10.1126/science.279.5359.2115. PMID 9516114.
  12. ^ Calsbeek, R (2008). "Experimental evidence that competition and habitat use shape the individual fitness surface". Journal of Evolutionary Biology. 22 (1): 97–108. doi:10.1111/j.1420-9101.2008.01625.x. PMID 19120813. S2CID 25745447.
  13. ^ Calsbeek, R.; Buermann, W.; Smith, T.B. (2009). "Parallel shifts in ecology and natural selection in an island lizard". BMC Evolutionary Biology. 9: 3. doi:10.1186/1471-2148-9-3. PMC 2630972. PMID 19126226.
  14. ^ Calsbeek, R.; Cox, R.M. (2010). "Experimentally assessing the relative importance of predation and competition as agents of selection". Nature. 465 (7298): 613–616. Bibcode:2010Natur.465..613C. doi:10.1038/nature09020. PMID 20453837. S2CID 4326027.
  15. ^ Calsbeek, R.; Smith, T.B. (2007). "Probing the adaptive landscape using experimental islands: density-dependent natural selection on lizard body size". Evolution. 61 (5): 1052–1061. doi:10.1111/j.1558-5646.2007.00093.x. PMID 17492960. S2CID 4643163.
  16. ^ "Trapped in Amber: Ancient fossils reveal remarkable stability of Caribbean lizard communities". 27 July 2015. Retrieved 2015-07-28.
  17. ^ Sherratt, Emma; Castañeda, María del Rosario; Garwood, Russell J.; Mahler, D. Luke; Sanger, Thomas J.; Herrel, Anthony; Queiroz, Kevin de; Losos, Jonathan B. (2015-07-27). "Amber fossils demonstrate deep-time stability of Caribbean lizard communities". Proceedings of the National Academy of Sciences. 112 (32): 9961–9966. Bibcode:2015PNAS..112.9961S. doi:10.1073/pnas.1506516112. ISSN 0027-8424. PMC 4538666. PMID 26216976.
  18. ^ Muñoz, Martha M.; Stimola, Maureen A.; Algar, Adam C.; Conover, Asa; Rodriguez, Anthony J.; Landestoy, Miguel A.; Bakken, George S.; Losos, Jonathan B. (2014-03-07). "Evolutionary stasis and lability in thermal physiology in a group of tropical lizards". Proceedings of the Royal Society B: Biological Sciences. 281 (1778): 20132433. doi:10.1098/rspb.2013.2433. ISSN 0962-8452. PMC 3906933. PMID 24430845.
  19. ^ Muñoz, Martha M.; Losos, Jonathan B. (January 2018). "Thermoregulatory Behavior Simultaneously Promotes and Forestalls Evolution in a Tropical Lizard". The American Naturalist. 191 (1): E15–E26. doi:10.1086/694779. ISSN 0003-0147. PMID 29244559. S2CID 3918571.
  20. ^ Fitch, H.S.; Hillis, D.M. (1984). "The anolis dewlap: Interspecific variability and morphological associations with habitat". Copeia. 1984 (2): 315–323. doi:10.2307/1445187. JSTOR 1445187.

Further reading