The Ramphastos genus, also known as toucans, is a genus of brightly colored, tropical birds that are found throughout Central and South America from Southern Mexico to the southern cone of the South American continent. Toucans are typically characterized by their large, colorful bills, which are used for a variety of functions such as thermoregulation, feeding, and social signaling.
|Ramphastos tucanus (white-throated toucan)|
The genus Ramphastos was introduced in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae. The name is from Ancient Greek ῥαμφηστης/rhamphēstēs meaning "snouted" (from ῥαμφη/rhampē meaning "bill"). The type species was later designated by Nicholas Aylward Vigors as the white-throated toucan (Ramphastos tucanus).
The genus contains eight species:
|Image||Common Name||Scientific name||Distribution|
|Green-billed toucan||Ramphastos dicolorus||Eastern Brazil, Pantanal of Bolivia, eastern Paraguay and far north-eastern Argentina|
|Channel-billed toucan||Ramphastos vitellinus||Trinidad and in tropical South America as far south as southern Brazil and central Bolivia|
|Citron-throated toucan||Ramphastos citreolaemus||Northern Colombia and north-western Venezuela|
|Choco toucan||Ramphastos brevis||Chocó forests in western Ecuador and western Colombia|
|Keel-billed toucan||Ramphastos sulfuratus||Southern Mexico to Venezuela and Colombia|
|Toco toucan||Ramphastos toco||Northern and eastern Bolivia, extreme south-eastern Peru, northern Argentina, eastern and central Paraguay, eastern and southern Brazil|
|White-throated toucan||Ramphastos tucanus||The Amazon Basin including the adjacent Tocantins and Araguaia River drainage|
|Yellow-throated toucan||Ramphastos ambiguus||Central and northern South America|
Some authorities, either presently or formerly, recognize additional species or subspecies as species belonging to the genus Ramphastos including:
- Green aracari (as Ramphastos viridis)
- Ivory-billed aracari (as Ramphastos Azara)
- Black-necked aracari (as Ramphastos Aracari)
- Black-necked aracari (atricollis) (as Ramphastos atricollis)
- Collared aracari (as Ramphastos torquatus)
- Saffron toucanet (as Ramphastos Bailloni)
This genus comprises the largest toucans, ranging from 42 to 61 centimetres (17 to 24 in) in length. All have black wings, tails and thighs, but the colour of the remaining plumage depends on the exact species involved.
Diversity of billsEdit
(Ramphastos vitellinus vitellinus)
Green-billed toucan (Ramphastos dicolorus)
(Ramphastos ambiguus swainsonii)
White-throated toucan, (Ramphastos tucanus)
Distribution and habitatEdit
Toucans are found throughout Central and South America, from southern Mexico to northern Argentina. They inhabit a variety of ecosystems, including tropical rainforests, cloud forests, and savannas. Toucans are particularly abundant in the Amazon basin, where they play an important ecological role as seed dispersers and predators.
One study published in the journal PLOS ONE in 2016, investigated the genetic diversity and geographic distribution of the keel-billed toucan (Ramphastos sulfuratus), a species that is found throughout Central America. The researchers used mitochondrial DNA sequences to analyze the genetic diversity of 104 keel-billed toucans from 17 different locations across their range. The study found that the keel-billed toucan had low levels of genetic diversity, which was likely due to historical population bottlenecks and range expansions. The study also identified two distinct genetic clusters of keel-billed toucans, which corresponded to populations in the Caribbean and Pacific regions of Central America, respectively.
Behavior and ecologyEdit
They are arboreal and nest in tree holes laying 2–4 white eggs.
Food and feedingEdit
All the species are basically fruit-eating, but will take insects and other small prey.
The ischnoceran louse Austrophilopterus cancellosus is suspected to parasitize all species of Ramphastos toucans. Its presence has been confirmed on all species except the citron-throated toucan.
The phylogenetic relationships among toucans have been the subject of ongoing debate and research; in the past, the eight toucan species were classified into different subfamilies based on their bill size and shape. However, recent molecular studies have suggested that toucans are more closely related to aracaris and toucanets than previously thought. Several species have also been removed from the Ramphastos genus: Green aracari, Ivory-billed aracari, Black-necked aracari, Black-necked aracari, Collared aracari, Saffron toucanet.
One such study published in the journal Molecular Phylogenetics and Evolution in 2015, used molecular data to investigate the phylogenetic relationships among toucans. The researchers sequenced several nuclear and mitochondrial genes from 40 toucan species, representing all recognized subgenera within the genus Ramphastos. The study found that toucans could be divided into six distinct clades, each with different bill morphologies and geographic distributions. The study also suggested that the toucan genus had diversified during the Pliocene epoch, around 5 million years ago, with the rapid diversification of several lineages during the Pleistocene epoch, around 1 million years ago.
The Ramphastos genus is divided into two groups which differ in the shape of their bills and their vocalization patterns. These two groups are known colloquially as the “croakers'' and the “yelpers”. The “croakers'' contain the following: R. brevis, R. dicolorus, R. sulfuratus, R. toco, and R. vitellinus. The “yelper” group contains: R. ambiguous and R. tucanus. Of these, R. brevis and R. dicolorus are polytypic.
The evolutionary history of toucans can be traced back to the Eocene period, around 50 million years ago, when the first toucan-like bird, known as Paratodus, appeared in Europe. The modern toucan species, however, originated in South America during the Miocene period, around 23 million years ago.
Transposable elements are a major source of genetic diversity and can contribute to the evolution of new genes and regulatory elements. Transposable elements have been found in the genomes of all organisms studied so far, including the Ramphastos genus.
One study published in the journal Genome Biology in 2018, used a combination of genomic and phylogenetic analyses to investigate the role of transposable elements in the evolution of toucans. The researchers sequenced the genome of the toco toucan (Ramphastos toco) and compared it to the genomes of other bird species. They found that transposable elements were abundant in the toucan genome, making up approximately 19% of the genome.
The researchers also identified several families of transposable elements that were specific to toucans, indicating that these elements had played a role in the evolution of the toucan genome. In particular, the researchers identified a family of elements called CR1, which had undergone a burst of activity in the toucan genome. This burst of activity was associated with the expansion and diversification of several gene families that are involved in sensory perception and immune response.
The study also found that transposable elements had contributed to the evolution of the toucan bill, which is one of the most distinctive features of toucans. The researchers identified several genes involved in the development of the bill that had been influenced by these elements. In particular, they found that they had inserted into regulatory regions of the genes, altering their expression patterns and contributing to the development of the large and colorful bill.
- ^ Linnaeus, Carl (1758). Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1 (10th ed.). Holmiae (Stockholm): Laurentii Salvii. p. 103.
- ^ Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 330. ISBN 978-1-4081-2501-4.
- ^ Vigors, Nicholas Aylward (1826). "On some species of the Ramphastidae". Zoological Journal. 2: 466–483 .
- ^ Peters, James Lee, ed. (1948). Check-List of Birds of the World. Vol. 6. Cambridge, Massachusetts: Harvard University Press. p. 82.
- ^ Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (July 2021). "Woodpeckers". IOC World Bird List Version 11.2. International Ornithologists' Union. Retrieved 10 August 2021.
- ^ "Pteroglossus viridis – Avibase". avibase.bsc-eoc.org. Retrieved 2016-12-26.
- ^ "Pteroglossus azara – Avibase". avibase.bsc-eoc.org. Retrieved 2016-12-26.
- ^ "Pteroglossus aracari – Avibase". avibase.bsc-eoc.org. Retrieved 2016-12-26.
- ^ "Pteroglossus aracari atricollis – Avibase". avibase.bsc-eoc.org. Retrieved 2016-12-26.
- ^ "Pteroglossus torquatus – Avibase". avibase.bsc-eoc.org. Retrieved 2016-12-26.
- ^ "Pteroglossus bailloni – Avibase". avibase.bsc-eoc.org. Retrieved 2016-12-27.
- ^ a b Short, L. L., & Horne, J. F. M. (2002). Toucans (Ramphastidae). pp. 220–272 in del Hoyo, J., Elliott, A., & Sargatal, J. eds. (2002). Handbook of the Birds of the World. Vol. 7 Jacamars to Woodpecker. Lynx Edicions, Barcelona. ISBN 84-87334-37-7
- ^ van de Ven, T. M. F. N.; Martin, R. O.; Vink, T. J. F.; McKechnie, A. E.; Cunningham, S. J. (2016-05-18). Romanovsky, Andrej A. (ed.). "Regulation of Heat Exchange across the Hornbill Beak: Functional Similarities with Toucans?". PLOS ONE. 11 (5): e0154768. doi:10.1371/journal.pone.0154768. ISSN 1932-6203.
- ^ Price, Roger D. & Weckstein, Jason D. (2005). The genus Austrophilopterus Ewing (Phthiraptera: Philopteridae) from toucans, toucanets, and araçaris (Piciformes: Ramphastidae). Zootaxa 918: 1–18. PDF fulltext
- ^ Patané, José S.L.; Weckstein, Jason D.; Aleixo, Alexandre; Bates, John M. (December 2009). "Evolutionary history of Ramphastos toucans: Molecular phylogenetics, temporal diversification, and biogeography". Molecular Phylogenetics and Evolution. 53 (3): 923–934. doi:10.1016/j.ympev.2009.08.017.
- ^ Manthey, Joseph D; Moyle, Robert G; Boissinot, Stéphane (June 2018). "Multiple and Independent Phases of Transposable Element Amplification in the Genomes of Piciformes (Woodpeckers and Allies)". Genome Biology and Evolution. 10 (6): 1445–1456. doi:10.1093/gbe/evy105. ISSN 1759-6653. PMC 6007501. PMID 29850797.