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 phylogenetic tree below shows the relationships among the Ramphastidae, according to a 2023 study by Emily Ostrow and collaborators. 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.
History The evolutionary history of toucans can be traced back to the
Eocene period, around 50 million years ago, the first toucan-like bird, may have appeared in Europe. The modern toucan species, however, originated in South America during the
Miocene period, around 23 million years ago.
Transposable Elements 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 green-billed toucan (
Ramphastos dicolorus) 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.
Species The genus contains seven species:
Former species 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) • Citron-throated toucan is now treated as subspecies of the
channel-billed toucan (
Ramphastos vitellinus citreolaemus) ==Description==