<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1870-7459</journal-id>
<journal-title><![CDATA[Huitzil]]></journal-title>
<abbrev-journal-title><![CDATA[Huitzil]]></abbrev-journal-title>
<issn>1870-7459</issn>
<publisher>
<publisher-name><![CDATA[Sociedad para el Estudio y Conservación de las Aves en México, A.C. (CIPAMEX)]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1870-74592020000200014</article-id>
<article-id pub-id-type="doi">10.28947/hrmo.2020.21.2.511</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[A strong case of dilution in the Yellow-throated Toucan (Ramphastos ambiguus)]]></article-title>
<article-title xml:lang="es"><![CDATA[Un fuerte caso de dilución en el tucán de garganta amarilla (Ramphastos ambiguus)]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Mora]]></surname>
<given-names><![CDATA[José Manuel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[López Umaña]]></surname>
<given-names><![CDATA[Lucía I.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Técnica Nacional  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Costa Rica</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Técnica Nacional  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Costa Rica</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2020</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2020</year>
</pub-date>
<volume>21</volume>
<numero>2</numero>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1870-74592020000200014&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1870-74592020000200014&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1870-74592020000200014&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Plumage color aberrations are common in birds, but often it is difficult or even impossible to identify them properly in the field. Several of these aberrations are common, especially progressive greying, leucism and INO, although there is confusion among the different mechanisms. Other aberrations are rare or infrequently reported. Dilution, for example, refers to a reduced concentration of melanin granules that dilutes the color, although the pigment itself is not changed. It affects the entire plumage, rather than single feathers. The Yellow-throated Toucan (Ramphastos ambiguus) is predominantly black, and has feathers with brown tips, red under the tail coverts, and feathers above the tail are cream colored. It has a yellow bib covering the throat and chest with red band countering it, and the skin of the face is chartreuse. The Yellow-throated Toucan is most notable for its massive, bicolored bill. Here we report an apparent strong case of dilution in the Yellow-throated Toucan. An individual observed at La Unión, Guápiles on the Caribbean versant of Costa Rica on 10 October 2019 almost lacked melanin, but retained carotenoids. The tertials and some feathers on the rump were very light grey, suggesting strong dilution. We also discuss other possible explanations for this amazing coloration.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen Las aberraciones de color del plumaje son comunes en las aves, pero a menudo es difícil o incluso imposible identificarlas adecuadamente en el campo. Varias de estas aberraciones son comunes, en especial el encanecimiento progresivo, el leucismo y el INO, aunque existe confusión entre los diferentes mecanismos. Otras aberraciones son raras o poco frecuentes, por ejemplo, la dilución, que es la concentración de gránulos de melanina que diluyen el color, aunque el pigmento en sí no cambia. La dilución afecta a todo el plumaje. El tucán de garganta amarilla (Ramphastos ambiguus) es predominantemente negro y tiene plumas con puntas ma­ rrón, plumas rojas debajo de las coberteras de la cola y las plumas sobre la cola son de color crema. Tiene un babero amarillo que cubre la garganta y el pecho con una banda roja que lo rodea y la piel de la cara es color cartujo. El tucán de garganta amarilla es notable por su enorme pico bicolor. Aquí informamos sobre un aparente fuerte caso de dilución en el tucán de garganta amarilla. Un individuo que observamos en La Unión de Guápiles en la vertiente caribe de Costa Rica el 10 de octubre de 2019, carecía casi por completo de melanina, pero conservaba los carotenoides. Las terciarias y algunas plumas en la rabadilla eran de color gris muy claro, lo que sugiere una fuerte dilución. También discutimos otras posibles explicaciones para esta increíble coloración.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[color aberration]]></kwd>
<kwd lng="en"><![CDATA[Costa Rica]]></kwd>
<kwd lng="en"><![CDATA[genetic mutation]]></kwd>
<kwd lng="en"><![CDATA[heritable disorders]]></kwd>
<kwd lng="en"><![CDATA[leucism]]></kwd>
<kwd lng="es"><![CDATA[aberración cromática]]></kwd>
<kwd lng="es"><![CDATA[Costa Rica]]></kwd>
<kwd lng="es"><![CDATA[desórdenes heredables]]></kwd>
<kwd lng="es"><![CDATA[leucismo]]></kwd>
<kwd lng="es"><![CDATA[mutación genética]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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