Friday, December 15, 2017

[Ornithology • 2018] Myrmoderus eowilsoni • A New Species of Antbird (Passeriformes: Thamnophilidae) from the Cordillera Azul, San Martín, Peru

Myrmoderus eowilsoni 
Moncrieff, Johnson, Lane, Beck, Angulo & Fagan, 2018

We describe distinctive new species of antbird (Passeriformes: Thamnophilidae) from humid montane forest (1,340–1,670 m above sea level) of the Cordillera Azul, San Martín Region, Peru. Plumage, voice, and molecular evidence distinguish this species from its sister taxon Myrmoderus ferrugineus (Ferruginous-backed Antbird), which is found in lowland Amazonian rainforests of the Guiana Shield and Madeira-Tapajós interfluvium. The new species is presently known only from one ridge in the Cordillera Azul, and therefore we recommend further fieldwork to better estimate its distribution and population size.

Keywords: MyrmecizaMyrmoderus, new species, outlying ridges, taxonomy

A male Cordillera Azul Antbird.
Photo: A. Spencer

FIGURE 2 Ventral (A) and lateral (B) views of both species of Myrmoderus.
 Left to right: male M. eowilsoni (CORBIDI 12381; holotype), female M. eowilsoni (CORBIDI 12380; mate of holotype), male M. ferrugineus (LSUMZ 178458), and female M. ferrugineus (LSUMZ 178456). Scale bars = 5 cm.

Myrmoderus eowilsoni, species novum
Cordillera Azul Antbird
Hormiguero de la Cordillera Azul (Spanish)

Diagnosis: We assign Myrmoderus eowilsoni to the genus Myrmoderus on the basis of its combination of black ear coverts, extensively rufous brown plumage, and blackish wing coverts with broad white or buff tips (see Isler et al. 2013). Additional characters shared with M. ferrugineus include bluish bare orbital skin, gray feet and tarsi, lack of white interscapular patch, and terrestrial walking behavior. Despite these similarities, it is readily distinguishable from M. ferrugineus by (1) crown and nape color, (2) supercilium color, (3) extent of bare orbital skin, (4) belly color, (5) breast color (females), and (6) song (Figures 2 and 3). Compared to M. ferrugineus, the new species has a colder brown crown and nape, a gray rather than white supercilium, and less extensive bluish bare orbital skin. The belly of M. eowilsoni is black (males) or dark brown (females), whereas both sexes of M. ferrugineus show substantial white in this area. Additionally, females of M. eowilsoni have a rufous breast, whereas females of M. ferrugineus have a black breast (Figure 2A). The song differs substantially from M. ferrugineus by having fewer notes and a slower pace.

Etymology: We name Myrmoderus eowilsoni in honor of Dr. Edward Osborne Wilson to recognize his tremendous devotion to conservation and his patronage of the Rainforest Trust, which strives to protect the most imperiled species and habitats in the Neotropics and across the globe. We select the English name to draw attention to the little known but biogeographically important and biodiverse mountain range that contains the type locality of the species.

Andre E. Moncrieff, Oscar Johnson, Daniel F. Lane, Josh R. Beck, Fernando Angulo and Jesse Fagan. 2018. A New Species of Antbird (Passeriformes: Thamnophilidae) from the Cordillera Azul, San Martín, Peru [Una nueva especie de hormiguero (Passeriformes: Thamnophilidae) de la Cordillera Azul, San Martín, Perú]. The Auk.  135(1); 114-126. DOI: 10.1642/AUK-17-97.1

RESUMEN: Describimos una nueva y distintiva especie de hormiguero (Passeriformes: Thamnophilidae) de los bosques montanos húmedos (1,340–1,670 metros sobre el nivel del mar) de la Cordillera Azul, región de San Martín, Perú. El plumaje, la voz, y la evidencia molecular distinguen a esta especie de su taxón hermano Myrmoderus ferrugineus (Hormiguero Lomirrufo), el cual se encuentra en los bosques tropicales amazónicos de llanura del Escudo Guyanés y el interfluvio Madeira-Tapajós. A esta nueva especie se le conoce en la actualidad únicamente de una cresta de la Cordillera Azul, y por lo tanto, recomendamos mayor investigación de campo para poder estimar mejor su distribución y el tamaño de su población.
Palabras clave: cadenas montañosas aisladas, Myrmeciza, Myrmoderus, nueva especie, taxonomía

New antbird species discovered in Peru
New Bird Species Named for E.O. Wilson, “Father of Biodiversity” and Rainforest Trust Board Me…   @rainforesttrust

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