Grallaria alvarezi Cuervo, Cadena, Isler, & Chesser, 2020

Isler, Morton L., Chesser, Terry, Robbins, Mark B., Cuervo, Andrés M., Cadena, Carlos Daniel & Hosner, Peter A., 2020, Taxonomic evaluation of the Grallaria rufula (Rufous Antpitta) complex (Aves: Passeriformes: Grallariidae) distinguishes sixteen species, Zootaxa 4817 (1), pp. 1-74 : 13-14

Grallaria alvarezi Cuervo, Cadena, Isler, & Chesser , new species

Chamí Antpitta

Includes the population designated rufula 4 in the analysis.

Diagnosis. Overall plumage deep reddish-brown, deeper in color than other taxa, especially in the throat and underparts. Vocalizations of G. alvarezi ( Fig. 6 ) are distinguished from those of all other taxa in the complex, except G. saturata , by a short song that consists of a single note, followed by a longer interval and ending with a trill. Short songs of G. alvarezi differ diagnosably from those of G. saturata by rounded rather than flat or downslurred notes, and the trill in the short song of G. alvarezi lacks the interruption found in the southern population of G. saturata . Peak frequencies of notes in long songs of G. alvarezi decline, whereas those of G. saturata remain nearly constant. In addition, typical notes of long songs of G. alvarezi are box-shaped and have a narrow band width, whereas those of G. saturata are typically downslurred and have a wider band width, although less commonly they approach the shape of G. alvarezi notes, especially in extended songs.

Distribution. Endemic to Colombia in Western Andes from Paramillo, northwestern Antioquia, south to northwestern Cauca, 2350–3650 m.

Holotype. Instituto Alexander von Humboldt (IAvH-A) 13358, prepared as round skin and partial body in fluid, with frozen tissue samples number IAvH-CT-3997. Adult female mist-netted in upper montane wet forest on 23 August 2004 by M. A. Echeverry, S. Córdoba, S. Sierra (collector field number MAE-431, mist-net format number 89) in Colombia, Dpto. Risaralda, mpio. Pueblo Rico , vda. La Cumbre, PNN Tatamá (5°9’29”N, 76°1’0”W, elevation 2620–2680 m).

Description of holotype. Adult female. Overall plumage color intense reddish brown (2.5YR 3/4), especially on crown, nape, mantle, rump and rectrices, and ventrally on throat, sides of neck, upper flanks, and thighs. Facial area including orbital feathers, lores and auriculars also reddish brown (2.5YR 3/4). The breast shows an even more intense saturation of reddish brown (close to 2.5YR 3/4 but more saturated), which suggests a diffuse breast band that grades towards lighter buffy brown (7.5YR 6/6–6/8) at center of belly, particularly at the outer portion of vanes of contour feathers, with inner portions duskier (close to 7.5YR 5/8), giving an appearance of a scaled pattern in lower belly; vent and outer tail coverts slightly paler (7.5YR 7/6). Reddish-brown (5YR 3/4–3/6) on wings mostly due to coloration of outer webs of remiges and wing coverts, whereas inner webs are slightly duskier (5YR 3/2). Axillaries, lesser and median underwing coverts reddish brown (5YR 5/6–5/8). Greater underwing coverts dusky brown (close to 5YR 3/2) with rufescent outer borders (7.5YR 6/8). Ovary 9 x 4.1 mm, largest follicle 1.2 x 2.0 mm in postovulatory regression, skull 100% pneumatized, abundant fat, no molt. Stomach, syrinx and other organs unexamined but saved intact as partial liquid specimen in ethanol (IAvH-A 13358, MAE-431). Soft part coloration (parentheses in Spanish as originally annotated on label): iris brown (“marrón”), maxilla dusky black (“cuerno oscuro”), mandible dusky black with buffy base and pale tip (“base crema, punta clara, resto cuerno”), feet/legs grayish blue (“azul grisáceo”).

Measurements of holotype. Bill length (total) 23.04 mm, exposed culmen 20.5 mm, bill from nares 12.49 mm, bill width 5.27 mm, bill depth 6.01 mm, wing length (chord) 81.22 mm, flattened wing length 84 mm, tarsus length 43.23 mm, tail length 37.08 mm.

Paratypes. USNM 436485 (female) , AMNH 133533 (female) , LACM 37383 (female) , FMNH 249750 (fe- male) , AMNH 109634 (immature male) , AMNH 109635 (female) (specimen photographs App. 6, Figs. A19 and A34) .

Variation in plumage. Most specimens show pale streaking in the centers of some contour feathers, and in some the intensity of breast feathers suggests a diffuse band.

Etymology. The scientific name honors Colombian ornithologist Mauricio Álvarez Rebolledo, who led several biological expeditions during the peak of political instability of the 1990s and early 2000s in Colombia, while playing an important role in conservation and education. Mauricio pioneered avian sound recording in the country, establishing the Colección de Sonidos Ambientales at Instituto Alexander von Humboldt. The English name honors the “people of the mountains,” the Emberá-Chamí indigenous community inhabiting the slopes of northern Western Andes of Colombia. Chamí means mountain, and Tatamá, the name of the type locality, means “the grandfather of the rivers” in Emberá language.

Remarks. With larger samples of G. saturata from the Central Andes and from southern Colombia in Nariño, it appears that additional vocal characters may be found to differ diagnostically between G. alvarezi and G. saturata . These include the change in pace and intensity in long songs and duration of note intervals in short songs. The rufous coloration of G. alvarezi is among the darkest and most intense of any population in the complex save G. blakei and G. centralis ; consequently, the plumage of G. alvarezi is distinct from its geographical neighbor G. saturata . The northern range limit of this new species are the peaks of PNN Paramillo, but determining the southern boundary awaits additional field work. We had no specimens in fresh plumage nor vocal recordings from south of PNN Tatamá in western Risaralda. Specimens from Farallones de Cali and Cerro Munchique appear to be even darker than the type series in Risaralda and Antioquia. Field work in the isolated upper montane forests and treeline of the Western Andes in Cerro Calima, Farallones de Cali, and Cerro Munchique would help elucidate the range limits of this species, and of G. saturata . A single vocal recording attributed to Cerro Munchique appears to be of G. saturata , but the precise location of the recording (slope and elevation) is unknown.

Figures

FIGURE 6. Songs of Grallaria alvarezi: (A) long song, Páramo de Frontino, Antioquia, Colombia (Krabbe XC27437); (B) short song, Alto de Ventanas, Antioquia (Calderón-F. XC104251).

FIGURE 19. Map showing the taxonomy and distribution of the Grallaria rufula complex as revised herein, Part 1: populations formerly ascribed to G. rufula. Solid circles represent sectors (Isler 1997) that contain locations of genetic samples used in a companion paper (Chesser et al. 2020) and stars that are sectors containing locations where specimens have been collected or vocalizations recorded. Sectors may contain more than one genetic or vocal sample or specimen. Lines encompass sectors attributed to the same taxon and are not projections of geographic range. Some sectors are placed away from boundary lines (country boundaries, coasts) for clarity which results in discrepancies with geographic range projections which can be found in the companion paper (Chesser et al. 2020).