Turdus leucomelas upichiarum, Stiles & Avendaño, 2019

Stiles, F. Gary & Avendaño, Jorge Enrique, 2019, Distribution and status of Turdus thrushes in white-sand areas of eastern Colombia, with a new subspecies of T. leucomelas, Zootaxa 4567 (1), pp. 161-175 : 164-166

Turdus leucomelas upichiarum , ssp. nov .

Holotype. ICN no. 39668 ( Fig. 3 ), adult male, collected by F. G. Stiles on 21 February 2017 (original number FGS 4652). Skull 100% ossified, trace of fat. Left testis 15x9, right 9x 7 mm; large cloacal protuberance; plumage fresh, no molt. Stomach contents: 3 brown, round seeds ca. 8 mm diameter, green fruit pulp ( Lauraceae ). A tissue sample (breast muscle) was saved (now in Uniandes: Andes-T 2662); no voice recordings were made.

Type locality. Colombia: department of Guaviare: municipality of Calamar: beside the caño Negro (1°21’N, 72°54’W; Fig. 1 ), a large creek at an elevation of 470 m, in rolling terrain in the northern sector of the Serranía in Chiribiquete National Park, in dense shrubby matorral dominated by the shrubs Bonnetia sessilis, Senfelderopsis chiribiquetensis and Clusia columnaris of heights between 2 and 3 m: this is the most extensive habitat of the Serranía at middle and upper elevations ( Cárdenas et al 2018).

Diagnosis. Distinguished from T. a. albiventer by the following characteristics: overall size smaller with significantly shorter tarsi, lesser bill height and (males only) wing length ( Table 3, Fig. 2 ); these parameters, and also culmen and tail length, showed little overlap ( Table 1, Figs. 3–4 ); overall darker and more uniform coloration, with less contrast between the gray of the crown and the back, which in albiventer is brighter brown; little or no difference between the color of the back and the shoulders, wing coverts and margins of the outer primaries, which are brighter brown to rufescent in albiventer; the dark streaks of the throat browner, less blackish and averaging less heavy; anterior wing linings darker rufous; underparts averaging darker gray, especially on the chest and flanks. Distinguished from other sympatric Turdus species ( T. arthuri , T. ignobilis debilis ) by the rufous wing linings and bill color (not black, but dark horn color with yellowish tomia); additionally, from the latter by the grayer, less brownish chest, much less extensive white on the abdomen and with the white of the throat not extending beyond the dark streaks onto the upper chest, and by its longer wing and tail.

Description of the holotype. Iris chestnut; bill dark horn color, shading to blackish at base of culmen and dull yellowish on tomia; tarsi and feet dark horn color. Throat white, streaked with dark Brown (near 119B, Dark Drab); chest brownish gray (between 79 and 80, Glaucous), tinged brownish (27, Drab); passing to paler brownish gray (near 27, Drab but grayer) over the lower breast and abdomen; lower medial abdomen and crissum whitish, washed brownish (119D, Drab Gray). Upperparts and tail dark brown, tinged gray (near 119a, Hair Brown); feathers of hindcrown and nape slightly grayer. Outer webs of middle primaries slightly paler (near 27, Drab); wing linings rufous (near 340, Robin Rufous, or slightly darker anteriorly, slightly paler posteriorly); inner webs of secondaries edged pale dull rufous. Total culmen 21.6, commissure width 12.5, bill height 6.0, wing length 115.4, tail length 86.3, tarsus length 30.3 (all measurements in mm), body mass 59.6 g.

Variation among the type series. Seven specimens comprise this series: ICN 39667, adult female, collected in the same net as the type and probably its mate; ICN 33202 and IAVH-A 10770, adult females, both from Puerto Abejas, IAVH-A 11452 and 11562, adult males, from the Cuñare-Amú River on the southeastern edge of the Park; and ICN 24696, adult female, from Araracuara, some 89 km southeast of the Serranía. These specimens present an aggregate distribution between 1°21’N and 0°34’S, and 72°27’and 72°57’W. Most of the seven specimens agree closely with the holotype in coloration; the most divergent is ICN 39667 ( Fig. 3 ), which is decidedly paler on the chest (between Drab 27 and Light Drab 119c), although it agrees in its dorsal coloration and measurements with the rest of the type series ( Table S1).

Etymology. The name for the new taxon commemorates the indigenous Upichía tribe, who were possibly the first to inhabit the Chiribiquete area. This tribe, already reduced by disease during the colonial period, was further decimated and dispersed by the slave-labor practices of the rubber trade of the late 19 th and early 20 th centuries and is presently being absorbed into the more numerous Yukuna peoples. Their language, Matapí, is now all but extinct; some of their lore and worldview was expressed by Matapí-Yukuna (2018), who noted that their name for Chiribiquete, mejeime meme, translates to “echoes of silence”, evocative of its impressive and remote landscape.

Figures

FIGURE 1. Map of Colombia, showing the geographic origin of specimens and tissue samples of Turdus thrushes analyzed in this study. A. Distribution of Turdus leucomelas in Colombia. T. l. upichiarum is restricted to the Serranía de Chiribiquete and Araracuara, whereas T. l. albiventer is found across the Orinoco basin and trans-Andes and T. l. cautor is limited to the humid tip of the Guajira Peninsula. The regions mentioned in this study are listed from north to south as follows: a. the Guajira Peninsula; b. the Santa Marta region; c. Serranía de Perijá; d. Eastern Andes; e. Magdalena River valley; f. Llanos Orientales; g. Serranía de la Macarena; h. Serranía de Chiribiquete (the star denotes the type locality of T. upichiarum); i. forested Amazonian lowlands. B. Distribution of four Turdus thrushes in eastern Colombia. Localities specifically mentioned are numbered north to south as follows; 1. Inírida; 2. Guayabero River; 3. Chiribiquete; d. Puerto Abejas and vicinity; g. Araracuara; h. Leticia. Nominate T. ignobilis occurs on the western slope of the Eastern Andes and usually at somewhat higher elevations than T. i. debilis, but we note several sites where possible intergrades between them exist. T. arthuri occurs rather widely in eastern Colombia, and is sympatric with T. i. debilis at Araracuara and Inírida, and with T. l. upichiarum in Chiribiquete and Araracuara.

FIGURE 2. Bayesian tree based on ND2 sequences showing phylogenetic relationships between T. l. upichiarum and other T. leucomelas from South America. Bayesian posterior probabilities (PP) and maximum likelihood bootstrap values are indicated above and below nodes, respectively, with asterisks indicating maximum values (PP=1.0; bootstrap support= 100). Numbers in front of taxon names refer to sample data in Table 1. The median-joining haplotype network depicts shallow genetic divergence and haplotypes (circles) shared among T. leucomelas from several regions (colors). The size of each circle denotes the number of samples per haplotype. Vertical bars represent the number of substitutions among haplotypes. Note that three T. l. upichiarum share the same haplotype with samples from the Llanos Orientales and Guyana.

FIGURE 3. Plumage variation among populations of T. leucomelas from eastern Colombia. From left to right: T. l. albiventer, male ICN 38400, Meta, Villavicencio, vereda La Llanerita, finca Villa Oria; male ICN 30851, Cundinamarca, Medina, San Francisco de Gazaduje, finca Serranía los Alpes; T. l. upichiarum, male ICN 39668 (Holotype) and female ICN 39667, Guaviare, Calamar, PNN Serranía de Chiribiquete, caño Negro; T. l. upichiarum, female ICN 24696 (Paratype), Amazonas, Araracuara, río Caquetá. Note the overall darker coloration of T. l. upichiarum compared with the contrasting gray and brown upperparts and brighter brown to rufescent wing coverts and primaries in T. l. albiventer.

FIGURE 4. Morphological comparisons among four Turdus thrushes found in eastern Colombia. Note the smaller size overall of T. l. upichiarum with respect to cisandean T. l. albiventer. Turdus i. debilis and T. arthuri show similar morphology, except for the longer tail and tarsi of the latter. Medial line denotes the median, and 2 nd and 3 rd quartiles delimit the box.