Xiphorhynchus polystictus ( Salvin & Godman, 1883 )

Raposo, Marcos A., Kirwan, Guy M., Fonseca, Odirlei, Selvatti, Alexandre Pedro, Höfling, Elizabeth & Stopiglia, Renata, 2025, Towards a more coherent taxonomy for the woodcreepers Xiphorhynchus guttatus and X. guttatoides (Aves: Passeriformes: Dendrocolaptidae), Zootaxa 5683 (4), pp. 492-512 : 506

Xiphorhynchus polystictus ( Salvin & Godman, 1883)

Dendrornis polysticta Salvin & Godman, 1883: 210

Dendrornis rostripallens sororia Berlepsch & Hartert, 1902: 63

Xiphorhynchus guttatus connectens Todd, 1948: 8

Type series: The syntypes of Dendrornis polysticta Salvin & Godman, 1883 , are three adult females at the Natural History Museum, Tring: NHMUK 1889.5 .14.644, collected on 15 October 1879 ; NHMUK 1889.5 .20.516, collected on 31 May 1880 ; NHMUK 1889.5 .14.645, collected on 31 May 1880 , all by Henry Whitely , at Bartica Grove, Guyana ( Warren & Harrison 1971; M.A. R. and R.S. pers. obs.) .

Diagnosis: Closely resembles X. guttatoides , but has more strongly marked streaking both above and below, and for the most part a black bill versus the silvery-gray bill of X. guttatoides . It is distinguished from X. guttatus by having less chestnut plumage, different measurements, and a totally different vocalization. Fonseca et al. (in prep.) found that the number of notes in the song, the total duration of the song, and the interval between notes readily distinguish X. polystictus from X. guttatus (see above in the “Diagnosis” of X. guttatus ). Xiphorhynchus polystictus also differs from X. eytoni and X. vicinalis by lacking the whitish throat and whitish underparts streaking, both of which are more suffused olive-brown in this species.

Variation: Todd (1948) claimed that X. polystictus intergrades with X. guttatoides in the region of the Rio Negro, from where he described X. g. connectens , named in recognition of the fact that his new taxon formed a link between those taxa, and on the basis that the underparts are more buff, and the pale upperparts streaking is heavier and deeper buff. However, the molecular phylogeny of Rocha et al. (2015) clearly established the basis for considering X. polystictus and X. guttatoides as separate lineages; based on our analysis the name X. connectens applies to hybrids between these two taxa.

Morphometrics: Males of X. polystictus have mean values larger than females in culmen, wing and tail lengths. Wing length in X. polystictus is significantly shorter than that of all other species, culmen length is also significantly shorter than other species except X. guttatus , and tail length is significantly shorter than in X. eytoni and X. vicinalis (see Tables 2 and 3).

Range: Southern Venezuela (in the valleys of the Ríos Caura and Orinoco as far as Munduapo), Guyana, Suriname, French Guiana, and northern Brazil, west of the Negro and north of the Amazon in the Guiana and Imeri areas of endemism (see Figs. 3‒4 ).

Figures

FIGURE 3. Map depicting the distribution of plumage analyses: black circles, morphotype 1, green area, Atlantic Forest area of endemism (AE); white triangles, morphotype 2, purple area, Guiana AE; black diamonds, morphotype 3, red and grey areas, Napo-Inambari AE and Cerrado Biome, respectively; and grey squares, morphotype 4, yellow and blue AEs, Xingu-Belém and Rondônia-Tapajós, respectively, and grey and light green areas, Cerrado and Caatinga Biomes, respectively.

FIGURE 4. Map depicting results of taxognosis analyses and the taxonomic proposal: black circles, Xiphorhynchus guttatus; white triangles, X. polystictus; black diamonds, X. guttatoides; white stars, X. vicinalis; and grey squares, X. eytoni.