Hylophylax

Isler, Morton L., Bravo, Gustavo A. & Brumfield, Robb T., 2013, Taxonomic revision of Myrmeciza (Aves: Passeriformes: Thamnophilidae) into 12 genera based on phylogenetic, morphological, behavioral, and ecological data, Zootaxa 3717 (4), pp. 469-497 : 484-485

Hylophylax clade

Phylogenetic relationships.—The Hylophylax clade ( Figs. 1 and 2 ) consists of two well-supported genera, Hylophylax and Hypocnemoides . The following comparisons examine distinctions between them and identify synapomorphies for later use in comparisons to other clades in the Pyriglenini. Hylophylax includes H. naevioides (Lafresnaye) , H. naevius (Gmelin) , H. punctulatus (Des Murs) . Hypocnemoides includes H. melanopogon (Sclater) , and H. maculicauda (Pelzeln) .

Biogeography. —Representatives of Hylophylax and Hypocnemoides occur throughout Amazonia. One Hylophylax species is trans-Amazonian.

Plumage.—The two genera are distinctive in plumage. Hypocnemoides species are gray above with white edges to blackish wing coverts; males have a black throat and gray underparts; females underparts are primarily white. Species of Hylophylax are yellowish brown but boldly patterned; most species have black throats or malars, white spots on posterior upperparts, black spots on anterior underparts, and black wing coverts with large spots on tips.

Morphometrics.—The two genera are similar morphometrically except for bill proportions ( Tables 2 and 3)

Loudsongs.—Loudsongs of Hypocnemoides species consist of a long, rapidly delivered series of ascending and descending notes; those of Hylophylax species consist of a series of doublets, varying in duration and frequency pattern by species, but readily identifiable as Hylophylax loudsongs.

Habitat.— Hypocnemoides species are closely associated with streams and other water related habitats. Hylophylax punctulatus primarily inhabits seasonally flooded evergreen forest. The remaining Hylophylax species inhabit the understory of evergreen forest, both terra firme and várzea, and mature second growth.

Foraging behavior.—Species of Hylophylax often fly among vertical perches <2 m from the ground while sallying to substrates, and they accompany mixed flocks or follow army ants regularly. Hypocnemoides species hop through branches and vines mostly <2 m from the surface, often (but not always) over water, sally to substrates including water surfaces, and occasionally join mixed flocks or follow army ants.

Tail and wing movements.— Hylophylax species hold their tails below the plane of the body, flick them upward to just above plane of body, and then lower them slowly. Hypocnemoides species hold their tails up over plane of body, frequently flicking them up even higher while flicking wings constantly.

Nest architecture.— Hylophylax nests are hanging cups slung from between two horizontal branches or a branch fork close to ground (known for 2 spp.; recent addition: Greeney 2007). The nest of Hypocnemoides (known for melanopogon ) is a pouch with its entrance near the top, placed over water and slung from a variety of surfaces.

Discussion.—These well-marked genera have not been associated historically. Their common heritage appears to be reflected only in similarities of morphometrics (other than bill shape) and aspects of foraging behavior.

Taxonomic Recommendations.— Hylophylax and Hypocnemoides should be maintained as distinct genera based on differences in plumage, bill proportions, loudsongs, nests, and tail and wing movements, and supported by habitat differences.

Figures

FIGURE 1. Maximum-likelihood tree of a subset of the Thamnophilinae, showing that Myrmeciza is polyphyletic (species names in these clades are emboldened). Members of Myrmeciza are placed in eight different well-supported clades in the Microrhopiini, Pithyini, and Pyriglenini. The color of the circles at nodes indicates bootstrap support values,> 70 % (black), 50 - 70 % (gray), <50 % (white).

FIGURE 2. Bayesian consensus tree of a subset of the Thamnophilinae, showing that Myrmeciza is polyphyletic (species names in these clades are emboldened). Members of Myrmeciza are placed in eight different well-supported clades in the Microrhopiini, Pithyini, and Pyriglenini. The color of the circles at nodes indicates posterior probability support,> 0.95 (black), 0.95 – 0.75 (gray), <0.75 (white).