The Auk 121(4):1031–1039, 2004 A NEW SPECIES OF ANTSHRIKE (AVES: THAMNOPHILIDAE) FROM THE SERRA DO DIVISOR, ACRE, Bwjy M. Wmnyj,1,3 Df{ni C. Owj,2,4 fi Rtgg T. Bwrknji1 1Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, Louisiana 70803, USA; 2Departamento de Zoologia, Museu Paraense Emílio Goeldi, Caixa Postal 399, 66.017-970, Belém, Pará, Brazil

Agxywfhy.—We describe a new species of Thamnophilus antshrike—T. divisorius ()—from the Serra do Divisor of Acre, Brazil. The new species is known from a single small ridge (though we expect that it is present on other, unexplored ridges in the Acre Arch uplands), and is common in the interior of shrubby woodlands on poor soil physiognomically similar to white-sand habitats in and Amazonia. Thamnophilus divisorius is sister to T. insignis (Streak-backed Antshrike), a narrow endemic of pantepui, and forms a well- supported clade with that species and T. amazonicus (). Thamnophilus divisorius occurs in a remote region within a national park in Brazil; despite its limited range, we are optimistic about its future survival. Received 16 May 2003, accepted 24 June 2004.

Rjxrt.— Descrevemos uma nova espécie de tamnofi lídeo (Thamnophilus divisorius, Choca- do-Acre) oriunda da serra do Divisor, Acre, Brasil. A nova espécie é conhecida de apenas um único cume de serra (embora é esperada existir em outras áreas similares ainda não pesquisa- das nos arredores), e é comúm no interior de bosques de vegetação baixa crescendo em solos pobres que lembram habitats de campina de areia branca e vegetações afi ns nos Guianas e na Amazônia. É fi logeneticamente mais próximo de Thamnophilus insignis (Choca-de-), espécie de distribuição restrita à região de pantepui, e forma um clade com Thamnophilus amazonicus (Choca-canela). Thamnophilus divisorius ocorre numa região remota dentro de um parque nacional e, apesar de ter uma distribuição extremamente restrita, estamos otimistas sobre a sua sobrevivência no futuro.

I J 1996, the fi eld phase of a manage- inventory; B.M.W., D.C.O., and the technician ment plan for the Parque Nacional da Serra D. C. Pimentel Neto conducted the fi eld work. do Divisor (PNSD) in Acre, Brazil, was initi- Although the fi rst phase encompassed only 18 ated. The project was funded by The Nature fi eld days, with observations divided among Conservancy International of Alexandria, six sites in the northern sector of the park, we Virginia, and coordinated in Brazil by the documented several species of previously national offi ce of The Nature Conservancy in unknown or poorly known in Brazil, including Brasília, D.F., the nongovernmental organiza- a striking Thamnophilus antshrike new to sci- tion S.O.S. Amazônia in Rio Branco, Acre, and ence, which we propose to name: the national and regional offi ces of the Instituto Brasileiro do Meio Ambiente e dos Recursos Thamnophilus divisorius sp. nov. Naturais Renováveis (IBAMA). One key aspect Acre Antshrike of the project was a rapid ecological evaluation Choca-do-Acre (Portuguese) (REA; Sobrevila and Bath 1992) of the park’s fl ora and fauna. The ornithology section of Holotype.—MPEG no. 52754; adult male, the Museu Paraense Emílio Goeldi (MPEG) in from Morro Queimado, in the Serra da Belém, Pará, was responsible for the avifaunal Jaquirana (one of the easternmost ridges in the Serra do Divisor), above the leV bank of the rio Moa in Parque Nacional da Serra do 3E-mail: [email protected] 4 Divisor, Municipality of Mâncio Lima, Acre, Present address: Conservation Priorities Coor- ∼ dinator, The Nature Conservancy, Eastern South Brazil (07°26’36”S, 73°40’28”W); 500 m; col- America Division, SHIN Centro de Atividades 05 lected 10 July 1996 by B.M.W., prepared by D. Conjunto J Bloco B, 3o Andar, 71.503-505 Brasília, D.F., C. Pimentel Neto. Tape-recorded by B.M.W., Brazil. Macaulay Library of Natural Sounds (MLNS),

1031 1032 Wmnyj, Owj, fi Bwrknji [Auk, Vol. 121

Cornell Laboratory of Ornithology, Ithaca, oV en the penultimate note, is louder, longer, and New York, no. 79060; Arquivo Sonoro Elias P. of slightly higher peak frequency than the rest Coelho (ASEC), Universidade Federal do Rio de of the series, but does not diff er dramatically in Janeiro, Rio de Janeiro, Brazil, no. BMW 054/10; structure or tonality. Recorded calls appear to be and Isler inventory, Alexandria, Virginia, no. less clearly diff erentiated from those of several BMW.125:21. other Thamnophilus species. Diagnosis: Morphology.—Allocation of the new Distribution.—Known only from the type species to the genus Thamnophilus is diffi cult to locality, the new species probably occurs on justify objectively on the basis of morphology, other, physiognomically similar ridges in the because characters of diagnostic value have not Acre (sometimes called Serra do Moa) Arch been identifi ed for the genus and because the uplands in the Serra do Divisor of Acre, perhaps present group of ∼25 species (as currently classi- extending to the continuous Sierra Contamana fi ed) may not be monophyletic. The type species in Ucayali, (Fig. 1). of Thamnophilus is T. doliatus (), Description of holotype.—(See cover plate.) which is barred black-and-white in the male Alphanumeric color designations were deter- plumage, and mostly rufous-brown in the mined from direct comparison with the Munsell female plumage. These factors notwithstanding, (1994) soil color chart. Crown from base of bill the new species is most similar morphologically to nape semi-glossy black with a few sca ered to members of Thamnophilus. Adult males are albino feathers in forehead and occipital–nuchal readily distinguished from other Thamnophilus regions; not crested. Sides of head and neck species by a combination of the following a fl a er black, less intense and lacking gloss. characters: entirely dark-bluish-gray plumage Feathers of back and scapulars same black as with somewhat blacker hood, wings, and tail, sides of head, widely margined with subtly paler and mo led grayish (rather than mostly white) bluish black (nearest Gley 2, 2.5/1/5PB), impart- underwing coverts. Adult females diff er distinc- ing a weakly mo led eff ect, which is seen to tively from other Thamnophilus species in hav- vary with viewing angle. Rump and uppertail ing almost uniformly bluish-gray facial region coverts dark bluish gray (Gley 2, 3/1/5PB). No and upperparts with slightly darker wings and white interscapular patch; those feathers instead tail, and entirely brownish-orange underparts. dull grayish. Throat subtly grayer than sides of Both sexes may show minute pale spots (white head but darker than remainder of underparts, in male, buff -orange in female) at tips of some which—together with black head and neck upperwing coverts; both sexes have small but region—contributes to a weakly hooded eff ect. more conspicuous spots at the tips of the outer Underparts from breast to undertail coverts, two rectrices; those are reduced to fringes or are including elongated, loosely integrated fl ank absent on the next one or two rectrices. feathers, uniform dark bluish gray, concolor Diagnosis: Voice.—The loudsong (following with rump. Upperwing coverts and tertials Willis 1967) of T. divisorius is similar in pa ern, same semiglossy black as crown. Tiny feathers at structure, and auditory quality to that of T. base of outer primary whitish; feathers at bend doliatus (especially the nominate form), which of wing mixed gray and whitish. Underwing aligns T. divisorius more objectively with the coverts with gray centers and whitish tips, genus Thamnophilus than does its morphology. or a single, whitish, internal band encircling That alignment is supported anecdotally: on the gray center, producing a mo led appearance. morning of its discovery, T. divisorius was heard Primaries blackish, subtly paler on outer edges and tape-recorded by B.M.W. for nearly an hour (visible on folded wing), all except outermost before being seen, and it was clear from its song with contrasting wide silvery-white margins that it was an unnamed Thamnophilus antshrike. 1–2 mm on inner webs, especially visible on ven- Thamnophilus divisorius‘ loudsong diff ers from tral surface, those margins becoming progres- the song of all other Thamnophilus species by the sively more extensive from outermost primary following combination of characteristics: (1) it (which is shorter and wholly blackish) to inner- accelerates in pace (progressively shorter inter- most. Tail graduated, same semiglossy black as note intervals) for approximately half its dura- crown and upperwing coverts. Outermost rectrix tion, slowing slightly and gradually through the with white tip 1.5 mm wide, extending to both fi nal two or three notes; (2) its terminal note, and webs; tips present but decreasing in size on next October 2004] New Antshrike from Acre, Brazil 1033

Fnl. 1. Composite LANDSAT image of the northern half of Parque Nacional da Serra do Divisor (white out- line), Acre, Brazil. The single confirmed locality of Thamnophilus divisorius, “Morro Quiemado,” is indicated by an × ; it is slightly north of the Rio Moa in the Serra da Jaquirana. The view from the ridge, looking northwest, is shown in Figure 2. The ridge system comprising the Acre Arch uplands appears as a textured band running northwest into Ucayali, Peru; a somewhat disjunct system south of the Moa appears to be lower in relief. These areas are virtually unexplored biologically. We expect that T. divisorius will eventually be found on most, per- haps all, of the higher ridges in the region. three pairs of rectrices; two central pairs with Description of allotype.—(See cover plate.) worn tips but apparently lacking any white. SoV MPEG no. 52751. Crown feathers from base of parts in life: iris clear chestnut brown; maxilla bill to occipital region blackish with dark blu- black; mandible black; legs and feet dull bluish ish gray (Gley 2, 3/1/5PB) margins, imparting a gray; soles yellow. weakly mo led eff ect. Sides of head and malar Measurements of holotype.—Bill width at ante- region same dark bluish gray (auricular feath- rior edge of nares 4.9 mm; bill depth at anterior ers with orangish shaV s), tinged with brown- edge of nares 5.7 mm; culmen from anterior edge ish on sides of neck. Remainder of upperparts of nares 13.0 mm; culmen from base (at skull) uniform dark bluish gray, with individual 20.8 mm; wing chords 75.6 (leV ) and 76.2 (right) feathers darkest toward center. Feathers of mm; tail 65.2 mm; tarsus 21.6 mm; mass 23.0 g. chin and throat deep ochraceous with cream- Skull 100% ossifi ed; leV testis 7.9 × 4.8 mm. white center and gray base, such that throat 1034 Wmnyj, Owj, fi Bwrknji [Auk, Vol. 121 appears mo led; face versus throat contrast is Biochemical specimens.—MPEG voucher speci- strong. Remainder of underparts deep ochra- men numbers, followed by biochemical sample ceous or brownish orange (7.5YR 5/8), washed numbers, are 52749 (PNSD 223), 52750 (PNSD subtly darker at sides of breast (7.5YR 4/6) and 224), 52751 (PNSD 225; allotype), 52752 (PNSD brightest in midbelly. Underlying fl ank feathers 226), 52753 (PNSD 227), and 52754 (PNSD 228; extensively bluish gray with brownish-orange holotype). Samples of liver and heart tissue tips. Upperwings same blackish as crown; are preserved in plastic tubes containing 20% most lesser, median, and greater wing coverts DMSO and EDTA buff er solution, and are cur- weakly tinged brownish orange on outer webs rently stored at MPEG. Among many tissue near tips, not suffi ciently strongly to form wing- samples analyzed in construction of a phy- bars or a clear pa ern of margination. Primary logeny of the genus Thamnophilus, especially coverts blackish. Outer webs of inner primaries, pertinent to this description were those of T. secondaries, and tertials also faintly tinged amazonicus (Amazonian Antshrike; LSUMZ brownish orange. Tiny feathers at bend of wing, No. B13045) and T. insignis (Streak-backed and underwing coverts, same brownish-orange Antshrike; LSUMZ No. 7486). as breast and belly. Primaries blackish, marked Etymology.—The name divisorius is an latinized with same pa ern of pale margination on outer adjectival form of the Portuguese word divisor webs as in holotype, but color somewhat more (i.e. boundary) and is given in recognition of the buff (near 7.5YR 8/4). Tail as in holotype but pale great importance of the Parque Nacional da Serra tips limited to outer rectrix, reduced in size, and do Divisor, where the new antshrike was discov- buff -orange instead of white. SoV parts in life: ered. The English name, Acre Antshrike, and the iris clear chestnut brown; maxilla dark gray; Portuguese Choca-do-Acre, call a ention to the mandible dark gray with pale-horn base (vis- Brazilian state of Acre where the park is located ible only from below); legs and feet dull bluish and where the state government plays a critical gray, soles yellow. role in environmental protection of a large area Measurements of allotype.—Bill width at anterior of western Amazonian Brazil. edge nares 4.7 mm; bill depth at anterior edge nares 5.6 mm; culmen from anterior edge nares Rjrfwpx 11.5 mm; culmen from base (at skull) 20.6 mm; wing chords 71.6 (leV ) and 70.9 (right) mm; tail Variation in the type series.—The type series 63.8 mm; tarsus 21.0 mm; mass 22.7 g. Skull 100% comprises the eight specimens listed above. ossifi ed; ovarian mass 4.2 × 2.1 mm; size of largest Three adult males vary slightly from the holo- ovum not recorded, oviduct smooth. type in having minute white spots or tiny Specimens examined: Skins.—Thamnophilus divi- whitish fringes on the outer webs at the tips of sorius: Brazil, Acre (four males, three females, one some (especially innermost) greater upperwing sex unknown; MPEG nos. 52748–52755). In addi- coverts. These whitish markings are discernible tion, plumages of specimens of all other species only on close examination. Specimen MPEG no. of Thamnophilus were compared visually at the 52755 also has a tiny whitish fringe on the outer MPEG, Louisiana State University Museum of web of two scapular feathers, and MPEG no. Natural Science (LSUMZ), and the Academy of 52752 has a single albino crown feather. The lat- Natural Sciences of Philadelphia (ANSP), though ter specimen also shows the most clearly defi ned it was not possible to compare specimens at the blackish hood of all. Among females, MPEG la er directly with those of the new species. nos. 52749 and 52750 show slightly less black- Specimens examined: Tape recordings.— ish in the crown than the allotype (described Thamnophilus divisorius: Brazil, Acre (7, repre- above). The most notable variation in the series senting at least 13 individuals and 4 vocalization of four female-plumaged specimens (including types). All specimens were tape-recorded prior MPEG no. 52748, which is sex unknown, and to collection. Recordings of all other species and represented by only the head and part of the most subspecies of Thamnophilus were com- upper breast, and most of one wing) is seen in pared superfi cially. Recordings of T. divisorius the upperwing coverts. Specimen MPEG no. have been or will be deposited at MLNS, ASEC, 52748 has pale brownish-orange fringes on the MPEG, and the research inventory of lesser, median, and greater coverts; no. 52749 Phyllis and Morton Isler. has rather distinct orange-buff spots on the October 2004] New Antshrike from Acre, Brazil 1035 outer webs of the median and greater coverts. downslope. On the ridgeline, trees grow in high The allotype and MPEG no. 52750 are closely density; however, most are <20 cm diameter at similar, though the la er has slightly more dis- breast height (dbh) and <15 m tall, with nar- tinct pale margins on the tertials. All specimens row canopies. Most taller trees are in the fam- were judged to have 75–100% ossifi ed skulls ily Fabaceae. Understory is dominated by two except female no. 52750, which was unossifi ed. species of plants: (1) extensive, homogeneous That specimen, a juvenile, also had the smallest stands of an unidentifi ed, smooth-leaved, 0.5– ovary mass (2.3 × 1.1 mm) of the three known 1 m tall, light-green terrestrial bromeliad; and females. That its plumage so closely matches (2) sca ered thickets of Gleichenia sp. ferns inter- that of the allotype, which is apparently an twined with thin vines and tree trunks (Fig. 2B). adult female, indicates that the juvenal plumage Plants form impenetrable thickets where the of the female (at least) is almost indistinguish- broken canopy permits sunlight to reach the able from that of the adult female. Males have understory for much of the day. Several spe- a well-developed hook with a slightly basad cies of melastomes were also among the most notch at the tip of the maxilla, which seems to be common understory plants. A lightning strike more formidable (for the 's size) than those that occurred in 1995 (information from local of most other Thamnophilus antshrikes. Female residents) burned ∼0.25 ha of at the crest maxillas appear to be less strongly hooked, but of the ridge and was hot enough to completely there are no signifi cant morphometric diff er- kill all vegetation. Vegetation on the poor soil ences between the sexes. Some standard mea- had barely begun to grow back several months surements are presented in Table 1. later (July 1996). Habitat.—The region of serras that straddles This fl oristically simple, low-stature ridge the Brazil–Peru frontier (the Serra do Divisor forest is physiognomically similar to “stunted in Brazil) is known geologically as the Acre woodland” habitats found on the upper slopes (or Serra do Moa) Arch and is postulated to of summits across pantepui and in the white- be Mio-Pliocene in age (Jordan 1983, Mégard sand “Amazon caatinga” habitats described in 1984). Thamnophilus divisorius is known from Anderson (1981). It is likewise similar to the a single ridge in the more restricted Serra da varillal woodland described by Whitney and Jaquirana, the easternmost of a series of nar- Alvarez (1998) and Alvarez and Whitney (2003), row, roughly north–south ridges in the Serra do who also highlighted the patchy distribution of Divisor, which rises abruptly above a vast, level those habitats in Amazonia and their contribu- plain cloaked in tall forest (Fig. 2A). Soil here tion to terra fi rme habitat mosaicism and overall is extraordinarily thin, sandy, and well-drained species diversity of birds. Interestingly, T. diviso- owing to highly vertical relief and millenia of rius was not found by B.M.W. during three days rainwater surface denudation. What li le soil in April 1997 in a much more extensive, generally remains is buried beneath a deep humus of leaf taller, and biologically more diverse “Amazon li er and springy root masses. Consequently, caatinga” woodland ∼100 km east-southeast of plant diversity is limited and trees are con- the type locality (or ∼50 km west-northwest of spicuously shorter in comparison with the the town of Cruzeiro do Sul). Some areas of that surrounding forest, which is only slightly caatinga woodland were structurally similar to

Tfgj 1. Some standard measurements of Thamnophilus divisorius.

Culmena Wing chordb Tail Tarsus Body mass (mm) (mm) (mm) (mm) (g) Male 20.6 72.8 63.2 21.0 22.3c (range: 20.1–21.5) (range: 70.8–76.2) (range: 61.3–65.2) (range: 20.5–21.6) (range: 21.0–23.0) (n = 4) (n = 4) (n = 2) (n = 4) (n = 3) Female 20.0 70.8 63.2 20.8 22.1 (range: 19.6–20.6) (range: 70.3–71.6) (range: 61.6–64.3) (range: 20.6–21.0) (range: 21.0–22.7) (n = 3) (n = 3) (n = 3) (n = 2) (n = 3) aFrom base at skull. bBoth wings measured, with longest measurement included here. cLightest male (21.0 g) missing tail. 1036 Wmnyj, Owj, fi Bwrknji [Auk, Vol. 121

Behavior and ecology.—Thamnophilus divisorius is a common bird but is generally secretive and diffi cult to detect except by its vocalizations. Pairs foraged apart from mixed-species fl ocks (few of those were encountered on the ridge), keeping mostly within ∼3 m (oV en within 1 m) of the ground within forest. Some individuals rose to as high as ∼8 m aV er tape-recording playback. Birds advanced with short hops, stopping briefl y on both horizontal (usually) or vertical perches, and frequently “hitched” (fol- lowing Whitney and Pacheco 1994) upward on thin trunks and vines before hopping or fl ying a short distance to a new perch. Most forag- ing a ack maneuvers were reaches and gleans to woody and herbaceous substrates within a few centimeters of the head, but males were twice seen to perform upward sally-strikes or sally-pounces of ∼1 m in range to the under- sides of leaves (terminology follows Remsen and Robinson 1990). Those strikes involved violent contact of the foreparts of the bird with foliage. Small arthropods were captured several times, including at least one caterpil- lar and a green orthopteran ∼3 cm in length, Fnl. 2. Parque Nacional da Serra do Divisor, Acre, which was beaten vigorously against a limb Brazil. (A) View from the easternmost ridge in the before being swallowed whole. Thus, foraging Serra da Jaquirana at “Morro Queimado,” type local- behavior was much like that of many other spe- ity of Thamnophilus divisorius (marked × in Fig. 1), cies of Thamnophilus (Whitney et al. pers. obs.). looking northwest over the system of ridges forming Thamnophilus divisorius did not display any dis- the Acre Arch. The ridges are narrowly capped with a tinctive wing or tail motions. homogeneous shrubby woodland growing on deeply Vocalizations.—The loudsong (n = 6 adult weathered soil physiognomically very different from forest only slightly downslope. The long, high ridge males, 3 adult females, and 1–2 of unknown on the horizon, which is probably the one visible in sex and age recorded) of T. divisorius is an Fig. 1 at ∼07°22’S, 73°48’W, would be especially in- unevenly paced series of approximately 15–25 teresting to explore. (B) Microhabitat of T. divisorius (usually ∼20) structurally similar notes that at the type locality. Thin-trunked trees with narrow accelerates gradually, then slows slightly canopies partially shade a nearly impenetrable through the fi nal two or three notes, the whole growth of an unidentified bromeliad and Gleichenia song lasting about 2 s (Fig. 3A). As the series ferns. Photograph was taken in a relatively open accelerates, it also drops slightly in frequency place. (Photos by B.M.W., July 1996.) (<0.3 kHz), then rises just slightly more than that through the fi nal fi ve or so notes to fi nish the ridge forest (though the ground was level at ∼2.0 kHz. The fi rst note is separated from and poorly drained, with none of the unidenti- the second by an interval of 0.1–0.2 s, which fi ed terrestrial bromeliad present); almost all of is longer than that between any other pairs of the avian species encountered on the ridge were notes. The terminal note, and oV en the penul- also found in the caatinga woodland. Although timate, are structured like other notes of the only one small area of the woodland was briefl y series, but are both louder and slightly longer, surveyed, T. divisorius is such a conspicuous spe- as well as peaking at the highest frequency of cies by voice that we suspect that its apparent all. Female loudsongs (specimens collected to absence may be real. Multiple tape-recording document sex) are slightly lower in frequency playbacks of loudsongs from the type locality (0.2–0.3 kHz) than those of males, as judged failed to elicit a response. by the peak frequency of the terminal note. October 2004] New Antshrike from Acre, Brazil 1037

Fnl. 3. Sound spectrograms of the three principal vocalizations recorded for Thamnophilus divisorius. (A) Typical male loudsong showing high-intensity terminal note. (B) Unmodulated two-note call, which is also given singly. (C) Unmodulated caw call with pronounced harmonics.

Three types of calls were recorded. One is a The fi nal call type recorded for T. divisorius is short, unmodulated (following Isler et al. 1998), a quiet cha er, which was given by a juvenile slightly descending note with weak harmonics (MPEG no. 52750) as it accompanied an adult that is sometimes delivered in pairs, the two male and female. The sound is almost certainly notes being separated by ∼0.25 s (n = 2 record- a food-solicitation call. ings; Fig. 3B). It was given repeatedly on one Phylogenetic relationships and origin.—DNA occasion by an adult male aV er collection of sequences from the mitochondrial cytochrome- either its mate or an off spring (sex and age not b (951 base pairs [bp]), ND2 (1,013 bp), and ND3 determined for that specimen). The most com- (332 bp) genes, and from the nuclear introns 5 monly heard call (n = 3 recordings) was a short, (528 bp) and 7 (939 bp) of the beta fi brinogen throaty growl believed to be homologous to the gene, were collected from the holotype (PNSD caw call described for the T. punctatus complex 228) and analyzed phylogenetically with by Isler et al. (1997). The caw of T. divisorius is sequences from other currently recognized spe- an unmodulated, nearly symmetrically hill- cies of Thamnophilus. Missing were some of the shaped note with pronounced harmonics (Fig. recently elevated forms of T. punctatus (Isler et 3C). It is given by both sexes and appears to al. 1997). Detailed methodologies on molecu- function primarily to communicate heightened lar data collection and analysis are available awareness, such as when a potential threat from R.T.B. or can be found in a forthcoming is detected (e.g. a nearby observer). It is not publication on the molecular systematics of normally delivered during routine foraging. Thamnophilus antshrikes. 1038 Wmnyj, Owj, fi Bwrknji [Auk, Vol. 121

A Bayesian analysis (Huelsenbeck and of forest habitats, it may help elucidate the spe- Ronquist 2001) of the combined data using a ciation of many birds and mammals in particu- GTR+G+I model resulted in 100% support for lar, and the evolutionary history of Amazonian a sister relationship between T. divisorius and habitats in general. And because of its location T. insignis, a restricted-range species found in this region of Amazonia, PNSD contains for- in the tepuis of southern , , ests and rivers that are important for migrating and northern border regions of Brazil (Zimmer and overwintering birds from both the northern and Isler 2003). Those two species form a well- hemisphere (including Central America and supported clade with T. amazonicus, which northern South America), and from breeding occurs in lowland forest habitats, almost exclu- areas well to the south in , Paraguay, sively in blackwater and clearwater drainages, and Argentina. Unfortunately, however, through most of the and Guianan PNSD includes only the leV bank of the Rio shield (B. M. Whitney pers. obs.). The relation- Juruá. Because the river could prove to be an ship was also found in the most likely tree (–ln important barrier to genetic exchange between L = 6357.9) from a heuristic search of the com- populations of birds and mammals (as are many bined data using a GTR+G+I model (Swoff ord other long rivers in the Amazon basin), the park 2003). Although the tissue samples of T. amazo- should be expanded to encompass all represen- nicus (from eastern Santa Cruz, Bolivia) and T. tative habitats on the right bank of the river. For insignis (from Cerro de la Neblina, Amazonas, example, populations of the saddleback tama- Venezuela) were collected at points distant from rin (Saguinus fuscicollis) and monk saki monkey type localities of those taxa, voucher skins were (Pithecia monachus), both highly distinctive examined; we are confi dent that they provided primates with sister-taxon replacements across results that allowed accurate placement in the the middle-upper Juruá, are unprotected east phylogeny, even if they should be subject to of the river. spli ing at the species level in the future. Several important challenges must be met if Thamnophilus divisorius, isolated in the Acre PNSD is to maintain its integrity. All have to do Arch ridge system and widely disjunct T. insig- with pervasive and increasing manmade altera- nis, on the slopes of tepuis, have undergone a tions to the forest and rivers. These alterations high degree of diff erentiation. Raw sequence include subsistence practices such as clearing divergence at cytochrome-b between T. diviso- of forest for homesteads and cultivation of food rius and T. insignis was 7.9%; their sister rela- crops, raising of livestock, and hunting, which tionship is thus rather distant. Morphology and have been going on for decades in some areas. vocalizations in T. divisorius, T. insignis, and T. Although subsistence activities have steadily amazonicus are not very helpful in recovering degraded the resources over the years, com- relationships, especially in regard to T. divi- mercial practices have a more immediate and sorius. However, the three species have main- devastating potential. Those practices include tained one common characteristic: all occupy wholesale timber extraction, hunting with structurally and physiognomically similar trained dogs and highly skilled trackers for habitats that have especially nutrient-poor soils. commercial sales in population centers such as The ability of ancestral stocks to colonize these Cruzeiro do Sul, gold mining, capture of parrots fl oristically impoverished habitats (ridge forest and other birds and mammals for the pet trade, in Acre, melastome-dominated woody scrub and smuggling of narcotics and contraband forest on the slopes of tepuis) has, in the case of from Peru. the T. amazonicus clade, led to marked diversifi - Several hundred families live within the cation at the species level. borders of PNSD, mostly along the rios Juruá, Conservation.—The entire known popula- Azul, and Moa. Plans for relocating the resi- tion of T. divisorius is offi cially protected in the dents to areas outside the park boundaries are PNSD. The park encompasses one of the most underway, with orientation from the Brazilian biologically diverse areas on Earth. It covers a National Colonization and Agrarian Reform vast region (605,000 ha) and is located in the Agency (INCRA). The fi rst station for monitor- middle-western sector of upper Amazonia, ing the park is being built and will be manned including much of the Acre Arch uplands. by local residents. These initiatives and the full Because PNSD comprises a remarkable diversity implementation of the park’s management plan, October 2004] New Antshrike from Acre, Brazil 1039 including an ecotourism component, lead us to Biogeography and systematics of be optimistic about conservation prospects for the Thamnophilus punctatus complex. the region’s extraordinary biodiversity. Ornithological Monographs 48:355–381. Ixjw, M. L., P. R. Ixjw, fi B. M. Wmnyj. 1998. Use of vocalizations to establish species limits Ahpt|jilrjyx in (Passeriformes; Thamnophilidae). Auk 115:577–590. Our most sincere thanks to V. Passos, M. Scarcello, Jtwif, T., B. Ixfhpx, R. Arjinljw, J. Bwj|jw, F. Figueiredo, L. Honigmann, and D. C. Pimentel V. Rfrtx, fi C. Ait. 1983. Andean tecton- Neto for help in working in Parque Nacional da ics related to geometry of subducted Nazca Serra do Divisor. We thank IBAMA-Brasília for spe- plate. Geological Society of America Bulletin cial collecting permits issued to D.C.O., whose work 94:341–361. was supported in part by a fellowship from CNPq. M”lfwi, F. 1984. The Andean orogenic period We are grateful to P. Schneider, E. Gonçalves, and and its major structures in central and north- M. Silvanira Ribeiro Barbosa of the Laboratório de ern Peru. Journal of the Geological Society of Polimorfi smo de DNA, Departamento de Genética London 141:893–900. at the Universidade Federal do Pará, Belém, Brazil Mxj. 1994. Soil Color Charts, revised ed. for collecting the DNA sequences of T. divisorius; and Macbeth Division of Kollmorgan Instruments to A. Aleixo for his valuable assistance in seeing this Corporation, New Windsor, New York. work through to completion. Molecular analysis was Rjrxj, J. V., fi S. K. Rtgnxt. 1990. A classi- supported in part by National Science Foundation fi cation scheme for foraging behavior of birds (NSF) grants DBI-9974235 and DEB-0332093 to R.T.B. in terrestrial habitats. Studies in Avian Biology The editors of The Auk were most patient as we col- 13:144–160. laborated with Brazilian colleagues over a period of Stgwj{nf, C., fi P. Bfym. 1992. Evaluacion several months. Frozen tissues of Thamnophilus insig- ecologica rápida: Um manual para usuarios nis (prepared by J. P. O'Neill) and T. amazonicus (pre- de América Latina y el Caribe. The Nature pared by D. C. Schmi ) were provided by the Genetic Conservancy, Arlington, Virginia. Resources Collection of the Louisiana State University S|tkktwi, D. L. 2003. PAUP*. Phylogenetic Museum of Natural Science. We thank F. de Lima of Analysis Using Parsimony (*and Other the MPEG for help in working with the specimens of Methods), version 4.0b10. Sinauer Associates, the new antshrike, and T. Schulenberg for examining Sunderland, Massachuse s. the voucher specimen of T. insignis from Cerro de la Wmnyj, B. M., fi J. A. A{fwj. 1998. A new Neblina for us. M. H. Matsumoto of the GIS depart- Herpsilochmus antwren (Aves: Thamnophilidae) ment of The Nature Conservancy in Brazil kindly from northern Amazonian Peru and adjacent prepared the satellite image (Fig. 1). The manuscript : The role of edaphic heterogeneity of benefi  ed from the thoughtful comments of M. and terra fi rme forest. Auk 115:559–576. P. Isler, P. Stouff er, and two anonymous reviewers. Wmnyj, B. M., fi J. F. Pfhmjht. 1994. Behavior Finally, we are greatly indebted to L. McQueen for his and vocalizations of Gyalophylax and magnifi cent illustration of the new species. Megaxenops (Furnariidae), two li le-known genera endemic to northeastern Brazil. Condor Lnyjwfywj Cnyji 96:559–565. Wnnx, E. O. 1967. The Behavior of Bicolored A{fwj, J. A., fi B. M. Wmnyj. 2003. Eight Antbirds. University of California Publications new bird species for Peru and other distribu- in Zoology, no. 79. tional records from white-sand of the Znrrjw, K. J., fi M. L. Ixjw. 2003. Family northern Peruvian Amazon, with implications Thamnophilidae (typical antbirds). Pages 448– for biogeography of northern South America. 681 in Handbook of the Birds of the World, vol. Condor 105:552–566. 8 (J. del Hoyo, A. Ellio , and D. A. Christie, Hjxjgjhp, J. P., fi F. Rtvnxy. 2001. Eds.). Lynx Edicions, Barcelona, Spain. MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics 17:754–755. Ixjw, M., P. Ixjw, fi B. Wmnyj. 1997. Associate Editor: P. C. Stouff er