Birds of North and Middle America, part V/Genus 9. Myrmotherula Sclater

by Robert Ridgway

 

Genus MYRMOTHERULA Sclater.

Myrmotherula Sclater, Proc. Zool. Soc. Lond., 1858, 234. (Type, Muscicapa pygmsea Gmelin.)

Myrmotherium (emendation) Cabanis and Heine, Mus. Hein., ii, July, 1859, 12, footnote.

Very small Formicariidæ (length less than 100 mm.) with bill slender, nearly as long as head, tail less than two-thirds (sometimes less than half) as long as wing, and plumage either conspicuously streaked or else mostly uniform gray or slate color.

Bill slender, depressed, nearly as long as head, its width at frontal antiæ very much greater than its depth at same point, and equal to about half the distance from nostril to tip of maxilla or less; culmen distinctly but not sharply ridged, straight for about basal half then more and more decurved terminally, the tip of maxilla minutely but distinctly uncinate; maxillary tomium slightly but decidedly concave, minutely but distinctly notched subterminally; mandibular tomium nearly straight, minutely notched subterminally; gonys nearly straight terminally, gently convex basally. Nostril exposed, widely separated from feathering of frontal antiæ (the intervening space occupied by membrane), broadly (longitudinally) oval, the internal tubercle visible within the posterior half. Rictal bristles present but minute. Wing moderate, with longest primaries extending decidedly beyond secondaries; sixth and seventh, fifth, sixth, and seventh, or sixth, seventh, and eighth, primaries longest, the tenth (outermost) more than half to about three-fifths as long as the longest, the ninth shorter than secondaries. Tail decidedly less than half as long as wing (M. pygmæa) to slightly more than half as long, very slightly to decidedly rounded, the rectrices (10 in M. pygmæa and M. cinereiventris?,^[1] 12 in M. surinamensis and M. assimilis) rather narrow, rounded terminally. Tarsus much longer than exposed culmen, much shorter than tail and about one-third as long as wing in M. surinamensis, very much shorter than tail and decidedly less than one-third as long as wing in M. cinereiventris and M. assimilis, nearly as long as tail and much more than one-third as long as wing in M. pygmæa, distinctly scutellate, the plantar scutella in two longitudinal series; middle toe, with claw, much shorter than tarsus; outer toe, without claw, reaching to beyond middle of subterminal phalanx of middle toe, the inner toe decidedly shorter; hallux about as long as inner toe but much stouter; basal phalanx of middle toe wholly united to outer toe, for about half its length to inner toe; claws moderate in size and curvature, that of the hallux much shorter than the digit. Plumage soft and full, that of the rump much developed and fluffy; pileum not crested.

Coloration. — Adult males black above, conspicuously streaked with white, the wing with two broad white bands, or else plain gray or slate color above, with small white tips to wing-coverts, the tail with white terminal spots; the under parts white streaked with black (M. surinamensis) or immaculate pale yellow (M. pygmæa), or plain gray or slate color (M. cinereiventris and M. assimilis); adult females with head and neck tawny or cinnamomeous, streaked with black above, otherwise much like adult males, or else with under parts cinnamomeous.^[2]

Nidification. — Nest made of fine roots and grass and suspended in a fork; eggs white or greenish- white.

Range. — Isthmus of Panamá to Cayemie and Amazon Valley. (At least four species.)^[3]

KEY TO THE SPECIES OF MYRMOTHERULA.

a. Under parts white, streaked with, black. (Panamá to Guiana and western Ecuadór.)

Myrmotherula surinamensis, adult male (p. 62).

aa. Under parts neither white nor streaked with black.

b. Under parts buffy, deepening into tawny on chest.

Myrmotherula surinamensis, adult female (p. 62).

bb. Under parts of body pale straw or primrose yellow.

c. Pileum narrowly streaked with pale yellow or yellowish white; throat white. (Panamá to Cayenne and Peru)

Myrmotherula pygmæa, adult male (p. 64).

cc. Pileum streaked with pale rufous or tawny; throat buff or pale tawny.

Myrmotherula pygmæa, adult female (p. 64).

MYRMOTHERULA SURINAMENSIS (Gmelin).

SITRINAM ANTWREN.

Adult male. — Pileum, hindneck, back, and scapulars black, narrowly streaked with white, the feathers of back extensively white basally; rump plain gray (nearly no. 6), much paler posteriorly; upper tail-coverts dusky, indistinctly margined terminally with whitish; tail black, the rectrices tipped with white and edged on middle portion with the same; wings black, the middle and greater coverts broadly tipped with white (forming two very conspicuous bands across wing), the remiges edged (except on basal portion of distal secondaries and proximal primaries) with white; under parts white, the throat narrowly, the chest, breast, sides, and flanks broadly, streaked with black; under wing-coverts and broad edgings. to inner webs of primaries white; maxilla dull black, mandible dull whitish (in dried skins); legs and feet pale yellowish gray (in dried skins); length (skins), 90-107 (96); wing, 49.5-52.5 (51); tail, 26-28.5 (26.9); culmen, 14-15.5 (15); tarsus, 16.5-18.5 (17.2); middle toe, 9.5-10.5 (9.9).^[4]

Adult female. — Pileum bright tawny, the occiput and posterior part of crown streaked with black, the hindneck more buffy and with black streaks broader; back and scapulars black, streaked with whitish (sometimes intermixed with grayish) , the median interscapulars extensively white basally, forming a conspicuous patch when feathers are parted; rump buffy grayish, the upper tail-coverts darker, indistinctly margined with whitish; tail black, the rectrices tipped with white and edged for middle portion with same; wings black, the middle and greater coverts broadly tipped (mostly on outer webs) with white, the remiges edged (except on basal portion of distal secondaries and proximal primaries) with white; under parts plain buffy white, deepening into buff on chest and tawny-buff on malar region, the sides and flanks tinged with pale buffy grayish and, sometimes, very indistinctly streaked with darker; bill, etc., as in adult male; length (skins), 87-95 (90.5); wing, 48-52 (49.8); tail, 25.5-27 (25.7); tarsus, 14-15.5 (14.8); middle toe, 10.^[5]

Young female. — Similar to the adult female but without any concealed white on interscapular region and under parts more deeply colored (buff deepening into tawny on chest and sides of head and neck).

Panamá (Verágua; Panamá; Lion Hill; San Pablo), through Colombia (Turbo; Remédios, Antioquía; Bogotá), Venezuela (Munduapo; Nicare; La Prición, Rio Caura; Rio Mato; Suapuré), to British Guiana (Demerara; Camacusa; Takutu R.; Carimang R.) and western Ecuadór (Esmeraldas; Chimbo; Gualaquiza; Gualea; Foreste del Rio Peripa; San Nicolas; San Javier; Pambilár; Intac),^[6] Cayenne, and eastern Brazil.

[Sitta] surinamensis Gmelin, Syst. Nat., i, pt. i, 1788, 444 (Surinam; based on Surinam Nuthatch Latham, Gen. Hist., iv, 72, pi. 62).

Myrmotherula surinamensis Sclater, Proc. Zool. Soc. Lond., 1858, 234, pi. 141, fig.l (monogr.); Cat. Am. Birds, 1862, 179 (Cayenne ; Esmeraldas, w. Ecuador); Cat. Birds Brit. Mus., xv, 1890, 231, part. — Cassin, Proc. Ac. Nat. Sci. Phila., 1860, 190 (Turbo, Colombia). — Lawrence, Ann. Lyc. N. Y., vii, 1862, 293 (Lion Hill, Panamá). — Sclater and Salvin, Proc. Zool. Soc. Lond., 1864, 356 (Lion Hill); 1879, 525 (Remédios, Antioquía, Colombia; habits; descr. nest and eggs). — Salvin, Ibis, 1874, 311 (Turbo, Colombia; Panamá); 1885, 425 (Camacusa, British Guiana). — Berlepsch and Taczanowski, Proc. Zool. Soc. Lond., 1883, 564 (Chimbo, w. Ecuadór; crit.). — Salvin and Godman, Biol. Centr.-Am., Aves, ii, 1892, 209, part. — Salvadori and Festa, Boll. Mus. Zool., etc., Torino, xv, no. 362, 1899, 29 (Gualaquiza, e. Ecuadór; Foreste del Rio Peripa, w. Ecuadór). — Bangs, Proc. New Engl. Zool. Club, ii, 1900, 23 (Loma del León, Panamá). — Goodfellow, Ibis, 1902, 64 (San Nicolas and Gualea, w. Ecuadór). — Berlepsch and Hartert, Novit. Zool., ix, 1902, 73 (Munduapo, etc., Venezuela; crit.). — Hartert, Novit. Zool., ix, 1902, 612 (San Javier and Pambilár, n. w. Ecuadór; crit.). — Hellmayr, Bull. Brit. Orn. Club, xvi, 1906, 53 (Para, Brazil). — Berlepsch, Novit. Zool., XV, 1908, 154 (Cayenne).

[Myrmotherula] surinamensis Sclater and Salvin, Nom. Av. Neotr., 1873, 71. — Sharpe, Hand-list, iii, 1901, 20.

Myrmotherula surinamensis surinamensis Menegaux and Hellmayr, Bull. Soc. Philom., ser. 9, viii, 1906, 48 (crit.).

M[yrmotherium] surinamense Cabanis and Heine, Mus. Hein., ii, July, 1859, 13, footnote.

M[yrmotherula] surinamensis typica Sclater, Cat. Birds Brit. Mus., xv, 1890, 232, in list of specimens (Verágua, Panamá, and San Pablo Station, Panamá; Bogotá and Remédios, Colombia; Intac and Esmeraldas, w. Ecuadór; Takutu River, Carimang River, and Camacusa, Brit. Guiana).

Myiothera pusilla Pucheran (ex Cuvier, manuscript), Archiv. Mus. Paris, vii, 1855, 335, part (Cayenne; = adult male; see Menegaux and Hellmayr, Bull. Soc. Philom., 1906, 48).

MYRMOTHERULA PYGMÆA (Gmelin).

PYGMY ANTWREN.

Adult male. — Pileum and hindneck black, narrowly streaked with pale yellowish buff or buffy whitish; scapulars and interscapulars black, the former with outer web broadly edged with yellowish white, the latter with much less distinct whitish edgings; rump pale gray, slightly tinged with buffy yellowish; tail black, the rectrices narrowly edged with grayish; wings black, the middle and greater coverts broadly tipped (on outer webs) with yellowish white (forming two conspicuous wing-bands), the remiges narrowly edged (except on basal portion of distal secondaries and proximal primaries) with yellowish white; auricular and suborbital regions pale yellowish buffy, margined above and below by a rather broad postocular and a malar streak of black; chin and throat white; rest of under parts primrose or pale straw yellow, including under wing-coverts and broad edgings to inner webs of remiges; maxilla blackish brown with paler tomium, mandible dull yellowish or whitish in dried skins, gray in life;^[7] iris dark brown;^[7] legs and feet horn color in dried skins, olive-green in life;^[7] length (skin), 65; wing, 38.5; tail, 16; culmen, 13; tarsus, 15.5; middle toe, 8.5.^[8]

Adult female. — Similar to the adult male "but cap striped with pale rufous; throat fulvous."^[9] Panamá (Lion Kill; Panamá) through Colombia (Rio Truando; Bogotá), Venezuela (La Pricion, Rio Caura), British Guiana (Bartica Grove; Camacusa), Ecuadór (Rio Napo; Sarayacu; Vallc de Zamora) and Peru (Pebas; Yurimáguas; Chamicuros; Upper Ucayali; Xeberos; Chyavetas; Tarapata) to Cayenne and western Brazil (Borba and Humaytha, Rio Madeira).

[Muscicapa] pygmæa Gmelin, Syst. Nat., i, pt. ii, 1789, 933 (Cayenne; based on Petit Gobe-mouche tacheté de Cayenne Daubenton, Pl. Enl., pl. 831, fig. 2).

Musciapa pygmæa Latham, Index Orn., i, 1790, 488. — Vieillot, Nouv. Diet, d'Hist. Nat., xxi, 1818, 484 (Cayenne).

F[ormicivora] pygmæa Cabanis, Wiegmann's Archiv für Naturg., xiii, pt. i, 1847, 227.

[Formicivora] pygmæa Bonaparte, Consp. Av., i, 1850, 200.

Formicivora pygmæa Burmeister, Syst. Ueb. Th. Bras., iii, 1856, 77. — Sclater, Proc. Zool. Soc. Lond., 1855, 147 (Bogotá, Colombia); 1858, 67 (e. Ecuadór).

Myrmotherula pygmæa Sclater, Proc. Zool. Soc. Lond., 1858, 234 (monogr.); Cat. Am. Birds, 1862, 179 (Rio Napo, e. Ecuadór); Cat. Birds Brit. Mus. xv, 1890, 230 (Bartica Grove and Camacusa, Brit. Guiana; Pebas, Yurimaguas, and Chamicuros, e. Peru; Rio Napo and Sarayacu, e. Ecuadór; Bogotá, Colombia). — Cassin, Proc. Ac. Nat. Sci. Phila., 1860, 190 (Rio Truando, Colombia).^[10] — Lawrence, Ann. Lyc. N. Y., vii, 1862, 235 (Lion Hill, Panamá).^[10] — Sclater and Salvin, Proc. Zool. Soc. Lond., 1866, 185 (Upper Ucayali, e. Peru); 1867, 750 (Xeberos, Yurimaguas, and Chyavetas, e. Peru), 978 (Pebas, e. Peru); 1873, 274 (Upper Ucayali, Xeberos, Yurimaguas, Chyavetas, Chamicuros, and Pebas, e. Peru); 1879, 624 (Yuracares, Bolivia). — Pelzeln, Orn. Bras., ii, Abth., 1869, 80; iv, Abth., 1870, 417.— Salvin, Ibis, 1870, 311 (Rio Truando, Colombia); 1874, 311 (synonymy); 1885, 425 (Brit. Guiana). — Taczanowski, Proc. Zool. Soc. Lond., 1882, 30 (Yurimaguas, e. Peru); Orn. du Pérou, ii, 1884, 37. — Berlepsch, Journ. für Orn., 1889, 304 (Tarapata, n. Peru); Novit. Zool., xv, 1908, 154 (Cayenne). — Salvadori and Festa, Boll. Mus. Zool., etc., Torino, xv, no. 362, 1899, 29 (Valle de Zamora, Ecuadór). — Berlepsch and Hartert, Novit. Zool., ix, 1902, 73 (La Pricion, Rio Cuara, Venezuela). — Hellmayr, Novit. Zool., xiv, 1907, 382 (Borba and Humaytha, Rio Madeira, Brazil; crit.). — Snethlege, Bol. Mus. Goeldi, v, 1908, 55 (Bom Lugar, Rio Purús, n. Brazil).

[Myrmotherula] pygmæa Sclater and Salvin, Nom. Av. Neotr., 1873, 71. — Sharpe, Hand-list, iii, 1901, 20.

M[yrmophila] pygmæum Cabanis and Heine, Mus. Hein., ii, July, 1859, 13, footnote.

---

1. According to Dr. Sclater M. pygmæa has only 10 rectrices, and a specimen of M. cinereiventris apparently has only 10.
2. I have not seen females of M. cinereiventris nor of M. assimilis.
3. The following species, referred to Myrmotherula by Dr. Sclater, I have not seen and therefore have no very clear idea of the limits of the group: M. guttata (Vieillot), M. spodionota Sclater and Salvin, M. atrogularis Taczanowski, M. hæmatonota (Sclater), M. pyrrhonota Sclater and Salvin, M. erythrura Sclater, M. erythronota (Hartlaub), M. hauxwelli (Sclater), M. longipennis Pelzeln, M. brevicauda (Swainson), M. urosticta (Sclater), M. inornata Salvin, M. unicolor (Ménétriés), M. longicauda Berlepsch and Stolzmann, M. sororia Berlepsch and Stolzmann, M. guayabambæ Sharpe, M. lafresnayeana (D'Orbigny), M. viduata Hartert, M. sanctæmartæ Allen, M. behni Berlepsch and Leverkuhn, and M. boliviana Berlepsch. It is not unlikely that when all these species can be critically compared a further subdivision of the genus may be required.
4. Four specimens.
5. Five specimens.

   Locality.	Wing.	Tail.	Culmen.	Tarsus.	Middle toe.
   males.
   Three adult males from Panamá (line of railway)	50.5	26.3	15.3	17.3	10
   One adult male from Turbo, n. w. Colombia	52.5	28.5	14	17	9.5
   females.
   Three adult females from Panamá	49	26.2	15.2	17.5	10
   One adult female from British Guiana	50	23	14	17.5	10

6. I have seen specimens from Panamá, Colombia, and British Guiana only.
7. Cherrie; see Berlepsch and Hartert, Novit. Zool., ix, 1902, 73.
8. One specimen from Panamá.
9. Sclater, Cat. Birds. Brit. Mus., xv, 1890, 230. I have not seen the female of this species.
10. These two references, very strangely, are placed under M. surinamensis in the Biologia Centrali- Americana (Aves, ii, 209). I have seen the specimens on which they are based, and they are M. pygmæa, not M. surinamensis.